Question 1
(a) Fig. 1.1 is a diagram of a cross-section through a vein. (Sub-topic: B9.3)
(i) Use a label and a label line on Fig. 1.1 to identify the:
- layer of muscle and elastic fibres
- lumen.
▶️Answer/Explanation
- Layer of muscle and elastic tissue labelled.
- Lumen labelled.
(ii) Name a structure that is present in veins but is not visible in Fig. 1.1. (Sub-topic: B9.3)
▶️Answer/Explanation
- Valve.
(b) Describe two ways in which the structure of capillaries is different from the structure of veins. (Sub-topic: B9.3)
▶️Answer/Explanation
- Capillaries have a narrower lumen compared to veins.
- Capillaries have thin walls, only one cell thick, whereas veins have thicker walls with muscle and elastic fibres.
- Capillaries do not contain muscular tissue or valves, unlike veins.
(c) Table 1.1 shows the names of three organs and some of the blood vessels connected to these organs. Complete Table 1.1. (Sub-topic: B9.3)
| Organ | Blood vessel taking blood to the organ | Blood vessel taking blood away from the organ |
|---|---|---|
| Heart | Vena cava | …… |
| Kidney | Renal artery | …… |
| Lung | …… | Pulmonary vein |
▶️Answer/Explanation
| Organ | Blood vessel taking blood to the organ | Blood vessel taking blood away from the organ |
|---|---|---|
| Heart | Vena cava | Aorta / Pulmonary artery |
| Kidney | Renal artery | Renal vein |
| Lung | Pulmonary artery | Pulmonary vein |
Question 2
The Periodic Table shows the elements arranged in order of proton number. A copy of the Periodic Table is shown on page 32.
(a) State the meaning of the term proton number. (Sub-topic: C2.2)
▶️Answer/Explanation
The proton number (also known as the atomic number) is the number of protons in the nucleus of an atom of an element. It determines the identity of the element and its position in the Periodic Table.
(b) Three metals, X, Y, and Z, are in Group 1 of the Periodic Table. Table 2.1 shows the observations when they are reacted separately with water. (Sub-topic: C8.2.1)
| Metal | Observation |
|---|---|
| X | Metal melts, gas released very quickly, coloured flame is seen |
| Y | Metal melts, gas released quickly |
| Z | Metal does not melt, gas released slowly |
(i) Identify the gas that is released when Group 1 metals react with water.
▶️Answer/Explanation
The gas released when Group 1 metals react with water is hydrogen (H2).
(ii) Deduce which metal, X, Y, or Z, has the greatest proton number. Explain your answer.
▶️Answer/Explanation
Metal X has the greatest proton number. This is because the reactivity of Group 1 metals increases down the group, and the observations show that X reacts most vigorously with water, indicating it is the most reactive and therefore has the highest proton number.
(iii) Use the information in Table 2.1 to place metals X, Y, and Z in order of their melting points. Explain your answer.
▶️Answer/Explanation
The order of melting points from highest to lowest is: Z > Y > X. This is because the melting point of Group 1 metals decreases down the group. Since Z does not melt, it has the highest melting point, while X melts the most easily, indicating it has the lowest melting point.
(c) Hydrogen peroxide is a colourless liquid. Aqueous hydrogen peroxide decomposes very slowly, releasing oxygen gas. A student adds solid manganese(IV) oxide to aqueous hydrogen peroxide and observes that oxygen gas is released at a much higher rate.
(i) Describe the test for oxygen gas. (Sub-topic: C12.5)
▶️Answer/Explanation
The test for oxygen gas involves inserting a glowing splint into the gas. If the splint relights, it indicates the presence of oxygen.
(ii) Describe the role of the manganese(IV) oxide in this reaction. (Sub-topic: C6.2.2)
▶️Answer/Explanation
Manganese(IV) oxide acts as a catalyst in this reaction. It speeds up the decomposition of hydrogen peroxide into water and oxygen without being consumed in the reaction.
(iii) Balance the symbol equation for the decomposition of hydrogen peroxide. (Sub-topic: C3.1)
▶️Answer/Explanation
The balanced equation for the decomposition of hydrogen peroxide is:
2H2O2 → 2H2O + O2
Question 3 (Sub-topic: P1.5.2)
(a) Fig. 3.1 shows a worker changing a lamp on a lamp post.
(i) The worker is lifted up to the top of the lamp post.
State the type of energy that has been gained by the worker when he has reached the top of the lamp post.
▶️Answer/Explanation
Gravitational potential energy.
(ii) As the worker changes the lamp, he drops his screwdriver.
State the type of energy that is gained by the screwdriver as it is falling to the ground.
▶️Answer/Explanation
Kinetic energy.
(iii) The worker applies a horizontal force of 10 N to the top of the lamp post.
The total height of the post is 10 m.
Calculate the moment of the force at the base of the post and state its units.
▶️Answer/Explanation
Moment = Force × Distance = 10 N × 10 m = 100 Nm.
Units: Nm (Newton meters).
(b) The worker switches on the lamp. The lamp emits visible light.
(i) Fig. 3.2 shows an incomplete electromagnetic spectrum.
On Fig. 3.2 write visible light in its correct position.
▶️Answer/Explanation
Visible light should be placed between ultraviolet and infrared on the electromagnetic spectrum.
(ii) Draw a line from each type of electromagnetic radiation to its use. One of the lines has been drawn for you.
▶️Answer/Explanation
Infrared → Heat sensing camera
Microwaves → Television signal transmission
Radio waves → Telephone transmission
X-rays → Airport security bag checking
(iii) Four types of electromagnetic radiation are listed in (b)(ii).
State which of these has the lowest frequency.
▶️Answer/Explanation
Radio waves.
(c) The worker drives a van for 15 minutes and travels 8 km.
Calculate the average speed of the van in m/s.
▶️Answer/Explanation
First, convert 15 minutes to seconds: 15 minutes × 60 seconds/minute = 900 seconds.
Convert 8 km to meters: 8 km × 1000 m/km = 8000 meters.
Average speed = Distance / Time = 8000 m / 900 s ≈ 8.89 m/s.
Question 4 (Sub-topic: B18.2)
(a) Fig. 4.1 shows a food web.
(i) Identify one producer shown in Fig. 4.1.
▶️Answer/Explanation
Answer: grass / dandelion (plants)
Explanation: Producers are organisms that produce their own food through photosynthesis. In the food web, grass and dandelion plants are producers as they convert sunlight into energy.
(ii) Identify one herbivore shown in Fig. 4.1.
▶️Answer/Explanation
Answer: rabbit / mouse
Explanation: Herbivores are organisms that feed on plants. In the food web, the rabbit and mouse are herbivores as they consume grass and dandelion plants.
(iii) Use information from Fig. 4.1 to complete a food chain that includes the mouse and three other organisms.
▶️Answer/Explanation
Answer: grass / dandelion plants → mouse → snake → hawk
Explanation: A food chain shows the flow of energy from one organism to another. In this case, the grass/dandelion plants are eaten by the mouse, which is then eaten by the snake, and finally, the snake is eaten by the hawk.
(b) Complete the sentences to describe why the hawk can be classed as a secondary or a tertiary consumer.
The hawk is a secondary consumer when it eats:
▶️Answer/Explanation
Answer: rabbits / mice / primary consumers
Explanation: The hawk is a secondary consumer when it eats primary consumers like rabbits or mice, which feed directly on producers.
The hawk is a tertiary consumer when it eats:
▶️Answer/Explanation
Answer: snakes / secondary consumers
Explanation: The hawk is a tertiary consumer when it eats secondary consumers like snakes, which feed on primary consumers.
(c) A disease causes a large decrease in the rabbit population. This causes a decrease in the snake population. Give two reasons why the snake population decreases.
▶️Answer/Explanation
Answer:
- As there is less food for snakes.
- Increased predation of snakes.
Explanation: The decrease in the rabbit population reduces the food supply for snakes, leading to a decline in the snake population. Additionally, with fewer rabbits, predators may turn to snakes as an alternative food source, increasing predation on snakes.
(d) State the principal source of energy for all food webs.
▶️Answer/Explanation
Answer: Sun
Explanation: The Sun is the primary source of energy for all food webs. Producers (plants) convert solar energy into chemical energy through photosynthesis, which is then passed through the food chain.
Question 5
(a) Name the type of chemical bond between: (Sub-topic: C2.4, C2.5)
- a metallic element and a non-metallic element
- two non-metallic elements.
▶️Answer/Explanation
- Ionic/electrovalent bond
- Covalent bond
(b) Fig. 5.1 shows four particle diagrams, A, B, C, and D.
(i) Carbon exists in different forms. Name the form of carbon shown in diagram A. (Sub-topic: C2.6)
▶️Answer/Explanation
Graphite
(ii) Complete the sentences to explain why diagrams A, B, and C show elements and why diagram D shows a compound. (Sub-topic: C2.1)
Diagrams A, B, and C show elements because …… …… ……
Diagram D shows a compound because …… …… ……
▶️Answer/Explanation
Diagrams A, B, and C show elements because they contain only one type of atom. Diagram D shows a compound because it shows different types of atoms bonded together.
(iii) State the formula of the compound in diagram D. (Sub-topic Code: C3.1)
▶️Answer/Explanation
C2H5O
(c) The element lead is separated from the compound lead(II) bromide using electrolysis as shown in Fig. 5.2. (Sub-topic: C4.1)
(i) Name the inert electrodes E and F in Fig. 5.2.
▶️Answer/Explanation
E: Cathode
F: Anode
(ii) The process releases a brown gas. Name the brown gas.
▶️Answer/Explanation
Bromine
Question 6
(a) Fig. 6.1 shows solar cells fitted to the roof of a house. They are connected to a washing machine.
(i) Complete the energy transfer sequence. (Sub-topic: P1.6.1)
Light from the Sun shines on the solar cells to produce …… energy.
Some of this energy is converted to …… energy in the washing machine to increase the temperature of water.
▶️Answer/Explanation
Light from the Sun shines on the solar cells to produce electrical energy.
Some of this energy is converted to thermal energy in the washing machine to increase the temperature of water.
(ii) The washing machine is operated during the night. (Sub-topic: P1.6.3)
Suggest a renewable energy source that could provide energy during the night.
▶️Answer/Explanation
A renewable energy source that could provide energy during the night is wind or geothermal energy.
(iii) The washing machine drum is turned by an electric motor. (Sub-topic: P4.5.5)
The turning effect of the motor can be increased by using a stronger magnet inside the motor.
State one other way of increasing the turning effect of the motor.
▶️Answer/Explanation
One other way of increasing the turning effect of the motor is by increasing the current flowing through the motor.
(b) The maximum current in the washing machine circuit is 10A. (Sub-topic: P4.4)
(i) State why a fuse should be fitted in the circuit of the washing machine.
▶️Answer/Explanation
A fuse should be fitted in the circuit of the washing machine to protect the circuit from overheating or catching fire in case of a fault or excessive current.
(ii) The washing machine’s fuse needs to be replaced.
Four different fuse ratings are available.
3 A 10 A 13 A 30 A
State the most appropriate fuse rating, and give a reason for your choice.
▶️Answer/Explanation
The most appropriate fuse rating is 13 A.
Reason: The fuse should be slightly higher than the maximum current (10 A) to allow normal operation but low enough to blow in case of a fault, preventing damage to the circuit.
Question 7 (Sub-topic: B6.1)
(a) Glucose is produced by photosynthesis and is stored in the leaves as starch.
Fig. 7.1 is a diagram of a leaf with green and white parts. The white part of the leaf contains no chlorophyll.
The student tests the leaf for the presence of starch.
(i) Name the solution used to test for the presence of starch.
(ii) Predict the colour of the test solution after testing each part of the leaf for starch.
colour of test solution after testing part A
colour of test solution after testing part B
▶️Answer/Explanation
(i) Iodine solution.
(ii) Part A: blue-black; Part B: orange/yellow/brown.
(b) Define the term photosynthesis using words from the list. Each word may be used once, more than once or not at all.
carbohydrates fats heat light oxygen proteins water
Photosynthesis is the process by which plants manufacture …… from raw materials using energy from ……
▶️Answer/Explanation
Photosynthesis is the process by which plants manufacture carbohydrates from raw materials using energy from light.
(c) Carbon dioxide is needed for photosynthesis. Carbon dioxide enters the leaf by diffusion.
Define diffusion. Use the word concentration in your answer.
▶️Answer/Explanation
Diffusion is the net movement of particles from a region of their higher concentration to a region of their lower concentration, as a result of their random movement.
Question 8 (Sub-topic: B7.3)
(a) A student adds dilute sulfuric acid to four different solids in test-tubes H, I, J and K, as shown in Fig. 8.1.
(i) State the test-tube in which:
- carbon dioxide gas is produced
- hydrogen gas is produced
- sodium sulfate solution is produced.
▶️Answer/Explanation
Answer:
– Carbon dioxide gas is produced in test-tube I (copper carbonate).
– Hydrogen gas is produced in test-tube J (magnesium).
– Sodium sulfate solution is produced in test-tube K (sodium hydroxide).
(ii) Suggest in which test-tube the reaction produces a blue solution. Give a reason for your answer.
▶️Answer/Explanation
Answer:
Test-tube H (copper) produces a blue solution because copper sulfate is formed, which is blue in color.
(b) Describe a chemical test to show that ammonium chloride contains ammonium ions.
▶️Answer/Explanation
Answer:
Add sodium hydroxide solution to ammonium chloride and warm the mixture. Ammonia gas will be released, which can be detected by its pungent smell or by turning damp red litmus paper blue.
(c) Dilute hydrochloric acid is added to aqueous sodium hydroxide.
Fig. 8.2 shows apparatus a student uses to investigate the change in pH as the acid is added.
The graph in Fig. 8.3 shows the results.
(i) Describe how the pH of the mixture in the beaker changes as the volume of acid added increases.
▶️Answer/Explanation
Answer:
The pH of the mixture decreases as the volume of acid added increases. Initially, the solution is alkaline (high pH), but as more acid is added, the pH decreases until it becomes neutral (pH 7) and then acidic (low pH).
(ii) Use the graph to find the volume of acid that produces a neutral solution. Explain your answer.
▶️Answer/Explanation
Answer:
The volume of acid that produces a neutral solution is 25 cm³. This is the point on the graph where the pH is 7, indicating that the solution is neutral.
(iii) Complete the word equation for the reaction that occurs in the beaker.
▶️Answer/Explanation
Answer:
hydrochloric acid + sodium hydroxide → sodium chloride + water
Question 9
(Sub-topics: P3.2.1, P3.2.2, P3.2.3)
(a) Fig. 9.1 shows a ray of light from a lamp striking the surface of an ice rink. The ice acts like a plane mirror.
(i) On Fig. 9.1, draw the normal at the point where the ray strikes the ice rink and label it with the word “normal”.
(ii) On Fig. 9.1, draw the reflected ray to show where a spectator will see the ray and label it with the words “reflected ray”.
(iii) On Fig. 9.1, mark the angle of incidence and label it with the letter “i”.
(b) The ice rink is prepared by melting the surface and freezing it again to create a smooth surface.
(i) State the temperature at which the water on the surface freezes.
(ii) A piece of ice is left to melt in a container. Complete Fig. 9.2 to show the arrangement of particles in liquid water. The diagram for ice has been done for you.
(c) Fig. 9.3 shows how the blade of an ice skate cuts a groove into the ice.
Fig. 9.4 shows a very heavy machine used to make the ice smooth again.
The machine does not cut grooves into the ice. Explain this observation.
(d) A sample of the ice was taken for analysis. The mass of the sample was 4600 g. The volume was 5000 cm³.
Calculate the density of the ice.
(e) The floor that surrounds the rink is made from rubber. Suggest why a floor made from rubber can prevent sliding.
▶️Answer/Explanation
(a) (i) The normal should be drawn perpendicular to the surface of the ice at the point where the ray strikes it. Label it “normal”.
(ii) The reflected ray should be drawn at the same angle as the incident ray but on the opposite side of the normal. Label it “reflected ray”.
(iii) The angle of incidence is the angle between the incident ray and the normal. Mark this angle and label it “i”.
(b) (i) The temperature at which water freezes is 0°C.
(ii) In liquid water, the particles should be shown as touching but arranged randomly, unlike the regular arrangement in ice.
(c) The machine does not cut grooves into the ice because it has a larger surface area in contact with the ice, which reduces the pressure exerted on the ice. The skate blade, with a smaller surface area, exerts a higher pressure, causing it to cut into the ice.
(d) Density = mass/volume = 4600 g / 5000 cm³ = 0.92 g/cm³.
(e) A rubber floor can prevent sliding because rubber has a high coefficient of friction, which provides better grip and reduces the likelihood of slipping.
Question 10 (Sub-topic: B10.1)
(a) The skin has an important role in the maintenance of body temperature.
Fig. 10.1 is a diagram of a cross-section of the skin.
Identify the parts labelled X and Y in Fig. 10.1.
▶️Answer/Explanation
X: Sweat gland
Y: Blood vessel
Detailed Solution:
(a) The skin plays a crucial role in regulating body temperature. In the diagram, part X is identified as the sweat gland, which helps in cooling the body by producing sweat. Part Y is the blood vessel, which helps in regulating temperature by either dilating to release heat or constricting to conserve heat.
(b) The graph in Fig. 10.2 shows the differences in temperature of the skin of a person during and after exercise.
(i) Describe the pattern in the results shown in Fig. 10.2. Include data to support your answer.
▶️Answer/Explanation
The skin temperature increases during exercise and decreases after exercise. The peak temperature is around 38°C at 50 minutes, after which it gradually decreases.
Detailed Solution:
(b)(i) The graph shows that during exercise, the skin temperature rises due to increased metabolic activity and heat production. The temperature peaks at around 38°C at 50 minutes, after which it gradually decreases as the body cools down post-exercise.
(ii) State two changes that occur in the skin of the person during exercise, other than changes in temperature.
▶️Answer/Explanation
1. Sweating increases to help cool the body.
2. Blood vessels near the skin surface dilate (vasodilation) to increase blood flow and heat loss.
Detailed Solution:
(b)(ii) During exercise, apart from the increase in skin temperature, the body undergoes other changes to regulate temperature. Sweating increases to facilitate evaporative cooling, and blood vessels near the skin surface dilate (vasodilation) to increase blood flow, which helps in dissipating heat.
(c) The body tries to maintain a constant internal temperature.
(i) Name the organ in the body that coordinates the maintenance of a constant internal temperature.
▶️Answer/Explanation
Brain
Detailed Solution:
(c)(i) The brain, specifically the hypothalamus, is responsible for coordinating the maintenance of a constant internal temperature. It receives signals from temperature receptors and initiates responses like sweating or shivering to regulate body temperature.
(ii) Name the term used to describe the maintenance of a constant internal environment.
▶️Answer/Explanation
Homeostasis
Detailed Solution:
(c)(ii) The term used to describe the maintenance of a constant internal environment is homeostasis. This process involves various mechanisms that keep the internal conditions stable despite changes in the external environment.
Question 11
(a) State the names and percentages of the two main gases in air. (Sub-topic: C10.2)
▶️Answer/Explanation
Answer: The two main gases in air are nitrogen (78%) and oxygen (21%).
(b) Fig. 11.1 shows the composition of two gas mixtures Y and Z. (Sub-topic: C10.2)
(i) Deduce which gas mixture, Y or Z, is natural gas. Explain your answer.
▶️Answer/Explanation
Answer: Mixture Y is natural gas because natural gas is mainly composed of methane, and mixture Y has a high percentage of methane compared to mixture Z.
(ii) Describe how gas mixture Z is tested to show it contains carbon dioxide.
▶️Answer/Explanation
Answer: To test for carbon dioxide in gas mixture Z, bubble the gas through limewater. If carbon dioxide is present, the limewater will turn milky or cloudy due to the formation of calcium carbonate.
(c) Methane and propane are used as fuels. (Sub-topic: C11.3)
(i) Fig. 11.2 shows a molecule of propane.
State why propane is described as:
- a hydrocarbon
- a saturated compound.
▶️Answer/Explanation
Answer:
- Propane is described as a hydrocarbon because it consists only of hydrogen and carbon atoms.
- Propane is described as a saturated compound because it contains only single bonds between carbon atoms, meaning it has the maximum number of hydrogen atoms possible.
(ii) Identify the compounds that are produced by the complete combustion of methane.
▶️Answer/Explanation
Answer: The compounds produced by the complete combustion of methane are carbon dioxide (CO2) and water (H2O).
Question 12
(a) Between the Sun and the Earth there is the vacuum of space.
(i) State the part of the electromagnetic spectrum mostly involved in the transfer of thermal energy by radiation. (Sub-topic: P3.3)
▶️Answer/Explanation
Infrared
(ii) It takes 8 minutes for visible light to travel from the Sun to the Earth. State how long it takes for other electromagnetic waves to travel from the Sun to the Earth. (Sub-topic: P3.1)
▶️Answer/Explanation
8 minutes
(iii) The magnetic field around the Earth protects living things from the Sun’s harmful ionising radiation. State one effect of ionising radiation on living things. (Sub-topic: P5.2.5)
▶️Answer/Explanation
Can cause cancer / cell mutations / damage to cells
(iv) Explain why the sound produced by the Sun cannot be heard on Earth. (Sub-topic: P3.4)
▶️Answer/Explanation
Sound waves need a medium to travel through, and space is a vacuum with no medium.
(b) A boy uses a thin converging lens to focus the Sun’s light rays onto a sheet of paper. (Sub-topic: P3.2.3)
(i) Complete the ray diagram in Fig. 12.1 to show what happens to the rays of light after they pass through the lens.
▶️Answer/Explanation
Two rays meet at a single point in the middle of the paper.
(ii) Name the distance labelled L in Fig. 12.1.
▶️Answer/Explanation
Focal length
(c) The boy builds a torch (flashlight) to shine light through the lens. The circuit contains a cell, a switch and a lamp all connected in series.
(i) Draw a circuit diagram for the torch. (Sub-topic: P4.3.1)
▶️Answer/Explanation
Symbols correct; cell, switch, and lamp in series.
(ii) The potential difference across the lamp is 9 V. The current flowing in the circuit is 4.5 A. Calculate the resistance of the lamp. (Sub-topic: P4.2.4)
▶️Answer/Explanation
Using Ohm’s Law: \( R = \frac{V}{I} = \frac{9}{4.5} = 2 \, \Omega \)
Question 13 (Subtopic: 15.3)
(a) Fig. 13.1 is a diagram of a flower.
Using the letters from Fig. 13.1, identify where these processes occur:
fertilisation ………
pollination. ……….
▶️Answer/Explanation
13(a) R ;
Q ;
(b) Table 13.1 shows some of the features of fertilisation and pollination.
Place ticks (✓) in the boxes to show the correct features of fertilisation and pollination.
▶️Answer/Explanation
(b) 
(c) Name one agent of pollination.
▶️Answer/Explanation
13(c) (named) insect / wind ;
(d) A gardener plants seeds to grow flowers.
Using your knowledge of seed germination, describe two ways the gardener could improve the chances of successful germination.
▶️Answer/Explanation
13(d) water the seeds ;
aerate the soil ;
keep seeds warm / germinate indoors / use greenhouse ;