Form Four Chemistry Mid-term 1 papers
The 2026 paper is free to try here
Mid-term 1 is the first assessment of the year and is set in March. Use these papers to test yourself under exam conditions, then check your work with the marking scheme.
2026 Form Four Chemistry Mid-term 1 exam (March)
Time: 3 hours · Section A: 16 marks · Section B: 54 marks · Section C: 30 marks
Instructions from the paper:
• This paper consists of sections A, B and C with a total of eleven (11) questions.
• Answer all questions in Sections A and B, and two questions from Section C.
• Section A carries 16 marks, Section B 54 marks and Section C 30 marks.
How to use this page: choose an option for each multiple-choice question and click “Check Answer”. A correct answer plays a short sound and shows an explanation; a wrong answer shows the right option and why. For the matching item and written questions, answer on paper first, then click “View Answer”.
SECTION A (16 marks): Question 1 — Multiple Choice (10 marks)
(i) What is the IUPAC name for H2SO4?
(ii) Consider the following fuels: 1. Coal 2. Firewood 3. Petrol 4. Charcoal. Which fuels originate from fossils?
(iii) Glucose dissolves in water to form a uniform mixture. Which statement is correct?
(iv) The reason why white anhydrous copper(II) sulphate turns blue when exposed to the atmosphere is that it:
(v) Which scientific procedure is used to accept or reject a hypothesis?
(vi) Why should sodium hydroxide pellets be stored in a closed container?
(vii) The oxidation number of phosphorus in the radical PO43− is:
(viii) The magnesium salt responsible for permanent hardness of water is:
(ix) Organic compounds with the general formula RCOOH are known as:
(x) Which of the following are the components needed to start a fire?
SECTION A continued: Question 2 — Matching Item (6 marks)
Match the materials in List A with the correct method of separation in List B. Write the letter of the correct answer beside each item. (6 marks)
| # | List A | Your answer |
|---|---|---|
| i | Alcohol and water | |
| ii | Cooking oil and water | |
| iii | Oil from seeds | |
| iv | Sulphur and iron filings | |
| v | Table salt crystals and ammonium chloride crystals | |
| vi | Beans and water |
List B
- A. Layer separation
- B. Solvent extraction
- C. Filtration
- D. Magnetization
- E. Chromatography
- F. Sublimation
- G. Fractional distillation
Correct matches (1 mark each): i-G, ii-A, iii-B, iv-D, v-F, vi-C
- i. Alcohol and water → Fractional distillation (different boiling points)
- ii. Cooking oil and water → Layer separation (immiscible liquids)
- iii. Oil from seeds → Solvent extraction
- iv. Sulphur and iron filings → Magnetization (iron is magnetic)
- v. Table salt and ammonium chloride → Sublimation (NH₄Cl sublimes)
- vi. Beans and water → Filtration
SECTION B (54 marks): Questions 3–8
3. (a) A student prepared gas A by reacting a moderately reactive metal with dilute acid.
(i) Name gas A.
(ii) State the chemical test that distinguishes this gas from other gases.
(iii) With two reasons, state the correct method of collecting the gas.
(iv) Write the balanced chemical equation for the reaction (using zinc and hydrochloric acid as an example).
(b) Suggest four ways that can be used to make the reaction faster.
Suggested answer and marking guide
(a)
- (i) Hydrogen gas (H2) (2 marks)
- (ii) Burns with a pop sound (2 marks)
- (iii) Collected by downward displacement of water (or over water) because: (a) it is only slightly soluble in water; (b) it is less dense than air (2 marks)
- (iv) Zn + 2HCl → ZnCl2 + H2 (1 mark)
(b) Any four: use a catalyst (e.g. copper or MnO2); increase temperature; increase concentration of acid; use powdered metal (larger surface area); stir the mixture (1 mark each, max 4).
4. (a) A Form One student has a balloon filled with a certain gas. If the balloon is put in a freezer overnight, what will happen to it? Explain.
(b) How does temperature affect the state of matter?
Suggested answer and marking guide
(a) The balloon will shrink / become smaller (2 marks). Decrease in temperature causes the gas molecules to lose kinetic energy, move more slowly and occupy a smaller volume (2 marks).
(b) Temperature affects the movement and energy of particles. Increasing temperature increases particle movement and can cause melting and evaporation; decreasing temperature reduces particle movement and can cause condensation and freezing (5 marks).
5. 20 g of copper(II) oxide reacted with ammonia gas at STP according to the equation:
3CuO(s) + 2NH3(g) → 3Cu(s) + N2(g) + 3H2O(g)
Calculate:
(a) the number of moles of copper(II) oxide used;
(b) the number of moles of ammonia gas used;
(c) the volume of ammonia gas used.
Suggested answer and marking guide
- (a) Molar mass of CuO = 63.5 + 16 = 79.5 g mol−1. Moles of CuO = 20 / 79.5 = 0.2516 ≈ 0.25 mol (3 marks)
- (b) From the equation, 3 mol CuO require 2 mol NH3, so 0.25 mol CuO require (2/3) × 0.25 = 0.167 mol NH3 (3 marks)
- (c) At STP, 1 mol gas occupies 22.4 dm3. Volume of NH3 = 0.167 × 22.4 ≈ 3.74 dm3 (3 marks)
6. (a) (i) List three physical properties of an acid and three of a base.
(ii) Differentiate between the strength of an acid and the concentration of an acid.
(b) Mr Mlonga was suffering from heartburn and took wood-ash solution; he got relief.
(i) Name the process that took place in his stomach.
(ii) Give four applications of this process in everyday life.
Suggested answer and marking guide
(a)(i) Acids: sour taste, turn blue litmus red, corrosive (any three). Bases: bitter taste, turn red litmus blue, slippery/soapy feel, most are insoluble in water (any three).
(a)(ii) Strength measures the degree of ionisation (strong acids ionise completely). Concentration measures the amount of acid dissolved in a given volume of solvent (1 mark each).
(b)(i) Neutralisation (1 mark).
(b)(ii) Any four: treating insect stings/bites; relieving indigestion; soil treatment (liming); treating factory wastes; preventing acid rain effects; manufacture of fertilisers (0.5–1 mark each).
7. (a) Give the difference between the following pairs of terms as applied in electrolysis:
(i) Electrolytes and non-electrolytes
(ii) Cathode and anode
(iii) Strong electrolytes and weak electrolytes
(iv) Electrolytic cell and a battery
(b) “A dilute electrolyte is not necessarily weak and a concentrated electrolyte is not necessarily strong.” Explain.
Suggested answer and marking guide
- (i) Electrolyte: dissociates into free ions in solution or molten state and conducts electricity. Non-electrolyte: does not produce ions and does not conduct (e.g. sugar, oil) (2 marks).
- (ii) Cathode: negative electrode where reduction occurs / current leaves the electrolyte. Anode: positive electrode where oxidation occurs (2 marks).
- (iii) Strong electrolytes dissociate completely; weak electrolytes dissociate only partially (1 mark).
- (iv) Electrolytic cell: the apparatus in which electrolysis is carried out. Battery: the source of direct current (2 marks).
(b) Dilute / concentrated refer to the amount of solute present; strong / weak refer to the degree of ionisation. A dilute solution of a strong electrolyte (e.g. NaCl) still ionises completely; a concentrated solution of a weak electrolyte may still be only partially ionised (1–2 marks).
8. (a) Explain the following concepts:
(i) Collision theory
(ii) Effective collision
(iii) Activation energy
(b) The Haber process is an example of chemical equilibrium: N2 + 3H2 ⇌ 2NH3. Describe the effects of temperature and pressure on this reaction.
Suggested answer and marking guide
- (i) Collision theory: reactant particles must collide with sufficient energy and correct orientation for a reaction to occur (2 marks).
- (ii) Effective collision: a collision that results in product formation (has activation energy and correct orientation) (2 marks).
- (iii) Activation energy: the minimum energy required for reactant molecules to react (2 marks).
(b) The forward reaction is exothermic. Lower temperature favours a higher yield of ammonia but slows the rate; higher temperature lowers the yield. Higher pressure increases the yield of ammonia (fewer moles on the product side) (3 marks).
SECTION C (30 marks): Answer any two questions
9. Describe the extraction of iron from its ore and write the chemical equations for the reactions involved in each stage.
Suggested answer and marking guide
Iron is extracted from haematite (Fe2O3) in a blast furnace using coke and limestone.
- Loading: Iron ore, coke and limestone are charged at the top; hot air is blasted from the bottom.
- Combustion of coke: C + O2 → CO2 (heat generated).
- Formation of CO: CO2 + C → 2CO.
- Reduction of ore: Fe2O3 + 3CO → 2Fe + 3CO2 (molten iron).
- Slag formation: CaCO3 → CaO + CO2; CaO + SiO2 → CaSiO3 (slag floats and is removed).
(About 1.5 marks per stage / equation; total ~9–10 marks for a complete description.)
10. From the structural formulae HC≡CCH2CH3, CH3(CH2)2CH3 and H2C=CHCH2CH3:
(a) To which family does each compound belong?
(b) Identify the compound(s) that will decolorise bromine water (i) in the dark only and (ii) in the presence of UV light only.
Suggested answer and marking guide
(a)
- HC≡CCH2CH3 (but-1-yne / propyne family) — alkyne (triple bond) (2 marks)
- CH3(CH2)2CH3 (butane) — alkane (single bonds only) (2 marks)
- H2C=CHCH2CH3 (but-1-ene) — alkene (double bond) (2 marks)
(b)
- (i) Dark only: the alkene and alkyne (unsaturated) decolorise bromine water immediately by addition (1.5 marks)
- (ii) UV light only: the alkane (butane) reacts slowly by substitution under UV light (1.5 marks)
11. Global warming is one of the major problems in the world. Explain any five effects of global warming.
Suggested answer and marking guide
Introduction (2 marks): brief definition of global warming as the long-term rise in Earth’s average temperature due mainly to greenhouse gases.
Any five effects (2 marks each = 10 marks), for example:
- Rising global temperatures
- Melting ice caps and rising sea levels
- More frequent extreme weather events (droughts, floods, storms)
- Disruption of ecosystems and loss of biodiversity
- Threats to agriculture and food security
- Health problems (heat stress, spread of disease)
- Ocean acidification
- Economic costs and disruption of water supplies
Conclusion (3 marks): summary and possible mitigation measures.
Total ≈ 15 marks for a well-structured essay.
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Which Form Four Chemistry Mid-term 1 exams are available?
The March Mid-term 1 papers for 2024, 2025 and 2026. The 2026 paper is open on this page with interactive answers, and the other papers are on the Click Online Academy app.
How do I use the interactive paper?
Answer the multiple-choice questions and click Check Answer to see whether you are right and why. For the matching item and the written questions, answer on paper first, then click View Answer to see the suggested answer and marking guide.
When is Mid-term 1 held?
Mid-term 1 is the first assessment of the year and is set in March. Mid-term 2 follows in August.