Question 1 (B1.1)
Which characteristic of living organisms is defined as the chemical reactions that break down nutrient molecules and release energy for metabolism?
A. excretion
B. nutrition
C. respiration
D. reproduction
▶️Answer/Explanation
Answer: C
Explanation: Respiration is the process by which cells break down nutrient molecules to release energy for metabolism. Excretion refers to the removal of waste products, nutrition involves taking in materials for energy and growth, and reproduction is the process of producing offspring.
Question 2 (B3.1)
What is the net movement of molecules during diffusion?
A. from a higher concentration to a lower concentration down a concentration gradient
B. from a higher concentration to a lower concentration up a concentration gradient
C. from a lower concentration to a higher concentration down a concentration gradient
D. from a lower concentration to a higher concentration up a concentration gradient
▶️Answer/Explanation
Answer: A
Explanation: Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration, down the concentration gradient. This process occurs due to the random motion of particles and does not require energy input.
Question 3 (B4.1)
A food contains reducing sugar, but no starch. What colours will be obtained if samples of the food are tested with Benedict’s solution and with iodine solution?
| Benedict’s test | iodine test | |
|---|---|---|
| A | blue | blue-black |
| B | blue | brown |
| C | red-orange | blue-black |
| D | red-orange | brown |
▶️Answer/Explanation
Answer: D
Explanation: Benedict’s solution turns from blue to red-orange in the presence of reducing sugars. Iodine solution remains brown when no starch is present (it only turns blue-black if starch is present). Since the food contains reducing sugar but no starch, the correct combination is red-orange with Benedict’s and brown with iodine.
Question 4 (B5.1)
Which statement correctly describes enzyme activity as the temperature increases up to an optimum temperature?
A. The enzyme has less frequent effective collisions with the product.
B. The enzyme has less frequent effective collisions with the substrate.
C. The enzyme has more frequent effective collisions with the product.
D. The enzyme has more frequent effective collisions with the substrate.
▶️Answer/Explanation
Answer: D
Explanation: As temperature increases up to the optimum, enzyme and substrate molecules move faster, leading to more frequent effective collisions between enzyme and substrate. This increases the rate of reaction until the optimum temperature is reached.
Question 5 (B6.1)
A plant which is deficient in nitrates and magnesium has yellow leaves and poor growth. What is the importance of these two ions in plant growth?
| importance of nitrate ions | importance of magnesium ions | |
|---|---|---|
| A | making amino acids | production of chlorophyll |
| B | making amino acids | production of roots |
| C | making fatty acids | production of chlorophyll |
| D | making fatty acids | production of roots |
▶️Answer/Explanation
Answer: A
Explanation: Nitrate ions are needed for making amino acids, which are building blocks for proteins. Magnesium ions are essential for chlorophyll production, and their deficiency causes chlorosis (yellowing of leaves). Poor growth results from protein and chlorophyll deficiency.
Question 6 (B7.1)
Why is calcium needed in the diet?
A. to make carbohydrates
B. to make teeth
C. to make enzymes
D. to make protein
▶️Answer/Explanation
Answer: B
Explanation: Calcium is a mineral needed for strong bones and teeth. It is a component of hydroxyapatite in teeth and bones. While calcium ions play roles in enzyme activation and other processes, its primary dietary importance is for skeletal structure.
Question 7 (B9.3)
The diagram shows the double circulatory system to the lungs and the body.
In which two blood vessels is the pressure the highest?
A. V and W
B. W and Y
C. X and V
D. Y and X
▶️Answer/Explanation
Answer: B
Explanation: Blood pressure is highest in the arteries leaving the heart (W = aorta and Y = pulmonary artery) as these vessels receive blood directly from the ventricles which contract forcefully. Pressure decreases as blood moves through the circulatory system.
Question 8 (B11.1)
Cigarette smoke paralyses the cilia in the gas exchange system. What is the direct result of this?
A. Mucus accumulates in the airways.
B. Oxygen cannot diffuse into the blood.
C. The blood cannot carry oxygen efficiently.
D. The smoker develops lung cancer.
▶️Answer/Explanation
Answer: A
Explanation: Cilia normally move mucus containing trapped particles upward and out of the airways. When cilia are paralyzed, mucus accumulates, leading to ‘smoker’s cough’ as the body tries to clear the airways. The other options describe potential long-term effects but not the direct result of cilia paralysis.
Question 9 (B13.3)
What happens when the body temperature falls below normal?
A. Arterioles supplying the skin constrict.
B. Arterioles supplying the skin dilate.
C. Capillaries move towards the skin surface.
D. Capillaries move away from the skin surface.
▶️Answer/Explanation
Answer: A
Explanation: When body temperature drops, arterioles supplying skin capillaries constrict (vasoconstriction) to reduce blood flow near the skin surface, minimizing heat loss. This is part of the body’s thermoregulatory response to maintain core temperature.
Question 10 (B15.3)
An experiment using germinating seeds is set up as shown, and left at room temperature for 12 hours.
The pump is then switched on and air is drawn through the apparatus for 2 minutes.
Which row identifies solutions P and Q and the results obtained?
▶️Answer/Explanation
Answer: C
Question 11 (B15.4)
Chimpanzee gametes contain one more chromosome than human gametes.
What is the chromosome number in a chimpanzee diploid cell?
A. 23
B. 24
C. 46
D. 48
▶️Answer/Explanation
Answer: D
Explanation: Human gametes (sperm/egg) contain 23 chromosomes, so human diploid cells have 46 chromosomes. Since chimpanzee gametes contain one more chromosome (24), their diploid cells would have 48 chromosomes (2 × 24).
Question 12 (B18.2)
The flow chart shows part of a food chain:
grass → rabbit → fox
What describes the rabbit?
A. consumer and carnivore
B. consumer and herbivore
C. producer and carnivore
D. producer and herbivore
▶️Answer/Explanation
Answer: B
Explanation: The rabbit eats grass (producer), making it a consumer. Since it eats plants, it’s specifically a herbivore. It cannot be a producer as it doesn’t produce its own food through photosynthesis.
Question 13 (B19.1)
Which line shows how the oxygen concentration of the water changes after excess fertiliser has entered a stream?
▶️Answer/Explanation
Answer: B
Explanation: Excess fertilizer causes algal blooms which initially decrease oxygen as algae respire at night. When algae die, decomposers further deplete oxygen. Eventually, as the ecosystem recovers, oxygen levels increase again.
Question 14 (C2.2)
Which statement about atoms and molecules is correct?
A. All molecules are gases at room temperature and pressure.
B. An atom is the smallest part of an element.
C. Atoms of the same element all have the same mass.
D. Molecules always contain atoms of more than one element.
▶️Answer/Explanation
Answer: B
Explanation: An atom is indeed the smallest unit of an element that retains its properties. Option A is incorrect as molecules can be solids/liquids. C is wrong due to isotopes. D is incorrect as elements like O₂ are molecules.
Question 15 (C2.4)
Which compound is formed when one metal atom transfers two electrons to one non-metal atom?
A. calcium chloride
B. calcium oxide
C. sodium chloride
D. sodium oxide
▶️Answer/Explanation
Answer: B
Explanation: Calcium (Group 2) loses 2 electrons to form Ca²⁺, while oxygen (Group 6) gains 2 electrons to form O²⁻, creating calcium oxide (CaO). The 1:1 ratio satisfies the electron transfer.
Question 16 (C3.3)
What is the volume of 0.35 mol of hydrogen gas at room temperature and pressure?
A. 2.1 dm³
B. 4.2 dm³
C. 8.4 dm³
D. 16.8 dm³
▶️Answer/Explanation
Answer: C
Explanation: At r.t.p., 1 mole of gas occupies 24 dm³. Therefore, 0.35 mol occupies 0.35 × 24 = 8.4 dm³.
Question 17 (C4.1)
The diagram shows the electrolysis of lead(II) bromide using inert electrodes.
Which statement about this experiment is correct?
A. Electrode X is positively charged.
B. The coloured fumes are produced at the negative electrode.
C. The electrolyte is lead(II) bromide.
D. The grey solid is lead(II) bromide.
▶️Answer/Explanation
Answer: C
Explanation: Lead(II) bromide is indeed the electrolyte being decomposed. The grey solid is lead metal (formed at cathode), and brown bromine fumes form at the anode (positive electrode).
Question 18 (C6.2)
An acid reacts with solid lumps of calcium carbonate to produce a salt, water and carbon dioxide.
Which changes lead to a greater frequency of successful collisions between reacting particles?
1. Increase the temperature of the acid.
2. Use powdered lumps of calcium carbonate.
3. Use a different acid with a higher pH.
A. 1 and 2 only
B. 1 and 3 only
C. 2 and 3 only
D. 1, 2 and 3
▶️Answer/Explanation
Answer: A
Explanation: Increasing temperature (1) gives particles more kinetic energy. Powdering (2) increases surface area. Both increase collision frequency. A higher pH acid (3) would be less concentrated, reducing collisions.
Question 19 (C4.1)
The ionic equation for the formation of chromium(III) ions is shown.
Cr → Cr3+ + 3e–
Which statement about chromium atoms is correct?
A. They are oxidised by gaining electrons.
B. They are oxidised by losing electrons.
C. They are reduced by gaining electrons.
D. They are reduced by losing electrons.
▶️Answer/Explanation
Answer: B
Explanation: In the given equation, chromium atoms lose electrons (3e–) to form Cr3+ ions. Loss of electrons is oxidation, so chromium atoms are being oxidized.
Question 20 (C7.2)
X is an oxide. When solid X is added to dilute hydrochloric acid, the pH of the solution increases. When solid X is added to aqueous sodium hydroxide, the pH of the solution decreases.
Which type of oxide is X?
A. acidic
B. amphoteric
C. basic
D. neutral
▶️Answer/Explanation
Answer: B
Explanation: Amphoteric oxides react with both acids and bases. The pH increase with HCl suggests X is neutralizing the acid (basic behavior), while the pH decrease with NaOH suggests X is neutralizing the base (acidic behavior), characteristic of amphoteric oxides like Al2O3 or ZnO.
Question 21 (C12.4)
Copper sulfate is made by adding an excess of copper carbonate to dilute sulfuric acid and stirring. The excess solid is removed. Most of the water is then removed. The solution is left for solid copper sulfate to form.
In which order is apparatus used?
A. Bunsen burner, tripod and flask → filter funnel → crystallising dish
B. Bunsen burner, tripod and flask → crystallising dish → filter funnel
C. filter funnel → crystallising dish → Bunsen burner, tripod and flask
D. filter funnel → Bunsen burner, tripod and flask → crystallising dish
▶️Answer/Explanation
Answer: D
Explanation: First filtration (filter funnel) removes excess copper carbonate, then heating (Bunsen burner setup) removes most water, and finally crystallization (crystallising dish) allows pure copper sulfate crystals to form.
Question 22 (C9.3)
Which diagram represents an alloy?
▶️Answer/Explanation
Answer: A
Explanation: An alloy is a mixture of a metal with other elements where the different sized atoms disrupt the regular lattice structure of the pure metal, making it harder and stronger.
Question 23 (C9.2)
Which statement is not a reason why aluminium is used in aircraft manufacture?
A. It forms low density alloys.
B. It is malleable.
C. It is more reactive than iron.
D. It is resistant to corrosion.
▶️Answer/Explanation
Answer: C
Explanation: While A, B, and D are advantages for aircraft use, reactivity (C) is not a desirable property for structural materials. Aluminium’s usefulness comes despite its reactivity, due to its protective oxide layer.
Question 24 (C8.3)
Chlorine gas is bubbled through two separate solutions.
What is observed in the two tubes?
| potassium bromide tube | potassium iodide tube | |
|---|---|---|
| A | colourless solution turns orange | colourless solution turns brown |
| B | colourless solution turns orange | solution remains colourless |
| C | orange solution turns colourless | brown solution turns colourless |
| D | orange solution turns colourless | solution remains brown |
▶️Answer/Explanation
Answer: A
Explanation: Chlorine is more reactive than both bromine and iodine, so it will displace them from their compounds. When chlorine gas is bubbled through:
1. Potassium bromide solution: Chlorine displaces bromine, forming orange bromine solution (2KBr + Cl₂ → 2KCl + Br₂)
2. Potassium iodide solution: Chlorine displaces iodine, forming brown iodine solution (2KI + Cl₂ → 2KCl + I₂)
This demonstrates the reactivity trend in Group VII (halogens) where higher elements displace lower ones from their compounds.
Question 25 (C10.2)
Limestone is converted to lime in process 1. Limestone is used to treat industrial waste in process 2.
What are processes 1 and 2?
| process 1 | process 2 | |
|---|---|---|
| A | decomposition | dissolving |
| B | decomposition | neutralisation |
| C | oxidation | dissolving |
| D | oxidation | neutralisation |
▶️Answer/Explanation
Answer: B
Explanation: Process 1 is the thermal decomposition of limestone (calcium carbonate) to produce lime (calcium oxide): CaCO₃ → CaO + CO₂
Process 2 is neutralization where limestone is used to treat acidic industrial waste by neutralizing the acid: CaCO₃ + 2H⁺ → Ca²⁺ + CO₂ + H₂O
This shows two important industrial applications of limestone – in manufacturing and pollution control.
Question 26 (C11.1)
The structures of three organic compounds are shown.
Which statement about these three compounds is correct?
A. They are alcohols.
B. They are alkenes.
C. They are saturated.
D. They do not burn.
▶️Answer/Explanation
Answer: C
Explanation: All three compounds shown are saturated hydrocarbons (alkanes) as they contain only single bonds between carbon atoms.
– They are not alcohols (no -OH group)
– They are not alkenes (no C=C double bonds)
– They do burn (alkanes are combustible)
The key feature is that they are saturated, meaning they contain the maximum possible number of hydrogen atoms with no double or triple bonds.
Question 27 (C11.7)
Which row matches the name of a polymer to the formula of the monomer from which it is made?
| polymer | monomer | |
|---|---|---|
| A | poly(ethene) | C₂H₂ |
| B | poly(ethene) | C₂H₆ |
| C | poly(propene) | C₂H₄ |
| D | poly(propene) | C₃H₆ |
▶️Answer/Explanation
Answer: D
Explanation: The correct match is:
– Poly(propene) is made from propene (C₃H₆) monomers
Other options are incorrect because:
A: C₂H₂ is ethyne (used to make poly(ethyne), not poly(ethene)
B: C₂H₆ is ethane (a saturated hydrocarbon that doesn’t polymerize)
C: C₂H₄ is ethene (used to make poly(ethene), not poly(propene)
This question tests understanding of addition polymerization where unsaturated monomers (with C=C bonds) join together.
Question 28 (P1.2)
The diagrams show two distance-time graphs and two speed-time graphs for objects travelling in a straight line.
Which graph represents an object with a constant, positive acceleration of 5.0 m/s²?
▶️Answer/Explanation
Answer: C
Explanation: A constant positive acceleration is represented by a straight line with positive gradient on a speed-time graph (Graph C).
– Graph A: Distance-time with constant speed (zero acceleration)
– Graph B: Distance-time with changing speed (acceleration not constant)
– Graph D: Speed-time with zero gradient (constant speed, zero acceleration)
The acceleration can be calculated from the gradient of the speed-time graph: a = Δv/Δt. For Graph C, if we take two points, say (0,0) and (4,20), the acceleration is (20-0)/(4-0) = 5 m/s².
Question 29 (P1.7)
A force F acting on an area A exerts a pressure P. What pressure is exerted by a force of 2F acting on an area 0.50A?
A. 0.50P
B. P
C. 2.0P
D. 4.0P
▶️Answer/Explanation
Answer: D
Explanation: Pressure is calculated as P = F/A
Original situation: P = F/A
New situation: P’ = (2F)/(0.50A) = 4(F/A) = 4P
When the force doubles and the area halves, the pressure increases by a factor of 4. This demonstrates the inverse relationship between pressure and area when force changes.
Question 30 (P1.6.1)
An object is moving along a straight path with 200 J of kinetic energy. A resultant force acts on the object, in the direction it is moving, for a distance of 20 m. The kinetic energy of the object increases to 1000 J.
What is the magnitude of the force?
A. 10 N
B. 40 N
C. 50 N
D. 60 N
▶️Answer/Explanation
Answer: B
Explanation: The work done by the force equals the change in kinetic energy (work-energy theorem):
Work done = ΔKE = 1000 J – 200 J = 800 J
Work done = Force × distance
800 J = F × 20 m
F = 800/20 = 40 N
This calculation shows how energy considerations can be used to determine forces when distances are known.
Question 31 (P1.6.1)
An object of mass m moving with speed v has kinetic energy E. A second object, also of mass m, moves with speed v/2. What is the kinetic energy of the second object?
A. E/4
B. E/2
C. E
D. 2E
▶️Answer/Explanation
Answer: A
Explanation: Kinetic energy is given by E = ½mv²
For the first object: E = ½mv²
For the second object: E’ = ½m(v/2)² = ½m(v²/4) = (½mv²)/4 = E/4
Since kinetic energy depends on the square of velocity, halving the speed reduces the energy to one quarter of its original value (when mass is constant).
Question 32 (P1.6.3)
Which statement describes the production of electricity from a renewable energy source?
A. Coal is burnt to release energy to make steam that turns a generator.
B. Moving air passes over blades that rotate and turn a generator.
C. Nuclear fission releases energy to make steam that turns a generator.
D. Oil is burnt to release energy to make steam that turns a generator.
▶️Answer/Explanation
Answer: B
Explanation: Option B describes wind power, which is renewable as wind is continually replenished by natural processes.
The other options describe non-renewable sources:
A & D: Fossil fuels (coal and oil) are finite resources
C: Nuclear fuel (uranium) is non-renewable
Renewable energy sources include wind, solar, hydroelectric, geothermal, and tidal power, which are naturally replenished on a human timescale.
Question 33 (P2.2.2)
A liquid-in-glass thermometer contains mercury. The thermometer is moved from cold water into hot water. What happens to the mercury?
A. It contracts.
B. It expands.
C. It freezes.
D. It melts.
▶️Answer/Explanation
Answer: B
Explanation: Mercury, like most liquids, expands when heated. When the thermometer is moved from cold to hot water:
1. The mercury absorbs heat energy from the hot water
2. The mercury atoms gain kinetic energy and move further apart
3. This increased volume causes the mercury to rise in the thermometer’s narrow tube
The expansion is linear with temperature, allowing accurate temperature measurement. Freezing (C) and melting (D) would only occur at extreme temperatures (-38.8°C and 356.7°C respectively for mercury).
Question 34 (P2.3)
A hot water tank is fitted with two identical heaters P and Q. Heater P is fitted above heater Q as shown. The tank is full of cold water.
When only heater Q is switched on, it takes a long time to heat the tank of water to 60°C.
What happens to the cold water when only heater P is switched on?
A. All the water reaches 60°C in less time.
B. All the water reaches 60°C in the same time.
C. The water below heater P reaches 60°C in less time.
D. The water above heater P reaches 60°C in less time.
▶️Answer/Explanation
Answer: D
Explanation: When heater P (upper heater) is used:
1. The water near P heats up first due to direct contact
2. Hot water is less dense and stays at the top (no convection current forms)
3. Heat transfer to lower water occurs slowly by conduction
Thus only the water above heater P heats up quickly, while the lower water remains cold longer. This demonstrates how convection currents are essential for efficient heating of fluids – with heater Q at the bottom, convection currents form, circulating hot water throughout the tank.
Question 35 (P3.2.3)
Which ray diagram represents the formation of a virtual image I of an object O?
▶️Answer/Explanation
Answer: A
Explanation: A virtual image is formed when:
1. The object is inside the focal length of a converging lens
2. The diverging rays appear to come from a point on the same side as the object
3. The image is upright and magnified
Diagram A shows this configuration correctly. The other diagrams show:
B: Real image (object outside focal length)
C: Incorrect ray tracing
D: No image formation
Virtual images cannot be projected on a screen but can be seen by looking through the lens.
Question 36 (P3.4)
Which statement about the transmission of sound is correct?
A. Sound does not need a medium
B. Sound travels faster in gases than in solids
C. The particles of the transmission medium vibrate parallel to the direction in which the sound travels
D. The regions in the transmission medium where the particles are closest together are called rarefactions
▶️Answer/Explanation
Answer: C
Explanation: Sound is a longitudinal wave where particles vibrate parallel to the direction of wave propagation. Option A is incorrect because sound requires a medium. Option B is incorrect as sound travels fastest in solids. Option D is wrong because regions where particles are closest are compressions, not rarefactions.
Question 37 (P4.2.4)
The diagram shows a wire with resistance R.
Both the length and the diameter of the wire are now doubled. What is the new resistance of the wire after both of these changes?
A. R/2
B. R
C. 2R
D. 4R
▶️Answer/Explanation
Answer: A
Explanation: Resistance is directly proportional to length and inversely proportional to cross-sectional area (which depends on diameter squared). Doubling length increases resistance by 2×, while doubling diameter decreases resistance by 4× (since area increases by 4×). The net effect is (2×)/(4×) = 1/2 the original resistance.
Question 38 (P4.5.2)
Which graph shows the voltage output of an alternating current (a.c.) generator?
▶️Answer/Explanation
Answer: D
Explanation: An AC generator produces a sinusoidal (sine wave) output voltage that alternates smoothly between positive and negative values. This represents the continuous rotation of the coil in a magnetic field, with the voltage varying as the sine of the angle between the coil and field.
Question 39 (P4.4)
A fuse is a safety device for use in an electrical circuit. The current in the circuit becomes greater than the rated value for the fuse.
What happens?
A. The current decreases to zero
B. The current decreases to the rated value for the fuse
C. The thickness of the insulation around the wires increases
D. The current is sent to the outer case of the appliance
▶️Answer/Explanation
Answer: A
Explanation: When current exceeds the fuse’s rating, the fuse wire melts due to overheating, breaking the circuit and reducing current to zero. This protects the circuit from damage due to excessive current. Fuses don’t regulate current (B) or affect insulation (C), and don’t redirect current (D).
Question 40 (P5.1)
The diagrams represent the nuclei of four different atoms V, W, X and Y.
Which two diagrams represent isotopes of the same element?
A. V and Y
B. W and X
C. X and Y
D. Y and W
▶️Answer/Explanation
Answer: C
Explanation: Isotopes are atoms of the same element (same number of protons) with different numbers of neutrons. From the diagrams, X and Y have the same number of protons but different numbers of neutrons, making them isotopes. The other pairs either have different proton numbers or aren’t paired correctly.