IGCSE Chemistry Past Papers & Solved Topic Questions | Free Resources

1.1.1 Properties of Solids Liquids and Gases Paper 4 IGCSE Chemistry Topic Questions

Q1: (a) Use ideas about the movement and arrangement of particles to explain why:

Solids have a definite volume and shape
Liquids have a definite volume but no definite shape
Gases have no definite volume or shape

.................................................................................................................................................... [4]

....................................................................................................................................................

Mark scheme: (a) Any four from: [4]

Solids: particles close together / no space between particles / particles arranged regularly / particles touching
Solids: particles only vibrate
Allow: particles cannot move / particles in fixed positions
Liquids: particles can slide over each other / particles have limited movement
Ignore: particles can move unqualified
Liquids: particles close together / particles not arranged regularly / particles arranged randomly / particles not in fixed positions
Ignore: particles further apart than in solids
Gases: particles far apart / particles arranged randomly
Gases: particles can move everywhere / particles move anywhere / particles move randomly
Note: It must be clear which state is being referred to
Note: There must be reference to particles (or atoms / molecules / ions) in the answer to gain marks

Solution

Solids have a definite volume and shape because the particles are close together, arranged regularly, and can only vibrate in fixed positions.

Liquids have a definite volume but no definite shape because the particles are close together, arranged randomly, and can slide over each other with limited movement.

Gases have no definite volume or shape because the particles are far apart, arranged randomly, and can move everywhere or randomly.

1.1.2 Structure of Solids Liquids and Gases Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Question Paper:

(a) Complete the table, using ticks (✔) and crosses (✘), to describe the properties of gases, liquids and solids.

state of matter	particles are touching	particles have random movement	particles are regularly arranged
gas
liquid
solid

Mark Scheme:
1 mark for each correct row.

State touching random movement regularly arranged

Gas ✔

Liquid ✔ ✔

Solid ✔ ✔

State	touching	random movement	regularly arranged
Gas		✔
Liquid	✔	✔
Solid	✔		✔

Solution

(i) Gases diffuse because of the random motion of molecules or particles.

(ii) Gas: Hydrogen
Explanation: Hydrogen has the lowest relative molecular mass, hence it diffuses faster.

Solution

(i) Nitrogen gas diffuses faster than chlorine gas because nitrogen has a smaller relative molecular mass (Mr). Nitrogen molecules move faster than chlorine molecules.

(ii) Nitrogen gas diffuses faster at the higher temperature because the molecules move faster and have more energy.

1.1.3 State Changes Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1:
Substances can change state.
- (i) Boiling and evaporation are two ways in which a liquid changes into a gas.
  Describe two differences between boiling and evaporation.
  1. ..........................................................................................................................................
  2. ....................................................................................................................................[2]..
- (ii) Name the change of state when:
  - A gas becomes a liquid: ................................................................................................
  - A solid becomes a gas: ..........................................................................................[2]......
Mark Scheme:
- (i):
  - Boiling happens at a specific temperature (1)
  - Boiling has bubbles (1)
- (ii):
  - A gas becomes a liquid: condensation (1)
  - A solid becomes a gas: sublimation (1)

Solution

(i) Boiling and evaporation are two ways in which a liquid changes into a gas.
Describe two differences between boiling and evaporation:
1. Boiling happens at a specific temperature.
2. Boiling has bubbles.

(ii) Name the change of state when:
A gas becomes a liquid: condensation
A solid becomes a gas: sublimation

1.1.4 Effect of Temperature and Pressure on Gases Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1:
Substances can change state.
- (i) Boiling and evaporation are two ways in which a liquid changes into a gas.
  Describe two differences between boiling and evaporation.
  1. ..........................................................................................................................................
  2. ..........................................................................................................................................
  [2]
- (ii) Name the change of state when:
  - A gas becomes a liquid: ................................................................................................
  - A solid becomes a gas: ................................................................................................
  [2]
Mark Scheme:
- (i):
  - Boiling happens at a specific temperature (1)
  - Boiling has bubbles (1)
- (ii):
  - A gas becomes a liquid: condensation (1)
  - A solid becomes a gas: sublimation (1)

1.1.2 Diffusion Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: The elements shown are gases at room temperature and pressure:
- Hydrogen
- Nitrogen
- Oxygen
- Chlorine
When separate samples of each of these gases are placed in a container, they will diffuse.
- (i) Describe why these gases diffuse.
  ....................................................................................................................................... [1]
- (ii) State which of these four gases has the highest rate of diffusion. Explain your answer.
  - Gas: ......................................................................................................................................
  - Explanation: ......................................................................................................................... ............................................................................................................................................. [2]

Mark Scheme:
- (i) random motion of molecules / particles. [1]
- (ii) Hydrogen:
  - lowest (relative) molecular mass. [2]

Solution

(i) Gases diffuse because of the random motion of molecules or particles.

(ii) Gas: Hydrogen
Explanation: Hydrogen has the lowest relative molecular mass, hence it diffuses faster.

Q2: The rate of diffusion of a gas was studied.

The following data shows the relative molecular masses (Mr) and rates of diffusion of the gases:

Gas	Temperature	rate of diffusion in cm3 / min
Nitrogen	25	1.00
Chlorine	25	0.63
Nitrogen	50	1.05

(i) Explain why nitrogen gas diffuses faster than chlorine gas.
....................................................................................................................................... [2]
(ii) Explain why the nitrogen gas diffuses faster at the higher temperature.
....................................................................................................................................... [1]

Mark Scheme:
- (i)
  - nitrogen has smaller Mr; [1]
  - nitrogen (molecules) move faster (than chlorine molecules) / ora. [1]
  - note: comparison must be made.
- (ii)
  - (at higher temperature) molecules move faster / have more energy. [1]

Solution

2.1.2 Atomic Structure Basics Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Atoms and ions are made from small particles called electrons, neutrons, and protons.

(a) Complete the table:

Particle	Relative Charge	Relative Mass
Electron	-1	1/1840
Neutron	_	_
Proton	_	_

(b) Complete the table for atoms and ions A, B, and C:

Atom or Ion	Number of Electrons	Number of Neutrons	Number of Protons	Symbol
A	18	_	20	⁴²₂₀Ca²⁺
B	_	18	_	³⁵₁₇Cl^1-
C	18	16	16

Mark Scheme:

(a):

Particle	Relative Charge	Relative Mass
Electron	-1	1/1840
Neutron	0	1
Proton	+1	1

(b):

Atom or Ion	Details
A	20 neutrons, Symbol: ⁴²₂₀Ca²⁺ [1]
B	17 protons, 18 neutrons, Symbol: ³⁵₁₇Cl [1]
C	16 protons, 16 neutrons, Symbol: S^2– [1]

2.1.2 Periodic Table Basics Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market disequilibrium. [2]
Mark Scheme:
- A market where demand and supply are not equal / balanced / matched (2).
- A market where there is a surplus / excess supply (1) or a shortage / excess demand (1).

2.3 Isotopes Basics Paper 4 IGCSE Chemistry Topic Questions

Q1 (a): Sulfur exists as a number of different isotopes. What is meant by the term isotopes?

Atoms with the same number of protons or atoms of the same element or atoms with the same atomic number [1]
Atoms with a different number of neutrons or atoms with a different mass number or atoms with a different nucleon number [1]

2.3 Isotopes Percentage Abundance Paper 4 IGCSE Chemistry Topic Questions

Question 1:
Table 2.2 shows the relative abundance of the two naturally occurring isotopes of copper.

Table 2.2

Isotope ⁶³Cu ⁶⁵Cu

Relative abundance 70% 30%

Calculate the relative atomic mass of copper to one decimal place.

Relative atomic mass = ................................................................. [2]
Mark Scheme:
- M1: (63 × 70) + (65 × 30) = 6360 (1)
- M2: 6360 / 100 = 63.6 (1)
[2]

Isotope	⁶³Cu	⁶⁵Cu
Relative abundance	70%	30%

2.4 Ions and Ionic Bonds Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Identify two determinants of price elasticity of demand. [2]
Mark Scheme:
- Availability of substitutes (1)
- Availability of complements (1)
- Proportion of income (1)
- Whether the product is a luxury or a necessity / essential (1)
- Whether it is addictive (1)
- Whether the purchase can be postponed (1)
- Impact of advertising / brand loyalty (1)

2.4.1 Ionic Compounds Physical Properties Paper 4 IGCSE Chemistry Topic Questions

Question Paper 1:
Give three physical properties of ionic compounds.
1. ..........................................................................................................................................
2. ..........................................................................................................................................
3. ..........................................................................................................................................
[3]
Mark Scheme:
- High melting point or boiling point
- Hard
- Brittle
- Soluble in water / insoluble in organic solvents
- Conduct electricity in liquid state or in aqueous solution
- Non-conductors or poor conductors (when solid)
[3]

2.5 Simple Molecules and covalent Compounds Dot Cross Diagrams Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Question: Complete the dot-and-cross diagram to show the arrangement of electrons in a molecule of ester Y.
Diagram:

Mark Scheme:

M1: Two crosses on the inner circle circumference labeled 'O' (up and down).
M2: Two dots on the inner circle circumference labeled 'C' (up and down).
M3: Correct arrangement of all other circles.

2.7 Metallic Bonding Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Describe the metallic bonding in zinc and then explain why it is a good conductor of electricity. [4]

Mark Scheme:

Positive ions / cations [1] (Not nuclei / atoms)
Delocalised / free / mobile or sea of electrons [1]
Bond is attraction between (positive) ions and delocalised electrons [1]
It is a good conductor because there are delocalised / free / mobile electrons [1] (Note: must indicate electrons are moving / carry charge)

2.6.1 Macromolecule Diamond / Graphite/ Silicon Dioxide Paper 4 IGCSE Chemistry Topic Questions

Question Paper 1:
Diamond and graphite are different solid forms of carbon. The carbon atoms in diamond and graphite are arranged in different ways.
- (a) State the number of covalent bonds each carbon atom has in diamond. [1]
- (b) State the term used to describe the structure of diamond. [1]
- (c) Name an oxide that has a similar structure to diamond. [1]
- (d) Describe the arrangement of atoms in graphite. [2]
- (e) Explain how graphite conducts electricity. [1]
Mark Scheme:
- (a): 4 (1)
- (b): Giant covalent (1)
- (c): Silicon dioxide (1)
- (d):
  - M1: Layers
  - M2: Hexagonal (rings of carbon) [2]
- (e): Mobile electrons (1)

2.7 Metallic Bonding Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Describe the metallic bonding in zinc and then explain why it is a good conductor of electricity. [4]

Mark Scheme:

Positive ions / cations [1] (Not nuclei / atoms)
Delocalised / free / mobile or sea of electrons [1]
Bond is attraction between (positive) ions and delocalised electrons [1]
It is a good conductor because there are delocalised / free / mobile electrons [1] (Note: must indicate electrons are moving / carry charge)

3.1 / Molecular Formular and Empirical Formula Paper 4 IGCSE Chemistry Topic Questions

Q1: Magnesium phosphate contains magnesium ions, Mg²⁺, and phosphate ions, PO₄^3–. Deduce the formula of magnesium phosphate. [1]

Mark Scheme:
- Mg₃(PO₄)₂ [1]

Solution

Magnesium ion: Mg²⁺ (charge +2), Phosphate ion: PO₄^3– (charge -3).
To balance charges, the total positive charge must equal the total negative charge.
3 × (+2) = +6 (from 3 Mg²⁺) and 2 × (–3) = –6 (from 2 PO₄^3–).
Hence, the formula of magnesium phosphate is Mg₃(PO₄)₂.

Alternatively, the charges on the top right of ions become the subscript of the opposite ions, while creating the formula for the compound

Q2: Sulfur dioxide reacts with aqueous sodium sulfite to produce a compound with the following composition by mass: 29.1% Na, 40.5% S and 30.4% O. Calculate the empirical formula of this compound. Empirical formula = .............................. [3]

Mark Scheme:
- 29.1 / 23, 40.5 / 32, 30.4 / 16 or 1.2(65), 1.2(65), 1.9 [1]
- 1:1:1.5 [1]
- Empirical formula: Na₂S₂O₃ [1]

Solution

Step 1: Divide each percentage by the relative atomic mass (Ar):
Na: 29.1 / 23 ≈ 1.27, S: 40.5 / 32 ≈ 1.27, O: 30.4 / 16 ≈ 1.9.
Step 2: Simplify the ratio by dividing by the smallest decimal[1.27]:
1.27 : 1.27 : 1.9 ≈ 1 : 1 : 1.5.
Step 3: Multiply through to remove fractions (×2):
2 : 2 : 3.
Therefore, the empirical formula is Na₂S₂O₃.

Q3:
- (a) Compound X has the following composition by mass: H, 3.66%; P, 37.80%; O, 58.54%.
- Calculate the empirical formula of compound X. empirical formula = .............................. [2]
- (b) Compound Y has the empirical formula H₃PO₄ and a relative molecular mass of 98.
- Deduce the molecular formula of compound Y. molecular formula = .............................. [1]

Mark Scheme:
- (a) M1: H = 3.66 / 1, P = 37.80 / 31, O = 58.54 / 16 OR H = 3.66, P = 1.22, O = 3.66 OR H:P:O = 3:1:3 [1]
- M2: H₃PO₃ [1]
- (b): H₃PO₄ [1]

Solution

(a) Divide by Ar: H = 3.66 / 1 ≈ 3.66, P = 37.80 / 31 ≈ 1.22, O = 58.54 / 16 ≈ 3.66.
Simplify ratio: H:P:O ≈ 3:1:3.
Therefore, the empirical formula is H₃PO₃.

(b) Relative molecular mass = 98. Empirical formula mass = 98 (H₃PO₄).
Since they match, the molecular formula is H₃PO₄.

3.1.2 /Formula of Ions and Compounds Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Magnesium phosphate contains magnesium ions, Mg²⁺, and phosphate ions, PO₄^3–. Deduce the formula of magnesium phosphate. [1]

Mark Scheme:

Mg₃(PO₄)₂ [1]

Solution

Magnesium ion has a charge of +2 (Mg²⁺), and the phosphate ion has a charge of -3 (PO₄^3–).

To deduce the formula of magnesium phosphate, the total positive charge from the magnesium ions must balance the total negative charge from the phosphate ions.

Step 1: Find the least common multiple (LCM) of the charges (+2 and -3), which is **6**.
Step 2: Determine the number of each ion needed to achieve a neutral compound:

**3 magnesium ions** contribute a total charge of 3 × +2 = +6.
**2 phosphate ions** contribute a total charge of 2 × -3 = -6.

Step 3: Combine the ions to form a neutral compound:
Mg₃(PO₄)₂.

Hence, the formula of magnesium phosphate is Mg₃(PO₄)₂.

3.2 Word Equations and Symbol Equations Paper 4 IGCSE Chemistry Topic Questions

Q1: Element X is a Group III metal. It burns in air to form an oxide X₂O₃.
Write a symbol equation for this reaction.
.............................................................................................................................................. [2]

Mark Scheme:

Formulae [1]
Balance, 4X + 3O₂ → 2X₂O₃ [1]

Q2: Complete the word equation for this reaction.

Sodium bromide + Chlorine → .............................. + ..............................

Mark Scheme:

calcium oxide (1)
carbon dioxide (1)

3.2 Ionic Equations Paper 4 IGCSE Chemistry Topic Questions

Q1:
- Aqueous silver nitrate is added to aqueous magnesium chloride.
- A white precipitate forms.
- Write an ionic equation for this reaction. Include state symbols.
- ...............................................................................................................................
- ...............................................................................................................................
- ............................................................................................................................... [2]

Mark Scheme:
- Formulae: Ag⁺(aq) + Cl^-(aq) → AgCl(s) [1]
- State Symbols: Correct state symbols included [1]

Solution

Step 1: Write the full balanced molecular equation.
AgNO₃(aq) + MgCl₂(aq) → AgCl(s) + Mg(NO₃)₂(aq)
Step 2: Split all strong electrolytes into ions (complete ionic equation).
Ag⁺(aq) + NO₃^-(aq) + Mg²⁺(aq) + 2Cl^-(aq) → AgCl(s) + Mg²⁺(aq) + 2NO₃^-(aq)
Step 3: Identify and cancel out the spectator ions.
Spectator ions: NO₃^-(aq) and Mg²⁺(aq)
Step 4: Write the net ionic equation.
Ag⁺(aq) + Cl^-(aq) → AgCl(s)

3.3 Calculating Moles/ Concentration Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources <

Question: The equation for the reaction is shown:

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

Calculate the concentration of NaOH(aq) formed, in g/dm³, when 0.345 g of sodium is added to 50.0 cm³ of distilled water. Assume there is no change in volume.

Use the following steps:

● Calculate the number of moles of Na added.
= .............................. mol
● Determine the number of moles of NaOH formed.
= .............................. mol
● Calculate the concentration of NaOH in mol/dm³.
concentration of NaOH = .............................. mol/dm³
● Determine the Mr of NaOH and calculate the concentration of NaOH in g/dm³.
concentration of NaOH = .............................. g/dm³

Mark Scheme:

M1: mol Na = 0.345 / 23 = 0.015(00) (1)
M2: mol NaOH = M1 = 0.015(00) (1)
M3: M2 × 1000 / 50 = 0.015(00) × 20 = 0.3(00) (1)
M4: Mr NaOH = 40 (1)
M5: M4 × M3 = 40 × 0.3 = 12.(0) (g/dm³) (1)

Question: The equation for the reaction is shown:
2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

Calculate the concentration of NaOH(aq) formed, in g/dm³, when 0.345 g of sodium is added to 50.0 cm³ of distilled water. Assume there is no change in volume.
Use the following steps:
● Calculate the number of moles of Na added.
= .............................. mol
● Determine the number of moles of NaOH formed.
= .............................. mol
● Calculate the concentration of NaOH in mol/dm³.
concentration of NaOH = .............................. mol/dm³
● Determine the M_r of NaOH and calculate the concentration of NaOH in g/dm³.
concentration of NaOH = .............................. g/dm³

Mark Scheme:
- M1: mol Na = 0.345 / 23 = 0.015(00) (1)
- M2: mol NaOH = M1 = 0.015(00) (1)
- M3: M2 × 1000 / 50 = 0.015(00) × 20 = 0.3(00) (1)
- M4: M_r NaOH = 40 (1)
- M5: M4 × M3 = 40 × 0.3 = 12.(0) g/dm³ (1)

Solution

Step 1: Calculate the number of moles of Na added.
Number of moles = mass / Ar = 0.345 g / 23 = 0.015 mol.

Step 2: Determine the number of moles of NaOH formed.
From the balanced equation, 2 mol of Na produces 2 mol of NaOH.
Therefore, moles of NaOH = moles of Na = 0.015 mol.

Step 3: Calculate the concentration of NaOH in mol/dm³.
Concentration = moles × (1000 / volume in cm³).
Volume = 50.0 cm³, so:
Concentration = 0.015 × (1000 / 50) = 0.3 mol/dm³.

Step 4: Determine the M_r of NaOH and calculate the concentration in g/dm³.
M_r of NaOH = 23 (Na) + 16 (O) + 1 (H) = 40.
Concentration in g/dm³ = M_r × concentration in mol/dm³.
= 40 × 0.3 = 12.0 g/dm³.

Therefore, the concentration of NaOH is 12.0 g/dm³.

3.3 Molar Gas Volume Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Calculate the volume of oxygen, measured at r.t.p., which is formed when 1.60 g of CuO reacts as shown in the equation:

4CuO → 2Cu₂O + O₂
Volume: .................................................... dm³ [3]

Mark Scheme:

M1: mol CuO = (1.60 ÷ 80) = 0.02(00) mol [1]
M2: mol O₂ = (M1 ÷ 4 = 0.02 ÷ 4) = 0.005(00) mol [1]
M3: vol O₂ = M2 × 24.0 = 0.005 × 24.0 = 0.12(0) dm³ [1]

Solution

Step 1: Calculate the moles of CuO.
Moles of CuO = Mass ÷ Molar Mass = 1.60 ÷ 80 = 0.0200 mol

Step 2: Use the equation to find moles of O₂.
From the equation, 4 mol of CuO produces 1 mol of O₂.
Moles of O₂ = Moles of CuO ÷ 4 = 0.0200 ÷ 4 = 0.00500 mol

Step 3: Calculate the volume of O₂ at r.t.p.
Volume of O₂ = Moles × 24.0 dm³
Volume of O₂ = 0.00500 × 24.0 = 0.120 dm³

Final Answer: 0.12 dm³

3.4 Excess / Limiting Reactants Paper 4 IGCSE Chemistry Topic Questions

Q1: Propanol reacts with methanoic acid to form the ester propyl methanoate.

CH₃CH₂CH₂OH + HCOOH → HCOOCH₂CH₂CH₃ + H₂O
4.0 g of methanoic acid was reacted with 6.0 g of propanol.
(i) Calculate the Mr of methanoic acid = ........................................ [1]
(ii) Calculate the Mr of propanol = ........................................ [1]
(iii) Determine which one is the limiting reagent. Show your reasoning.
.............................................................................................................................................
.............................................................................................................................................
............................................................................................................................................. [2]

Mark Scheme:

(i): 46 [1]
(ii): 60 [1]
(iii): moles of CH₃CH₂CH₂OH = 0.1; methanoic acid is the limiting reagent [1]

Solution

(i) Calculate the Mr of methanoic acid (HCOOH):
Mr = (1 × H) + (1 × C) + (2 × O) + (1 × H) = 46
Answer: 46

(ii) Calculate the Mr of propanol (CH₃CH₂CH₂OH):
Mr = (3 × C) + (8 × H) + (1 × O) + (1 × H) = 60
Answer: 60

(iii) Determine the limiting reagent:
Moles of propanol = Mass ÷ Mr = 6.0 ÷ 60 = 0.1 mol
Moles of methanoic acid = Mass ÷ Mr = 4.0 ÷ 46 ≈ 0.087 mol

Since methanoic acid has fewer moles (0.087 mol) compared to propanol (0.1 mol), methanoic acid is the limiting reagent.

Final Answer: Methanoic acid is the limiting reagent.

3.5 Percentage Yield / Percent by Mass Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1:

5.95 g of cobalt(II) carbonate were added to 40 cm³ of hydrochloric acid, concentration 2.0 mol/dm³.
Calculate the maximum yield of cobalt(II) chloride-6-water and show that the cobalt(II) carbonate was in excess.
The equations are:

CoCO₃ + 2HCl → CoCl₂ + CO₂ + H₂O
CoCl₂ + 6H₂O → CoCl₂·6H₂O

Maximum yield:

Number of moles of HCl used = ........................................
Number of moles of CoCl₂ formed = ........................................
Number of moles of CoCl₂·6H₂O formed = ........................................
Mass of one mole of CoCl₂·6H₂O = 238 g
Maximum yield of CoCl₂·6H₂O = ........................................ g

Mark Scheme:

M1: Number of moles of HCl used = 0.04 × 2 = 0.08 [1]
M2: Number of moles CoCl₂ formed = 0.04 [1]
M3: Number of moles CoCl₂·6H₂O formed = 0.04 [1]
M4: Maximum yield of CoCl₂·6H₂O = 9.52 g [1]
Allow: 9.5 g [ECF allowed on moles of HCl].

Solution
Step 1: Calculate the number of moles of HCl used.
The volume of HCl is 40 cm³ (0.04 dm³) and the concentration is 2.0 mol/dm³.
Moles of HCl = concentration × volume = 2.0 × 0.04 = 0.08 mol.
Step 2: Determine the moles of CoCl₂ formed.
From the balanced equation:
CoCO₃ + 2HCl → CoCl₂ + CO₂ + H₂O
2 moles of HCl react to form 1 mole of CoCl₂.
Moles of CoCl₂ = 0.08 ÷ 2 = 0.04 mol.
Step 3: Moles of CoCl₂·6H₂O formed.
From the equation:
CoCl₂ + 6H₂O → CoCl₂·6H₂O
1 mole of CoCl₂ forms 1 mole of CoCl₂·6H₂O.
Therefore, moles of CoCl₂·6H₂O = 0.04 mol.
Step 4: Calculate the mass of CoCl₂·6H₂O.
Mass = moles × molar mass
Mass = 0.04 × 238 = 9.52 g.
Conclusion:
The maximum yield of CoCl₂·6H₂O is 9.52 g. The cobalt(II) carbonate is in excess since only 0.08 mol of HCl was used up.

4.1 Electrolysis Basics Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Electrode Question

Q1:
- a State two reasons why carbon (graphite) is suitable to use as an electrode.[2]
- Current Flow Question
  b Name the particle responsible for the conduction of electricity in the metal wires used in a circuit.[1]

Mark Scheme:
- a
  - M1 inert (1)
  - M2 good conductor of electricity (1)
  [2]
- b electron [1]

4.1.3 Electrolysis of Molten Compounds Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Molten potassium bromide can be electrolysed. Predict the products of this electrolysis at:
the anode ..................................................................................................................................
the cathode .............................................................................................................................. [2].
Mark Scheme:
the anode: bromine / Br₂ ................................................................................................................. 1
the cathode: potassium / K ...................................................................................................................... [1].

4.1.4.1 Electrolysis of Aqueous Compounds [ Concentrated] Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Question 1: This question is about electrolysis.

Concentrated hydrochloric acid is electrolysed using the apparatus shown.[ DIgram has not been included here. KIndly refer to tghe paper 0620_w21_qp_41-q3]
(a) Chloride ions are discharged at the anode.
- (i) Complete the ionic half-equation for this reaction.
  .......... Cl^–(aq) → ..........(g) + .......... e^– [2]
- (ii) State whether oxidation or reduction takes place. Explain your answer.
  ..................................................................................................................
  .................................................................................................................. [1]
(b) Describe what is seen at the cathode.
..................................................................................................................
.................................................................................................................. [1]
(c) Write the ionic half-equation for the reaction at the cathode.
..................................................................................................................
.................................................................................................................. [2]
(d) The pH of the electrolyte is measured throughout the experiment.
- (i) Suggest the pH of the electrolyte at the beginning of the experiment.
  .................................................................................................................. [1]
- (ii) State how the pH changes, if at all, during the experiment.
  Explain your answer.
  ..................................................................................................................
  ..................................................................................................................
  .................................................................................................................. [2]

Mark Scheme:

3(a)(i):
- 2Cl ^– → Cl ₂ + 2e^– (1)
- Rest of the equation (1)
- Total: 2
3(a)(ii):
- Oxidation AND lose electrons (1)
- Total: 1
3(b):
- Effervescence (of colourless gas) (1)
- Total: 1
3(c):
- 2H⁺ + 2e^– → H₂
- H⁺ + e^– as the only species on LHS (1)
- Rest of the equation fully correct (1)
- Total: 2
3(d)(i):
- (1)
- Total: 1
3(d)(ii):
- M1: Increase (1)
- M2: H⁺ ions being removed (1)
- Total: 2

4.1.4.2 Electrolysis of Aqueous Compounds [ Dilute] Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: A student carries out an electrolysis experiment using the apparatus shown.
- [Diagram not included here. But it has two carbon electrodes and dilute aqueous sodium chloride as the electrolyte. Diagram can be found at: 0620/42/M/J/21-q4]
- The student uses dilute aqueous sodium chloride.
  - (a) State the name given to any solution which undergoes electrolysis.
    .............................................................................................................................................. [1]
  - (b) Hydroxide ions are discharged at the anode.
    - (i) Complete the ionic half-equation for this reaction.
      ..........OH–(aq) → ........................... + O2 (g) + 4e– [2]
    - (ii) Explain how the ionic half-equation shows the hydroxide ions are being oxidised.
      ....................................................................................................................................... [1]
  - (c) Describe what the student observes at the cathode.
    .............................................................................................................................................. [1]
  - (d) Write the ionic half-equation for the reaction at the cathode.
    .............................................................................................................................................. [2]

Mark Scheme:
- (a) electrolyte [1]
- (b)(i) 4OH⁻ → 2H₂O + O₂ + 4e⁻
  - balance of charge (1)
  - rest of equation (1)
  [2]
- (b)(ii) (OH⁻(aq) ions) lose electrons [1]
- (c) fizzing [1]
- (d) 2H⁺ + 2e⁻ → H₂
  - species correct (1)
  - fully correct equation (1)
  [2]

4.1.5 Electrolysis of Brine Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Brine is concentrated aqueous sodium chloride.
(i) Name three substances which are manufactured by passing electricity through brine.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
3 .......................................................................................................................................... [3]
Mark Scheme:
(i) hydrogen
chlorine
sodium hydroxide ................................................................................................................. 3
4(e)(ii) sodium ...................................................................................................................... 1

4.1.6 Electrolysis of Dilute Sulfuric Acid Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1:
(a) Dilute sulfuric acid is electrolysed using the apparatus shown in the diagram.
(i) State what is meant by the term electrolysis.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii) Explain why inert electrodes are used.
.............................................................................................................................................
....................................................................................................................................... [1]
(iii) Name the products formed at each electrode.
negative electrode ..............................................................................................................
positive electrode ................................................................................................................ [2]
(iv) Write an ionic half‑equation for the reaction at the negative electrode.
....................................................................................................................................... [2]
Mark Scheme:
(a)(i) breakdown by (the passage of) electricity (1)
of an ionic compound in molten/aqueous (state) (1) ................................................................................. 2
(a)(ii) they do not react ...................................................................................................................... 1
(a)(iii) negative electrode: hydrogen (gas) (1)
positive electrode: oxygen (gas) (1)
(a)(iv) H⁺ + e^- as the only species on the left (1)
equation fully correct (1) ...................................................................................................................... 2
2H⁺ + 2e^- → H₂ (scores 2)

4.1.7 Electrolysis of Copper Sulfate Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Qp1:
Copper has the structure of a typical metal. It has a lattice of positive ions and a “sea” of mobile electrons. The lattice can accommodate ions of a different metal.
(a) Aqueous copper(II) sulphate solution can be electrolysed using carbon electrodes. The ions present in the solution are as follows.
Cu²⁺(aq), SO₄^2-(aq), H⁺(aq), OH^-(aq)
(i) Write an ionic equation for the reaction at the negative electrode (cathode).
(ii) A colourless gas was given off at the positive electrode (anode) and the solution changes from blue to colourless.
Explain these observations.
(b) Aqueous copper(II) sulphate can be electrolysed using copper electrodes. The reaction at the negative electrode is the same but the positive electrode becomes smaller and the solution remains blue.
(i) Write a word equation for the reaction at the positive electrode.
(ii) Explain why the colour of the solution does not change.
(iii) What is the large scale use of this electrolysis?
Mark Scheme:
(a) (i) Cu²⁺ + 2e^- = Cu [1]
(ii) gas is oxygen [1]
(copper(II) sulphate) changes to sulphuric acid
or copper ions removed from solution [1]
(b) (i) copper atoms - electrons = copper ions
accept correct symbol equation [1]
(ii) concentration of copper ions does not change or
amount or number of copper ions does not change [1]
copper ions are removed and then replaced
or copper is transferred from anode to cathode [1]
(iii) refining copper or plating (core)
or extraction of boulder copper [1]

4.1.7 Electrolysis -Mixed Bag [ Mutiple Concepts Tested in One Question] Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Question Paper:

The results of experiments on electrolysis using inert electrodes are given in the table.
Complete the table; the first line has been completed as an example.

electrolyte	change at negative electrode	change at positive electrode	change to electrolyte
molten lead(II) bromide	lead formed	bromine formed	used up
.......................................	potassium formed	iodine formed	used up
dilute aqueous sodium chloride	.......................................	.......................................	.......................................
aqueous copper(II) sulfate	.......................................	.......................................	.......................................
.......................................	hydrogen formed	bromine formed	potassium hydroxide formed

Mark Scheme:
- molten potassium iodide NOT aqueous [1]
- hydrogen [1]
- oxygen [1]
- water used up or solution becomes more concentrated or sodium chloride remains
- NOT no change
- If products are given as hydrogen, chlorine and sodium hydroxide then 2/3
- copper [1]
- oxygen (and water) [1]
- sulfuric acid accept hydrogen sulfate [1]
- aqueous or dilute or concentrated potassium bromide [1]
- accept correct formulae

4.1.8 Construct Ionic Half Equations Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Electrolysis is carried out on aluminium oxide dissolved in molten cryolite.
Write the ionic half-equation for the reaction occurring at the negative electrode. [2]
Mark Scheme:
(ii) Al³⁺ + 3e^- → Al
M1 only Al³⁺ + (3) e^- on the left [1]
M2 equation fully correct [1]

4.1.9 Electroplating Paper 4 IGCSE Chemistry Topic Questions

Q1:

Q1: One of the methods used to prevent iron or steel from rusting is to electroplate it with another metal, such as tin. Complete the following:
The anode is made of ................................................. .
The cathode is made of ................................................. .
The electrolyte is a solution of ............................................ [3]

Mark Scheme:
- Anode: tin (NOT impure tin) [1]
- Cathode: iron or steel [1]
- Electrolyte: tin salt or tin ions as electrolyte (NOT oxide, hydroxide, or carbonate) [1]

Solution

The anode: The anode is made of tin because during electroplating, the anode supplies the metal ions that are deposited onto the cathode.

The cathode: The cathode is made of iron or steel. This is the object to be coated with tin in the process.

The electrolyte: The electrolyte is a solution containing tin ions, such as tin chloride (SnCl₂) or tin sulfate (SnSO₄). The tin ions migrate towards the cathode and are deposited as a thin layer of tin.

Q2: A metal spoon is electroplated with copper. State what is used as:
The positive electrode (anode) ......................................................................................
The negative electrode (cathode) ...................................................................................
The electrolyte ................................................................................................................... [3]

Mark Scheme:
- Positive electrode (anode): copper [1]
- Negative electrode (cathode): spoon [1]
- Electrolyte: aqueous solution of a named copper salt (e.g., copper sulfate) [1]

Solution

The positive electrode (anode): The anode is made of copper. The copper atoms at the anode lose electrons (oxidation) to form copper ions (Cu²⁺), which enter the solution.

The negative electrode (cathode): The cathode is the metal spoon. The copper ions (Cu²⁺) from the electrolyte migrate to the spoon and gain electrons (reduction) to form solid copper, coating the spoon.

The electrolyte: The electrolyte is an aqueous solution of a copper salt, such as copper sulfate (CuSO₄). This provides the copper ions needed for electroplating.

4.2 Hydrogen-Oxygen Fuel Cells Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Hydrogen–oxygen fuel cells can be used to produce electricity in vehicles.

(i) Write the symbol equation for the overall reaction in a hydrogen–oxygen fuel cell.
.............................................................................................................................................. [2]
(ii) State one advantage of using hydrogen–oxygen fuel cells instead of petrol in vehicle engines.
.............................................................................................................................................. [1]

Mark Scheme:

(i) 2H₂ + O₂ → 2H₂O

M1 all formulae [1]
M2 equation correct [1]

(ii) no carbon dioxide evolved; OR more efficient [1]

5.1.1 Endothermic / Exothermic Reactions Basics Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: This question is about fuels and energy production.
- (a) Chemical reactions can be endothermic or exothermic.
- State the meaning of the term endothermic.
- ....................................................................................................................................................
- .............................................................................................................................................. [1]

Mark Scheme:
- Reaction which absorbs thermal energy / reaction which absorbs heat [1]

Solution

Reaction which absorbs thermal energy
[OR] Reaction which absorbs heat.

5.1.3 Enthalpy Change and Bond Energy Calculation Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Chloroethene (CH₂=CHCl) can be manufactured from 1,2-dichloroethane (CH₂ClCH₂Cl).
The equation can be represented as shown:

    Cl      H
     |      |
H — C — C — H   →   H — C = C — H   +   H — Cl
     |      |               |
    H      Cl              Cl

Some bond energies are given:
- C—C: 350 kJ/mol
- C=C: 610 kJ/mol
- C—Cl: 340 kJ/mol
- C—H: 410 kJ/mol
- H—Cl: 430 kJ/mol
Use the bond energies in the table to calculate the energy change, in kJ/mol, of the reaction.
Use the following steps:
- Calculate the energy needed to break bonds.
- Calculate the energy released when bonds form.
- Calculate the energy change of the reaction.

Mark Scheme:
M1: 2670 (1)
M2: 2610 (1)
M3: (+) 60 (1)

Solution

Step 1: Energy needed to break bonds
Bonds broken in CH₂ClCH₂Cl:
- 1 × C—C = 350 kJ/mol
- 4 × C—H = 4 × 410 = 1640 kJ/mol
- 2 × C—Cl = 2 × 340 = 680 kJ/mol
Total energy needed = 350 + 1640 + 680 = 2670 kJ/mol

Step 2: Energy released when bonds form
Bonds formed in H—C=CH + HCl:
- 1 × C=C = 610 kJ/mol
- 2 × C—H = 2 × 410 = 820 kJ/mol
- 1 × H—Cl = 430 kJ/mol
Total energy released = 610 + 820 + 430 = 2610 kJ/mol

Step 3: Energy change of the reaction
Energy change = Energy needed to break bonds – Energy released when bonds form
= 2670 – 2610 = +60 kJ/mol.

Therefore, the energy change of the reaction is +60 kJ/mol.

6.1 Physical and Chemical Change Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.2 effect of changing the concentration of solutions on the rate of reaction Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.2 effect on the rate of reaction of changing the pressure of gases Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.2 effect on the rate of reaction of changing the surface area of solids Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.2 effect on the rate of reaction of changing the temperature Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.2 effect on the rate of reaction of adding or removing a catalyst, including enzymes Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.2 Investigating Rate of Reaction Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.3.1 Reversible Reactions Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.3.2 Effect of Temperature on Equilibrium in a Reversible Reaction Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.3.2 Effect of Pressure on Equilibrium in a Reversible Reaction Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.3.2 Effect of Concentration on Equilibrium in a Reversible Reaction Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.3.2 Effect of Catalyst on Equilibrium in a Reversible Reaction Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.3.2 Effect of water and heat on the Reversible Reaction of Copper Sulfate and Cobalt Chloride Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

6.3.2 Haber's Process Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Nitrogen reacts with hydrogen to form ammonia, NH₃, in the Haber process.
- State the essential conditions in the Haber process.
- Write an equation for the chemical reaction.
- ....................................................................................................................................................
  ....................................................................................................................................................
  ....................................................................................................................................................
  ....................................................................................................................................................
  ....................................................................................................................................................
- [4]
Mark Scheme:
- 450 °C (1)
- 200 atmospheres (1)
- Iron (catalyst) (1)
- N₂ + 3H₂ ⇌ 2NH₃ (1)

Solution

The essential conditions in the Haber process are a temperature of 450°C, a pressure of 200 atmospheres, and the use of iron as a catalyst. The equation for the chemical reaction is: N₂ + 3H₂ ⇌ 2NH₃.

6.3.2 Contact Process Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Sulfuric acid is manufactured by an industrial process. Sulfur is obtained from sulfur-containing metal ores.
The sulfur in the metal ore is converted to sulfur dioxide which is then oxidised to sulfur trioxide as shown.
2SO₂(g) + O₂(g) → 2SO₃(g)
- (a) Name a metal ore which contains sulfur.
  .............................................................................................................................................. [1]
- (b) Describe the process which converts metal ores to sulfur dioxide.
  .............................................................................................................................................. [1]
- (c) Name the industrial process used to manufacture sulfuric acid.
  .............................................................................................................................................. [1]
- (d) The reaction that produces sulfur trioxide is an equilibrium. The forward reaction is exothermic.
  - (i) State the temperature and pressure used to make sulfur trioxide.
    temperature = .............................. °C
    pressure = .............................. atm [2]
  - (ii) Name the catalyst used.
    ....................................................................................................................................... [1]
  - (iii) Describe two features of an equilibrium.
    1 ..........................................................................................................................................
    2 .......................................................................................................................................... [2]
  - (iv) State the effect, if any, on the position of equilibrium when the following changes are made. Explain your answers.
    - temperature is increased
      ....................................................................................................
      .............................................................................................................................................
    - pressure is increased
      .......................................................................................................
      ............................................................................................................................................. [4]
- Explain, in terms of particles, what happens to the rate of reaction when the temperature is increased.
  .............................................................................................................................................
  .............................................................................................................................................
  .............................................................................................................................................
  .............................................................................................................................................
  ....................................................................................................................................... [3]

Mark Scheme:
- (a) zinc blende [1]
- (b) strong heating in air / roasting in air [1]
- (c) contact [1]
- (d)(i)
  - M1 450 °C (1)
  - M2 1–2 atm (1)
  [2]
- (d)(ii) vanadium(V) oxide [1]
- (d)(iii)
  - M1 the rate of forward reaction equals (the rate of the) reverse reaction (1)
  - M2 concentrations of reactants and products are constant (1)
  [2]
- (d)(iv)
  - Increased temperature:
    - M1 (position of) equilibrium moves to left-hand side (1)
    - M2 reaction is exothermic (1)
  - Increased pressure:
    - M3 (position of) equilibrium moves to right-hand side (1)
    - M4 more (gaseous) moles/molecules on left-hand side (1)
  [4]

Solution

(a) The metal ore which contains sulfur is zinc blende.

(b) The process which converts metal ores to sulfur dioxide is strong heating in air or roasting in air.

(c) The industrial process used to manufacture sulfuric acid is the contact process.

(d)(i) The temperature used to make sulfur trioxide is 450°C, and the pressure is 1–2 atm.

(d)(ii) The catalyst used is vanadium(V) oxide.

(d)(iii) Two features of an equilibrium are:
1. The rate of forward reaction equals the rate of the reverse reaction.
2. The concentrations of reactants and products are constant.

(d)(iv) When the temperature is increased, the position of equilibrium moves to the left-hand side because the reaction is exothermic.
When the pressure is increased, the position of equilibrium moves to the right-hand side because there are more gaseous molecules on the left-hand side.

When the temperature is increased, the rate of reaction increases because particles have more energy, leading to more frequent and successful collisions.

6.3.2 Redox Reaction Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: Iron is extracted from its ore, hematite, in the blast furnace.
Describe the reactions involved in this extraction. Include one equation for a redox reaction and one for an acid/base reaction.
[5]

Mark Scheme:
- One redox equation from: [1]
  - Fe₂O₃ + 3CO → 2Fe + 3CO₂
  - 2Fe₂O₃ + 3C → 4Fe + 3CO₂
  - Fe₂O₃ + 3C → 2Fe + 3CO
  - C + O₂ → CO₂
  - CO₂ + C → 2CO
- One acid/base equation: [1]
  - CaO + SiO₂ → CaSiO₃
  - CaCO₃ + SiO₂ → CaSiO₃ + CO₂
- Any three additional equations or comments from: [3]
  - carbon burns or reacts to form carbon dioxide;
  - this reaction is exothermic or produces heat;
  - carbon dioxide is reduced to carbon monoxide;
  - carbon monoxide reduces hematite to iron;
  - carbon reduces hematite to iron;
  - limestone removes silica to form slag;
  - limestone decomposes;

6.3.2 Oxidation Reduction Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1: When copper(II) oxide is heated at 800 °C, it undergoes the reaction shown by the equation:
```
        4CuO → 2Cu2O + O2
        
```
- (i) Identify the changes in oxidation numbers of copper and oxygen in this reaction.
- Explain in terms of changes in oxidation numbers why this is a redox reaction.
- Change in oxidation number of copper: from …………… to ……………
- Change in oxidation number of oxygen: from …………… to ……………
- Explanation ..........................................................................................................
- ...................................................................................................................................... [3]

Mark Scheme:
- Copper: +2 to +1 [1]
- Oxygen: –2 to 0 [1]
- Explanation: Reduction and oxidation both occur (redox reaction) [1]

Solution

Step 1: Identify changes in oxidation numbers
- The oxidation number of copper in CuO is **+2**.
- The oxidation number of copper in Cu₂O is **+1**.
- The oxidation number of oxygen in CuO is **–2**, and in O₂, it is **0**.

Step 2: Explain why this is a redox reaction
- Copper is **reduced** because its oxidation number decreases from **+2 to +1**.
- Oxygen is **oxidised** because its oxidation number increases from **–2 to 0**.
- Since both oxidation (loss of electrons) and reduction (gain of electrons) occur, this is a **redox reaction**.

6.3.2 Oxidising and Reducing Agent Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1:
- The reactivity series shows the metals in order of reactivity.
- (a) The reactivity series can be established using displacement reactions.
- A piece of zinc is added to aqueous lead nitrate. The zinc becomes coated with a black deposit of lead.
Zn + Pb²⁺ → Zn²⁺ + Pb
Zinc is more reactive than lead.
The reactivity series can be written as a list of ionic equations:

...... → ...... + ...... (most reactive metal: the best reductant)
Zn → Zn²⁺ + 2e
Fe → Fe²⁺ + 2e
Pb → Pb²⁺ + 2e
Cu → Cu²⁺ + 2e
Ag → Ag⁺ + e^–

(i) Explain why the positive ions are likely to be oxidants (oxidising agents).

.............................................................................................................................. [1]

(ii) Deduce which ion is the best oxidant (oxidising agent).

.............................................................................................................................. [1]

(iii) Which ion(s) in the list can oxidise lead metal?

.............................................................................................................................. [1]

Mark Scheme:
- (i) Because they can accept or gain electrons / change into atoms or can be reduced [1]
- (ii) Ag⁺ or silver [1] (charge not essential but if given, it must be correct)
- (iii) Ag⁺ and Cu²⁺ or silver and copper [1]

Solution

(i) Because they can accept or gain electrons or can be reduced.
(ii) Ag⁺ (or silver).
(iii) Ag⁺ and Cu²⁺ (or silver and copper).

7.1.1 Effect of Indicators [ litmus, thymolphthalein and methyl orange on Acids Paper 4 IGCSE Chemistry Topic Questions

View All Member Area Resources

Q1:
- (i) Describe how universal indicator can be used to find the pH of an acidic solution.
- ....................................................................................................................................................
- ....................................................................................................................................................
- .................................................................................................................................................... [2]

Mark Scheme:
- M1: Add indicator (paper) to acid / solution [1]
- M2: Compare colour with indicator colour chart / (pH) colour chart [1]

Solution

Add universal indicator (or indicator paper) to the acidic solution.
[OR] Dip universal indicator paper into the solution.

Compare the colour change of the indicator with the colours shown on the pH chart.
The colour will indicate the pH value of the acidic solution.

Q1: A student determines the concentration of a solution of dilute sulfuric acid, H₂SO₄, by titration with aqueous sodium hydroxide, NaOH.
- Step 1: 25.0 cm³ of 0.200 mol/dm³ NaOH is transferred into a conical flask.
- Step 2: Three drops of methyl orange indicator are added to the conical flask.
- Step 3: A burette is filled with H₂SO₄.
- Step 4: The acid in the burette is added to the conical flask until the indicator changes colour. The volume of acid is recorded. This process is known as titration.
- Step 5: The titration is repeated several times until a suitable number of results is obtained.

Mark Scheme:
- Indicator changes colour: yellow to orange [1]

Solution

During the titration, the methyl orange indicator changes colour from yellow to orange as the acid is added to the sodium hydroxide solution.

8.5 Noble Gases Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

9.1 Properties of Metals Paper 4 IGCSE Chemistry Topic Questions

Q1:

This question is about zinc and compounds of zinc.
(a) Zinc is a metal. Give three physical properties of metals.
1 ................................................................................................................................................
2 ................................................................................................................................................
3 ................................................................................................................................................
[3]

Mark Scheme:
- Conduct electricity or conduct heat [1]
- Malleable [1]
- Ductile [1]
- Shiny or lustrous [1]

Solution

1. Conduct electricity or conduct heat
2. Malleable
3. Ductile
4. Shiny or lustrous

9.2.1 Uses of Metals [ Copper and Aluminium] Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

9.3 Alloys Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

9.4 Reactivity Series Paper 4 IGCSE Chemistry Topic Questions

Q1: The reactivity series shows the metals in order of reactivity.
- (a) The reactivity series can be established using displacement reactions.
  - A piece of zinc is added to aqueous lead nitrate. The zinc becomes coated with a black deposit of lead.
  - Zn + Pb²⁺ → Zn²⁺ + Pb
  - Zinc is more reactive than lead.
- The reactivity series can be written as a list of ionic equations:
  - Zn → Zn²⁺ + 2e
  - Fe → Fe²⁺ + 2e
  - Pb → Pb²⁺ + 2e
  - Cu → Cu²⁺ + 2e
  - Ag → Ag⁺ + e
- (i) In the space at the top of the list, write an ionic equation for a metal which is more reactive than zinc.
  - [1]
- (ii) Write an ionic equation for the reaction between aqueous silver(I) nitrate and zinc.
  - ..............................................................................................................................
  - [2]
Mark Scheme:
- (a)
  - (i) Any metal above zinc
  - Mg → Mg²⁺ + 2e^– [1]
  - (ii) Zn + 2Ag⁺ → Zn²⁺ + 2Ag [2]

Solution

(a)(i) An ionic equation for a metal more reactive than zinc is: Mg → Mg²⁺ + 2e^–.

(ii) The ionic equation for the reaction between aqueous silver(I) nitrate and zinc is: Zn + 2Ag⁺ → Zn²⁺ + 2Ag.

9.5.1 Corrosion of Iron Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

9.5.2 Barrier Methods and Sacrificial Coating Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

9.6.1 Metal Extraction Basics Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

9.6.1 Iron Extraction Paper 4 IGCSE Chemistry Topic Questions

Q1: The diagram shows a blast furnace used in the extraction of iron.

[The diagram could not be included here]

(a)
- (i) Complete the chemical equation for the reduction of iron(III) oxide in the blast furnace.
  - Fe₂O₃ + 3C → ......Fe + ......CO
  - [2]
- (ii) Explain how this equation shows that iron(III) oxide is reduced.
  - .......................................................................................................................................
  - [1]
(b) One of the products of this reaction reacts with impurities in the iron to form slag.
- Use the information in the diagram to suggest how you know that molten slag is less dense than molten iron.
  - .......................................................................................................................................
  - [1]

Mark Scheme:

(a):
- (i)
  - 2 (Fe) [1]
  - 3 (CO) [1]
- (ii) Iron oxide loses oxygen / it loses oxygen [1]
(b):
- Slag floats above the iron [1]

Solution

(a)(i) The completed chemical equation for the reduction of iron(III) oxide is: Fe₂O₃ + 3C → 2Fe + 3CO.

(ii) This equation shows that iron(III) oxide is reduced because it loses oxygen.

(b) Molten slag is less dense than molten iron because the slag floats above the iron.

9.6.1 Aluminium Extraction Paper 4 IGCSE Chemistry Topic Questions

Q1: Aluminium is extracted from its ore by electrolysis.

(a) Name the ore of aluminium which consists mainly of aluminium oxide.
- ..............................................................................................................................................
- [1]
(b) State what is meant by the term electrolysis.
- ....................................................................................................................................................
- ..............................................................................................................................................
- [2]
(c) Electrolysis is carried out on aluminium oxide dissolved in molten cryolite.
- (i) Give two reasons why the electrolysis is carried out on aluminium oxide dissolved in molten cryolite instead of electrolysing molten aluminium oxide only.
  - 1. ..........................................................................................................................................
  - 2. ..........................................................................................................................................
  - [2]
- (ii) Write the ionic half-equation for the reaction occurring at the negative electrode.
  - .......................................................................................................................................
  - [2]
- (iii) The positive electrodes are made of carbon. Explain why the positive carbon electrodes are replaced regularly.
  - .............................................................................................................................................
  - .......................................................................................................................................
  - [2]

Mark Scheme:

(a): Bauxite [1]
(b):
- M1: Breakdown by (the passage of) electricity [1]
- M2: Of an ionic compound in molten or aqueous (state) [1]
(c):
- (i)
  - M1: Improves conductivity of the electrolyte / makes the electrolyte a better conductor [1]
  - M2: Lowers operating temperature [1]
- (ii)
  - M1: Al³⁺ + 3e^– → Al
  - M1: Only Al³⁺ + (3) e^– on the left [1]
  - M2: Equation fully correct [1]
- (iii)
  - M1: Anodes or carbon react(s) with oxygen [1]
  - M2: Form carbon dioxide [1]

Solution

(a) The ore of aluminium is bauxite.

(b) Electrolysis is the breakdown by the passage of electricity of an ionic compound in molten or aqueous state.

(c)(i) Electrolysis is carried out on aluminium oxide dissolved in molten cryolite because it improves conductivity of the electrolyte and lowers the operating temperature.

(ii) The ionic half-equation for the reaction at the negative electrode is: Al³⁺ + 3e^– → Al.

(iii) The positive carbon electrodes are replaced regularly because the anodes react with oxygen and form carbon dioxide.

10.1.1 Chemical Tests for Water Paper 4 IGCSE Chemistry Topic Questions

Q1:
- (a) Describe a chemical test which shows the presence of water.
- test ..............................................................................................................................
- colour change if water is present ...................................................................
- .............................................................................................................................. [3]

Mark Scheme:
- Cobalt chloride (paper) / anhydrous cobalt chloride / CoCl₂ [1]
- From blue to pink [1]
- OR Copper sulfate / anhydrous copper sulfate / CuSO₄ [1]
- From white to blue [1]

Solution

Test: Use cobalt chloride paper or anhydrous cobalt chloride (CoCl₂).
Colour change if water is present: From blue to pink.
OR
Test: Use copper sulfate or anhydrous copper sulfate (CuSO₄).
Colour change if water is present: From white to blue.

10.1.2 Treatment of Water Paper 4 IGCSE Chemistry Topic Questions

Q1:
- Describe how water is treated before it is supplied to homes and industry.
- ..............................................................................................................................
- .............................................................................................................................. [2]

Mark Scheme:
- Any two from:
- Filtration / sedimentation / sieving / screening / (pass through) gravel beds / flocculation / decantation / clarification / coagulation / flotation / settling tank / add aluminium sulfate [1]
- (Add) carbon [1]
- Chlorination / (add) chlorine / add Cl₂ [1]
- Fluoridation / add fluoride [1]
- Ozone dosing [1]
- Desalination [1]
- Aeration [1]
- Distillation [1]

Solution

Water is treated by filtration, sedimentation, or screening to remove large particles, and chlorination is used to kill bacteria.

Or, water is treated by adding aluminium sulfate to coagulate impurities, followed by chlorination to disinfect the water.

Or, water undergoes aeration or ozone dosing to remove dissolved gases and impurities, followed by distillation or desalination for purification.

Or, carbon is added to remove odors and contaminants, and the water is fluoridated to improve dental health.

10.2 Fertilisers Paper 4 IGCSE Chemistry Topic Questions

Q1:
- Ions of the element potassium, K, are present in most fertilisers.
- State the names of two other elements that are in most fertilisers.
- 1 ...........................................................................................................................
- 2 ........................................................................................................................... [2]

Mark Scheme:
- Nitrogen [1]
- Phosphorus [1]

Solution

1. Nitrogen
2. Phosphorus

Q1:
- Some soils are acidic.
- Give the names of two compounds that are used to make soils less acidic.
- 1 ...........................................................................................................................
- 2 ........................................................................................................................... [2]

Q1:
- Some soils are acidic.
- Give the names of two compounds that are used to make soils less acidic.
- 1 ...........................................................................................................................
- 2 ........................................................................................................................... [2]

Mark Scheme:
- Calcium carbonate [1]
- Calcium oxide [1]
- Calcium hydroxide [1]

Solution

1. Calcium carbonate
2. Calcium oxide

Or, calcium hydroxide can also be used to make soils less acidic.

10.3.1 Composition of Air Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

10.3.2 Air Pollutants-Sources and Effects Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

10.3.3 Environmental Issues Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

10.3.4 Photosynthesis Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

11.1.1 Homologous Series Paper 4 IGCSE Chemistry Topic Questions

Q1: Compounds in the same homologous series have the same general formula.

(i) Give two other characteristics of members of a homologous series.
.............................................................................................................................................. [2]

Mark Scheme:

Any two from: [2]

(contain the) same functional group
differ from one member to the next by a –CH₂– unit
trend in physical properties
similar chemical properties

Solution

(i) Members of a homologous series have the same functional group and differ from one member to the next by a –CH₂– unit. [or] They show a trend in physical properties and have similar chemical properties.

11.1.2 Displayed and Structural Formulae Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

11.1.3 Structural Isomers Paper 4 IGCSE Chemistry Topic Questions

Q1:
- The formula C₄H₁₀ represents two different structural isomers.
- (i) What is meant by the term structural isomers?
- ..............................................................................................................................
- ..............................................................................................................................
- .............................................................................................................................. [2]

Mark Scheme:
- (Compounds/molecules with) the same molecular formula [1]
- Different structural formulae [1]

Solution

Structural isomers are compounds or molecules with the same molecular formula but different structural formulae.

11.1.4 Saturated and Unsaturated Compounds [ Hydrocarbons] Paper 4 IGCSE Chemistry Topic Questions

Q1:
- Describe a test for an unsaturated hydrocarbon.
- test ..............................................................................................................................
- observations ................................................................................................................. [2]

Mark Scheme:
- Aqueous bromine [1]
- Decolourises / goes colourless [1]

Solution

Test: Add aqueous bromine to the hydrocarbon.
Observations: The aqueous bromine decolourises or goes colourless if the hydrocarbon is unsaturated.

11.3.1 Fractional Distillation of Petroleum Paper 4 IGCSE Chemistry Topic Questions

Q1:
- Petroleum is a mixture of hydrocarbons, which can be separated into fractions.
- ● the name of the process used to separate the fractions
- ..............................................................................................................................
- ● how this process separates the different fractions.
- ..............................................................................................................................
- ..............................................................................................................................
- ..............................................................................................................................
- ..............................................................................................................................
- ..............................................................................................................................
- .............................................................................................................................. [4]

Mark Scheme:
- (Fractional) distillation [1]
- Petroleum vaporised / heated / turned into a gas [1]
- Temperature gradient in column / column hotter at bottom / colder at top [1]
- Smaller hydrocarbons go further up the column / larger hydrocarbons stay near the bottom of the column [1]
- Different boiling points of fractions / alkanes / molecules / hydrocarbons [1]
- Fractions / molecules / hydrocarbons come off at different heights in the column [1]

Solution

The process used to separate the fractions is fractional distillation.

In this process, petroleum is heated and vaporised. The vaporised hydrocarbons enter a column with a temperature gradient, where the bottom is hotter and the top is cooler.
Smaller hydrocarbons, which have lower boiling points, rise further up the column, while larger hydrocarbons with higher boiling points remain near the bottom. As the hydrocarbons cool, they condense at different heights in the column based on their boiling points, forming separate fractions.

11.3.2 Uses of Petroleum Fractions Paper 4 IGCSE Chemistry Topic Questions

Q1: Complete the table to show the name and uses of some petroleum fractions.

name of fraction	use of fraction
naphtha
kerosene
fuel oil

[3]

Mark Scheme:

naphtha: making chemicals [1]
kerosene: jet fuel [1]
fuel oil: fuel for ships / fuel for (home) heating [1]

Q1:
- Complete the table to show the name and uses of some petroleum fractions.

name of fraction	use of fraction
refinery gas	.......................................................................................................
gasoline	.......................................................................................................
...........................................	waxes and polishes

Mark Scheme:
- Refinery gas: heating / cooking [1]
- Gasoline: fuel for cars / fuel for vehicles [1]
- Waxes: lubricating (fraction) [1]

Solution

name of fraction	use of fraction
refinery gas	heating / cooking
gasoline	fuel for cars / vehicles
waxes	lubricating (fraction)

11.3.2 Alkane Reactions Paper 4 IGCSE Chemistry Topic Questions

Q1:
- Ethane is an alkane which undergoes a photochemical reaction with chlorine as shown:
C₂H₆(g) + Cl₂(g) → C₂H₅Cl(l) + HCl(g)
(a) Write the general formula of alkanes.
.............................................................................................................................. [1]
(b) State why this reaction is described as a photochemical reaction.
.............................................................................................................................. [1]
(c) In this reaction, an atom of hydrogen is replaced with a chlorine atom.
State the name of this type of organic reaction.
.............................................................................................................................. [1]
(d) In this reaction, one of the products is chloroethane.
Name the other product.
.............................................................................................................................. [1]

Mark Scheme:
- (a) C_nH_2n+2 [1]
- (b) Needs ultraviolet (light) [1]
- (c) Substitution [1]
- (d) Hydrogen chloride [1]

Solution

(a) C_nH_2n+2
(b) Needs ultraviolet (light)
(c) Substitution
(d) Hydrogen chloride

11.5.1 Alkene Reactions Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

11.6.1 Alcohols Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

11.7.1 Carboxylic Acids Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

11.8.1 Polymers Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

11.8.2 Plastics Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

11.8.3 Proteins Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

12.1-Experimental Design Basics Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

12.2-Titrations Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

12.3.1 Chromatography Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

12.4.1-Separation Techniques Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

12.5.1 -Test for Gases Paper 4 IGCSE Chemistry Topic Questions

Q1: Describe the test for sulfur dioxide. test: ______ and observations: ______ [2]

Test: (Aqueous) potassium manganate (VII) [1]
Observation: (Purple to) colourless [1]

Solution

Test: Use aqueous potassium manganate (VII).
Observation: The solution changes from purple to colourless.

12.5.2 -Identifying Ions Paper 4 IGCSE Chemistry Topic Questions

Q: Define market failure. [2]
Mark Scheme:
- Market failure is when the market mechanism / price mechanism / demand and supply (1).
- Does not lead to an efficient allocation of resources (1).

12.5.3 -Flame Tests Paper 4 IGCSE Chemistry Topic Questions

Q1: Describe how to do a flame test on a sample of a salt. [2]

Mark Scheme:

(Compound/salt) on wooden splint or (nichrome/platinum) wire [1]
Into (roaring) Bunsen flame [1]

Solution: Place the compound or salt on a wooden splint or nichrome/platinum wire. Insert it into a roaring Bunsen flame.

Q2: The names of the elements of Period 2 of the Periodic Table are shown.
lithium beryllium boron carbon nitrogen oxygen fluorine neon
Answer the following questions about these elements. Each element may be used once, more than once or not at all.
Identify the element which:
produces a red flame in a flame test.

Mark Scheme:

Lithium [1]

IGCSE chemistry Questions and Answers pdf

IGCSE Solved Past Papers

IGCSE Physics Solved Past Papers

Paper Type	Description	File
Paper 2 Multiple Choice	Extended Syllabus - Sample Copies	Paper-2-0625-Physics-May-June-2017-Solved.pdf Download
Paper 4 Structured Theory	Extended Syllabus - Sample Copies	Paper-4-May-June-2017-physics-solved-v-42.pdf.pdf Download
Paper 6 Alternative to Practical	Extended Syllabus - Sample Copies	Paper-6-October-November-2018-physics-Solved-V-62.pdf Download

IGCSE Chemistry Solved Past Papers

Paper Type	Description	File
Paper 2 Multiple Choice	Extended Syllabus - Sample Copies	0620_w18_qp_62-IGCSE-Chemistry-Solved-Past-Paper.pdf Download
Paper 4 Structured Theory	Extended Syllabus - Sample Copies	0620_w18_qp_42-IGCSE-Chemistry-Solved-Past-Paper.pdf Download
Paper 6 Alternative to Practical	Extended Syllabus - Sample Copies	0620_s18_qp_22-IGCSE-Chemistry-Solved-Past-Paper.pdf Download

IGCSE Biology Solved Past Papers

Paper Type	Description	File	View More
Paper 4 Structured Theory	Extended Syllabus - Sample Copies	0610_s19_qp_42-IGCSE-Biology-Solved-Past-Paper-Questions-And-Answers.pdf Download
Paper 6 Alternative to Practical	Extended Syllabus - Sample Copies	0610_s19_qp_62-IGCSE-Biology-Solved-Past-Paper-Questions-And-Answers.pdf Download

Smart Edu Hub

Cambridge Checkpoints / IGCSE / AS and A levels

IGCSE SOLVED PAPER LINKS

IGCSE Chemistry Past Papers & Solved Topic Questions | Free Resources

Question:

Mark Scheme:

Solution:

IGCSE chemistry Questions and Answers pdf

IGCSE Physics Solved Past Papers

IGCSE Chemistry Solved Past Papers