Question 1 (B1.1)
Which characteristic of living organisms is correctly matched to the description?
| characteristic | description | |
|---|---|---|
| A | excretion | the removal from organisms of the waste products of metabolism |
| B | nutrition | the chemical reactions in cells that break down nutrient molecules and release energy for metabolism |
| C | respiration | the taking in of materials for energy, growth and development |
| D | sensitivity | the action by an organism or part of an organism causing a change of position or place |
▶️Answer/Explanation
Answer: A
Explanation: Option A is correct because excretion is indeed the removal of metabolic waste products. Option B describes respiration, not nutrition. Option C describes nutrition, not respiration. Option D describes movement, not sensitivity.
Question 2 (B3.2)
The diagram shows a cell starting to plasmolyse.
In which direction is osmosis occurring?
A X to Y
B Y to X
C Y to Z
D Z to Y
▶️Answer/Explanation
Answer: D
Explanation: During plasmolysis, water moves out of the cell (from Z to Y in the diagram) from a region of higher water potential to lower water potential through the partially permeable membrane.
Question 3 (B4.1)
Which chemical element is found in proteins, but not in carbohydrates or fats?
A carbon
B hydrogen
C oxygen
D nitrogen
▶️Answer/Explanation
Answer: D
Explanation: Nitrogen is present in proteins (in amino groups) but absent in carbohydrates and fats, which only contain carbon, hydrogen and oxygen.
Question 4 (B5.1)
Which statement about enzyme action is correct?
A The active site of the enzyme is complementary to the product and a substrate is formed.
B The active site of the substrate is complementary to the enzyme and a product is formed.
C The active site of the product is complementary to the enzyme and a substrate is formed.
D The active site of the enzyme is complementary to the substrate and a product is formed.
▶️Answer/Explanation
Answer: D
Explanation: Enzymes have active sites with complementary shapes to their specific substrates. When the substrate binds, products are formed through the enzyme-catalyzed reaction.
Question 5 (B6.1)
Which two arrows represent photosynthesis?
A 1 and 3
B 1 and 4
C 2 and 3
D 2 and 4
▶️Answer/Explanation
Answer: B
Explanation: Photosynthesis involves plants taking in carbon dioxide (arrow 1) and releasing oxygen (arrow 4) as byproducts of the process that converts light energy to chemical energy.
Question 6 (B7.1)
What is deficient in the diet when growing bones become soft and deformed?
A iron
B protein
C vitamin C
D vitamin D
▶️Answer/Explanation
Answer: D
Explanation: Vitamin D deficiency causes rickets, characterized by soft, deformed bones. Vitamin D is essential for calcium absorption and proper bone mineralization.
Question 7 (B9.2)
The diagram shows a section through the heart.
When ventricles contract, which valves open and which valves close?
| open | close | |
|---|---|---|
| A | 1 and 3 | 2 and 4 |
| B | 1 and 4 | 2 and 3 |
| C | 2 and 3 | 1 and 4 |
| D | 2 and 4 | 1 and 3 |
▶️Answer/Explanation
Answer: C
Explanation: During ventricular contraction (systole), the semilunar valves (2 and 3) open to allow blood flow to arteries, while the atrioventricular valves (1 and 4) close to prevent backflow.
Question 8 (B6.1)
Hydrogencarbonate indicator changes color with different concentrations of carbon dioxide.
A pond contains both plants and animals. Samples of pond water are taken during a sunny day and again during the night. Each sample is tested with hydrogencarbonate indicator.
What would be the results of these tests?
| day sample | night sample | |
|---|---|---|
| A | purple | yellow |
| B | red | purple |
| C | red | red |
| D | yellow | purple |
▶️Answer/Explanation
Answer: A
Explanation: During daytime photosynthesis removes CO₂ (purple indicator), while at night respiration produces CO₂ (yellow indicator). The indicator shows purple in low CO₂ and yellow in high CO₂.
Question 9 (B13.1)
What occurs when our eyes look from a near object in dim light to a distant object in bright light?
A Pupils constrict and lenses become thinner.
B Pupils constrict and lenses become fatter.
C Pupils dilate and lenses become thinner.
D Pupils dilate and lenses become fatter.
▶️Answer/Explanation
Answer: A
Explanation: Pupils constrict in bright light to reduce light entry. Lenses become thinner to focus distant objects (lower refractive power needed compared to near objects).
Question 10 (B15.3)
The diagram shows a section through an insect-pollinated flower.
When pollination occurs, where must the pollen grains reach?
▶️Answer/Explanation
Answer: B
Explanation: For successful pollination, pollen must reach the stigma (B), which is the receptive surface of the female reproductive part where pollen germination occurs.
Question 11 (B17.1)
Which human characteristic is not influenced by the environment?
A. blood group
B. height
C. shoe size
D. weight
▶️Answer/Explanation
Answer: A
Explanation: Blood group is determined genetically and is not influenced by environmental factors. Height, shoe size, and weight can all be affected by environmental factors such as nutrition and lifestyle.
Question 12 (B18.2)
The diagram shows the energy flow in an ecosystem:
Which group of organisms is X?
A. carnivores
B. decomposers
C. herbivores
D. producers
▶️Answer/Explanation
Answer: B
Explanation: Decomposers break down dead organic matter, returning nutrients to the ecosystem. In the energy flow diagram, decomposers would be the group that processes waste and dead material from both plants and animals.
Question 13 (B18.3)
The diagram shows the carbon cycle. Which process represents decomposition?
▶️Answer/Explanation
Answer: C
Explanation: Decomposition is the process where dead organisms are broken down by decomposers, returning carbon to the soil and atmosphere. In the diagram, this is represented by the process labeled C.
Question 14 (C12.4)
Which method is used to assess the purity of an unknown solid substance?
A. Measure its density
B. Measure its electrical conductivity
C. Measure its melting point
D. Measure its solubility in water
▶️Answer/Explanation
Answer: C
Explanation: Pure substances have sharp, well-defined melting points. Measuring the melting point is a common method to assess purity, as impurities typically lower and broaden the melting range.
Question 15 (C6.1)
Two substances, X and Y, are heated and then cooled. The observations are shown:
Which type of change occurs when X and Y are heated?
▶️Answer/Explanation
Answer: B
Explanation: Substance X undergoes a chemical change (color change indicates new substance formed), while substance Y undergoes a physical change (sublimation and recondensation of the same substance).
Question 16 (C2.6)
Diamond and graphite are different forms of the element carbon. Graphite conducts electricity. Which statement explains why diamond does not conduct electricity?
A. All of the atoms in diamond are arranged tetrahedrally.
B. All of the bond lengths in diamond are the same.
C. All of the bonds in diamond are single bonds.
D. All of the outer shell electrons in diamond are held in covalent bonds.
▶️Answer/Explanation
Answer: D
Explanation: Diamond doesn’t conduct electricity because all four outer electrons of each carbon atom are involved in strong covalent bonds, leaving no free electrons to carry charge. In graphite, only three electrons are bonded, leaving one delocalized electron per atom that can conduct electricity.
Question 17 (C3.1)
Sodium phosphate, Na3PO4, contains sodium ions, Na+. Aluminium sulfate, Al2(SO4)3, contains sulfate ions, SO42-.
What is the formula of aluminium phosphate?
A. AlPO4
B. Al(PO4)2
C. Al2(PO4)3
D. Al3(PO4)2
▶️Answer/Explanation
Answer: A
Explanation: Phosphate has a 3- charge (PO43-) and aluminum has a 3+ charge (Al3+). Therefore, one aluminum ion combines with one phosphate ion to form a neutral compound, AlPO4.
Question 18 (C4.1)
When concentrated aqueous sodium chloride is electrolysed, the remaining solution turns red litmus paper to blue.
Which substance causes this colour change?
A. chlorine
B. hydrogen
C. hydrochloric acid
D. sodium hydroxide
▶️Answer/Explanation
Answer: D
Explanation: During electrolysis of concentrated NaCl solution, NaOH is produced at the cathode. This makes the solution alkaline, turning red litmus blue. The reaction is: 2H2O + 2e– → H2 + 2OH–.
Question 19 (C5.1)
An acid is added to an alkali until the final solution is just neutral. The reaction is exothermic.
Which graph shows how the temperature changes as the acid is being added to the alkali?
▶️Answer/Explanation
Answer: C
Explanation: For an exothermic neutralization reaction, the temperature rises as acid is added until the equivalence point (neutralization), then levels off or decreases slightly as excess acid is added. Graph C shows this pattern.
Question 20 (C6.2)
Which row describes the effect of increasing temperature on collisions between particles in a chemical reaction?
| frequency of collisions | number of collisions with energy greater than activation energy | |
|---|---|---|
| A | increases | increases |
| B | increases | remains constant |
| C | remains constant | increases |
| D | remains constant | remains constant |
▶️Answer/Explanation
Answer: A
Explanation: Increasing temperature increases both the frequency of collisions (particles move faster) and the proportion of collisions with sufficient energy to overcome the activation energy barrier (particles have more kinetic energy).
Question 21 (C6.3)
Which statement about redox reactions is correct?
A. Oxidising agents are oxidised.
B. Oxidising agents lose electrons.
C. Reducing agents accept electrons.
D. Reduction is the gain of electrons.
▶️Answer/Explanation
Answer: D
Explanation: In redox reactions, reduction is defined as the gain of electrons. Oxidising agents are reduced (not oxidised) and gain electrons, while reducing agents are oxidised and lose electrons. Therefore, option D is correct.
Question 22 (C7.2)
Four oxides, W, X, Y and Z, are added separately to an acid and to an alkali. The results are shown.
| W | X | Y | Z | |
|---|---|---|---|---|
| acid | no reaction | reaction | reaction | no reaction |
| alkali | reaction | no reaction | reaction | no reaction |
Which statements about these oxides are correct?
1. Y is neutral and Z is amphoteric.
2. W is acidic and X is basic.
3. W is basic and X is neutral.
4. Y is amphoteric and Z is neutral.
A. 1 and 3
B. 1 and 4
C. 2 and 3
D. 2 and 4
▶️Answer/Explanation
Answer: D
Explanation: – W reacts with alkali but not acid → acidic oxide (2 correct) – X reacts with acid but not alkali → basic oxide (2 correct) – Y reacts with both → amphoteric oxide (4 correct) – Z reacts with neither → neutral oxide (4 correct) Therefore, statements 2 and 4 are correct.
Question 23 (C7.3)
Hydrochloric acid and sodium hydroxide neutralise each other to form water and sodium chloride. Which method is used to make the solution crystallise?
A. chromatography
B. evaporation
C. filtration
D. fractional distillation
▶️Answer/Explanation
Answer: B
Explanation: To obtain crystals of sodium chloride from the solution, evaporation is used to remove water until the solution becomes saturated and crystals begin to form. Chromatography separates mixtures, filtration removes solids, and fractional distillation separates liquids.
Question 24 (C8.1)
Francium and astatine are at the bottom of Group I and Group VII respectively.
Which statement is correct?
A. Astatine is the least reactive element in Group VII.
B. Astatine is the most volatile element in Group VII.
C. Francium has the highest melting point in Group I.
D. Francium has the lowest density in Group I.
▶️Answer/Explanation
Answer: A
Explanation: Reactivity decreases down Group VII, making astatine the least reactive halogen. Volatility decreases down the group (astatine is least volatile), and francium has the lowest melting point and highest density in Group I.
Question 25 (C9.2)
Which row describes the properties of a metal that is used to make aircraft parts?
| density | strength | resistance to corrosion | |
|---|---|---|---|
| A | high | high | low |
| B | high | low | high |
| C | low | high | high |
| D | low | low | low |
▶️Answer/Explanation
Answer: C
Explanation: Aircraft metals need low density (for weight), high strength (for durability), and high corrosion resistance (for longevity). Aluminum alloys typically meet these requirements.
Question 26 (C6.2)
When dilute sulfuric acid is added to a metal carbonate, gas M is produced.
What is M?
A. ammonia
B. carbon dioxide
C. hydrogen
D. sulfur dioxide
▶️Answer/Explanation
Answer: B
Explanation: The reaction between a metal carbonate and dilute acid produces carbon dioxide gas, water, and a salt. The general equation is: Metal carbonate + Acid → Salt + Water + CO₂.
Question 27 (C11.1)
Which statement about all of the members of a homologous series is correct?
A. They have similar chemical properties.
B. They have the same physical properties.
C. They have the same molecular formula.
D. They have the same number of carbon atoms.
▶️Answer/Explanation
Answer: A
Explanation: Members of a homologous series share similar chemical properties due to the same functional group. Their physical properties change gradually, molecular formulas differ by CH₂, and carbon numbers increase along the series.
Question 28 (P1.5.1)
A spring that obeys Hooke’s law has an unstretched length of 5.0 cm. A load of weight 0.50 N is hung from the spring and the length of the spring becomes 10.0 cm.
The load is replaced with a new load and the length of the spring becomes 15.0 cm. The spring has not passed its limit of proportionality.
What is the weight of the new load?
A. 0.50 N
B. 0.75 N
C. 1.0 N
D. 1.5 N
▶️Answer/Explanation
Answer: C
Explanation: Using Hooke’s law (F = kx): First extension = 10.0 – 5.0 = 5.0 cm with 0.50 N → k = 0.50/5.0 = 0.10 N/cm Second extension = 15.0 – 5.0 = 10.0 cm → F = 0.10 × 10.0 = 1.0 N
Question 29 (P1.7)
A chair of weight 40 N rests on four legs. Each leg has an area of contact with the floor of 10 cm².
What is the pressure on the floor due to the chair?
A. 1.0 N/cm²
B. 4.0 N/cm²
C. 400 N/cm²
D. 40 000 N/cm²
▶️Answer/Explanation
Answer: A
Explanation: Pressure = Force/Area. Total area = 4 × 10 cm² = 40 cm². Pressure = 40 N / 40 cm² = 1.0 N/cm².
Question 30 (P1.6.1)
An object X with mass 2.0 kg is moving with a speed of 4.0 m/s. Which object has kinetic energy equal to that of object X?
| mass of object/kg | speed of object m/s | |
|---|---|---|
| A | 0.50 | 16 |
| B | 1.0 | 8.0 |
| C | 8.0 | 2.0 |
| D | 16 | 1.0 |
▶️Answer/Explanation
Answer: C
Explanation: KE of X = ½ × 2.0 × (4.0)² = 16 J. Calculate KE for each option: A: ½ × 0.50 × (16)² = 64 J B: ½ × 1.0 × (8.0)² = 32 J C: ½ × 8.0 × (2.0)² = 16 J D: ½ × 16 × (1.0)² = 8 J Only option C matches.
Question 31 (P1.6.4)
A car engine transfers 80 000 kJ of energy in 5.0 minutes.
What is the output power of the engine?
A. 267 kW
B. 400 kW
C. 16 000 kW
D. 24 000 kW
▶️Answer/Explanation
Answer: A
Explanation: Power = Energy / Time
First convert 5.0 minutes to seconds: 5 × 60 = 300 s
Convert kJ to J: 80,000 kJ = 80,000,000 J
Power = 80,000,000 J / 300 s = 266,666.67 W = 267 kW (to 3 significant figures)
Question 32 (P2.1.3)
A fixed mass of gas is trapped in a container of constant volume.
The gas is now heated.
How does the pressure of the gas change and how does the speed of the gas molecules change?
| pressure of gas | speed of molecules | |
|---|---|---|
| A | decreases | decreases |
| B | decreases | increases |
| C | increases | decreases |
| D | increases | increases |
▶️Answer/Explanation
Answer: D
Explanation: When a fixed mass of gas in a constant volume is heated: 1. The pressure increases because the gas particles gain kinetic energy and collide with the container walls more frequently and with greater force. 2. The speed of the molecules increases because temperature is directly proportional to the average kinetic energy of the gas molecules.
Question 33 (P3.1)
Diagram 1 represents a wave.
Which diagram represents a wave with twice the frequency and half the amplitude of the wave in diagram 1?
The scales are the same in all the diagrams.
▶️Answer/Explanation
Answer: B
Explanation: Twice the frequency means the wave should have half the wavelength (more waves in the same time period). Half the amplitude means the peaks and troughs should be half as high/deep as the original wave. Option B correctly shows both these modifications while maintaining the same wave shape.
Question 34 (P3.4)
A sports field is next to a large school building. A student at the far side of the sports field sees a groundsman hit a pole with a hammer.
After the hammer hits the pole, the student hears two bangs.
Why does the student hear two bangs?
| first bang caused by | second bang caused by | |
|---|---|---|
| A | sound of hammer hitting pole | sound of pole hitting hammer |
| B | sound reaching the student’s left ear | sound reaching the student’s right ear |
| C | sound reaching student directly | sound reflected back from school building |
| D | sound reflected back from school building | sound reaching student directly |
▶️Answer/Explanation
Answer: C
Explanation: The student hears two bangs because sound travels both directly from the pole to the student and indirectly by reflecting off the school building. The direct sound arrives first as it travels a shorter distance, while the reflected sound takes a longer path and arrives slightly later, creating an echo effect.
Question 35 (P5.1)
An atom of an isotope of strontium (Sr) has a proton number of 38 and contains 52 neutrons.
What is the nuclide notation for this isotope?
A. \( _{38}^{52}\textrm{Sr}\)
B. \( _{38}^{90}\textrm{Sr}\)
C. \( _{52}^{38}\textrm{Sr}\)
D. \( _{52}^{90}\textrm{Sr}\)
▶️Answer/Explanation
Answer: B
Explanation: Nuclide notation is written as AZX where: – A = mass number (protons + neutrons) = 38 + 52 = 90 – Z = proton number = 38 – X = element symbol (Sr for strontium) Therefore, the correct notation is 9038Sr
Question 36 (P4.2.4)
How does the resistance of a piece of wire depend on its cross-sectional area and on its length?
| cross-sectional area | length | |
|---|---|---|
| A | directly proportional | directly proportional |
| B | directly proportional | inversely proportional |
| C | inversely proportional | directly proportional |
| D | inversely proportional | inversely proportional |
▶️Answer/Explanation
Answer: C
Explanation: The resistance (R) of a wire is given by: R = ρL/A where: – ρ = resistivity (constant for a given material) – L = length of wire – A = cross-sectional area 1. Resistance is directly proportional to length (longer wire = more resistance) 2. Resistance is inversely proportional to cross-sectional area (thicker wire = less resistance)
Question 37 (P2.3.2)
The cooling unit in a refrigerator is fitted at the top in the position shown in the diagrams.
Which diagram shows the convection current in the air in the refrigerator?
▶️Answer/Explanation
Answer: A
Explanation: In a refrigerator: 1. The cooling unit at the top cools the air nearby, making it denser. 2. This cool, dense air sinks down the sides of the refrigerator. 3. Warmer air from below rises to replace it, creating a convection current. 4. This circulation ensures even cooling throughout the refrigerator.
Question 38 (P4.3.1)
In the circuit, component X is used to control the brightness of the lamp.
What is component X?
A. an ammeter
B. a fixed resistor
C. a fuse
D. a variable resistor
▶️Answer/Explanation
Answer: D
Explanation: To control the brightness of a lamp (which depends on current), you need to be able to vary the resistance in the circuit: – A variable resistor (rheostat) allows continuous adjustment of resistance – Fixed resistor would give constant brightness – Ammeter measures current but doesn’t control it – Fuse is a safety device that breaks the circuit if current is too high Therefore, X must be a variable resistor.
Question 39 (P4.5.4)
A current-carrying wire is placed between the poles of a magnet, as shown. The current direction in the wire is shown. A force is produced on the wire.
In which labelled direction does the force act?
▶️Answer/Explanation
Answer: B
Explanation: Using Fleming’s Left-Hand Rule: 1. First finger (Field) points from N to S (left to right in diagram) 2. Second finger (Current) points in conventional current direction (left to right) 3. Thumb (Force) points downward toward S pole The force acts perpendicular to both the current and magnetic field directions.
Question 40 (P5.2.2)
Three types of ionising radiation enter a magnetic field at right angles.
Which types of radiation are deflected?
A. α and β only
B. α and γ only
C. β and γ only
D. α, β and γ
▶️Answer/Explanation
Answer: A
Explanation: In a magnetic field: 1. α particles (positively charged) are deflected one way 2. β particles (negatively charged) are deflected the opposite way 3. γ radiation (uncharged electromagnetic waves) is not deflected Therefore, only α and β radiation are deflected by magnetic fields.