Combined Science Paper 2 November 2024

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1. AA face mask that filters dust and fumes out of the air breathed in
2. BA pair of safety goggles that seal closely around the eyes
3. CA cotton laboratory coat that covers the arms and the body
4. DA pair of rubber gloves that cover the hands and the wrists

1. Aburns the skin on contact and leaves behind a deep painful wound.
2. Bcatches fire easily when it meets a flame, a spark or strong heat.
3. Cgives off a vapour that is poisonous when it is breathed in deeply.
4. Dreacts with water and gives out a large amount of heat as it does so.

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1. AEat at the bench where you are working, and taste a chemical in order to identify it.
2. BPoint a heated test tube away from your own face, and run when fetching apparatus.
3. CWear a laboratory coat during practical work, and report every spill and accident at once.
4. DTry out experiments of your own design, and pour leftover chemicals back into the bottle.

1. Aprevents burns, cuts, poisoning and fires among the learners and the staff.
2. Bmakes the result of every experiment come out much closer to the true value.
3. Cshortens the time a practical lesson takes, so that more work is covered.
4. Dreduces the amount of chemicals a school has to buy for each practical.

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1. Arain lowers the body temperature, so bacteria in the stomach multiply much faster.
2. Brain water washes sewage into wells and rivers, so drinking water carries the bacteria.
3. Cthe cool damp air weakens the lungs, letting the bacteria enter through the airways.
4. Dmosquitoes breed in the standing water and pass the bacteria on when they bite.

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1. Agiving a vaccine once the symptoms appear, which clears the infection.
2. Boperating to remove the infected tissue before the virus can spread.
3. Cgiving a course of antibiotics, which kills the virus within a few days.
4. Disolating the patient and giving fluids and other supportive care.

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1. AA high boiling point, and it conducts electricity as a solid but not once it melts.
2. BA low melting point, and it conducts electricity as a solid but not when molten.
3. CA low boiling point, and it burns in air to give a gas that dissolves in water.
4. DA high melting point, and it conducts electricity when molten or dissolved in water.

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Answer this when you sit the paper.

1. Ametal P + hydrochloric acid gives P chloride + oxygen
2. Bmetal P + hydrochloric acid gives P hydroxide + hydrogen
3. Cmetal P + hydrochloric acid gives P chloride + water
4. Dmetal P + hydrochloric acid gives P chloride + hydrogen

1. AHold a glowing splint inside the tube; the splint relights if the gas is present.
2. BBubble it through limewater, which turns milky if the gas is present.
3. CHold damp red litmus paper in it, which turns blue if the gas is present.
4. DHold a lighted splint at the mouth of the tube; the gas burns with a squeaky pop.

1. AZinc, because it reacts with the acid at a rate far too slow to see in one lesson.
2. BCalcium, because it reacts with the water in the acid before the acid itself.
3. CCopper, because it lies below hydrogen in the reactivity series and cannot displace it.
4. DMagnesium, because it forms a layer of oxide that seals its surface from the acid.

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Answer this when you sit the paper.

Answer this when you sit the paper.

1. Athe vacuum holds still air, which is a poor conductor and so traps the heat inside.
2. Bthe vacuum has no particles, so heat cannot cross it by conduction or convection.
3. Cthe vacuum reflects the heat radiation back into the liquid held in the flask.
4. Dthe vacuum keeps the pressure low, so the liquid inside cools down more slowly.

1. Ais a poor conductor, so the heat stays in the water inside the pipes.
2. Breflects heat radiation back into the pipes, warming the coolant again.
3. Cis a good emitter of heat, so the coolant loses its heat quickly.
4. Dabsorbs less heat from the sun, which keeps the engine coolant cool.

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Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Ainversely proportional to the voltage across it, at a constant temperature.
2. Bequal to the voltage across it multiplied by the resistance of the wire.
3. Cindependent of the voltage across it once the wire has warmed up fully.
4. Ddirectly proportional to the voltage across it, at a constant temperature.

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Answer this when you sit the paper.

Answer this when you sit the paper.

1. ARickets, in which the leg bones soften and bend under the body's weight.
2. BGoitre, in which the thyroid gland swells into a lump at the front of the neck.
3. CEmphysema, in which the alveoli walls break down and gas exchange falls.
4. DAnaemia, in which too little iron in the diet lowers the haemoglobin made.

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1. Anarrows the airways, so that air is forced through them at a higher speed.
2. Bstains the teeth and the fingers a yellow brown colour over the years.
3. Cdissolves the walls of the alveoli, so that the lungs hold much less air.
4. Dcombines with haemoglobin, so that the blood carries much less oxygen.

1. AHallucinations, with poor memory and difficulty in concentrating.
2. BFaster reactions and sharper coordination while driving a vehicle.
3. CA rise in the number of red blood cells made in the bone marrow.
4. DA drop in body temperature that brings on shivering and cramps.

1. AThe kidneys, which filter the drug out of the blood before it acts.
2. BThe lungs, which take the smoke in and become irritated and inflamed.
3. CThe stomach, where the smoke is swallowed and digested with the food.
4. DThe skin, which the smoke passes through as it leaves the body again.

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1. AA: lymphocyte, B: phagocyte, C: red blood cell
2. BA: red blood cell, B: phagocyte, C: lymphocyte
3. CA: phagocyte, B: red blood cell, C: lymphocyte
4. DA: phagocyte, B: lymphocyte, C: red blood cell

Answer this when you sit the paper.

1. AA lymphocyte engulfs and digests pathogens, while a phagocyte produces antibodies.
2. BA lymphocyte carries oxygen to the tissues, while a phagocyte clots the blood.
3. CA lymphocyte produces antibodies, while a phagocyte engulfs and digests pathogens.
4. DA lymphocyte clots blood at a wound, while a phagocyte carries carbon dioxide.

1. Acarry oxygen to the wound so that the damaged tissue can be repaired.
2. Bproduce antibodies that stick the edges of the wound back together.
3. Cdissolve the fibrin in the blood so that it can flow past the wound.
4. Dclot the blood to stop the bleeding and seal the wound against pathogens.

1. AIt breaks urea down into water and salts inside the red blood cells.
2. BIt stores extra glucose in the plasma as glycogen until the muscles call for it.
3. CIt carries heat from the liver and muscles to the skin, where the heat is lost.
4. DIt makes the hormone insulin inside the plasma each time glucose levels rise.

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1. AA: filament, B: stigma
2. BA: stigma, B: anther
3. CA: anther, B: stigma
4. DA: anther, B: ovary

1. AThe anther produces pollen grains, and the stigma receives pollen grains.
2. BThe anther receives pollen grains, and the stigma produces pollen grains.
3. CThe anther holds the ovules, and the stigma grows into the wall of the fruit.
4. DThe anther makes nectar for insects, and the stigma holds the pollen tube.

1. AThe petals close over the anthers at night so as to keep the pollen grains dry.
2. BThe petals shade the nectar so that it does not dry up in the midday heat.
3. CThe petals catch the wind so that pollen is blown from flower to flower.
4. DThe petals attract insects to the flower, and the insects carry the pollen away.

1. AThe grains cling to the body of a visiting insect and are carried to another flower.
2. BThe grains stick to each other in large clumps that fall straight onto the stigma.
3. CThe grains hold water on their surface, which keeps them alive in dry weather.
4. DThe grains float on the wind more easily than the smooth grains of grasses do.

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1. AW and Z
2. BX and Y
3. CY and Z
4. DW and X

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Answer this when you sit the paper.

1. ABoth give out heat energy, but melting frees the particles while boiling fixes them in place.
2. BBoth take in heat energy, but melting happens at the melting point and boiling at the boiling point.
3. CBoth give out heat energy, and both of them happen at the melting point of the substance.
4. DBoth take in heat energy, and both of them leave the particles still touching one another.

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Answer this when you sit the paper.

1. Asteam particles move fast and spread out, and their collisions push the lid up.
2. Bthe water expands as it is heated until it fills the pot right up to the lid.
3. Cthe lid becomes lighter as it is heated, so a small force is enough to lift it.
4. Dthe air above the water is drawn out of the pot, and the lid is sucked upwards.

1. Aclosely packed in fixed positions, where they vibrate but do not move about.
2. Bspread out in a regular pattern with large gaps of air in between them.
3. Cfar apart and moving freely, so they take the shape of the container.
4. Dclose together but able to slide past one another in any direction.

1. Aa substance that has been dissolved in water to give a clear solution.
2. Btwo or more substances chemically joined together in a fixed ratio by mass.
3. Ctwo or more substances mixed together but not chemically combined.
4. Da single substance made up of atoms that all share the same proton number.

1. AIron sulphide and carbon dioxide
2. BSea water and carbon dioxide
3. CAir and sea water
4. DArgon and oxygen

Answer this when you sit the paper.

1. Ahas one electron in its outer shell, which it loses in order to become stable.
2. Bis lighter than air, so it rises and does not meet the other elements.
3. Cis found uncombined in air, which shows it has no electrons left to share.
4. Dhas a full outer shell of eight electrons, so it is stable and unreactive.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Aeach component has a different colour, and darker colours are held back by the paper.
2. Beach component dissolves in the solvent to a different extent, so they travel at different speeds.
3. Cthe heavier components sink to the baseline while the lighter ones float to the top.
4. Dthe solvent dries at different rates along the paper, leaving the spots behind it.

1. Asupply the oxygen the glucose needs before it can break down into ethanol.
2. Braise the temperature of the mixture so that all of the glucose dissolves in it.
3. Csupply the enzymes that break glucose down into ethanol and carbon dioxide.
4. Dabsorb the carbon dioxide so that the ethanol formed does not turn sour.

1. Aglucose gives ethanol + carbon dioxide
2. Bglucose + oxygen gives ethanol + water
3. Cstarch gives ethanol + oxygen
4. Dethanol + oxygen gives glucose + carbon dioxide

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Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. AMass is measured in newtons, while weight is measured in kilograms.
2. BMass is the amount of matter in a body, while weight is the pull of gravity on it.
3. CMass changes with the strength of gravity, while weight stays the same everywhere.
4. DMass is the pull of gravity on a body, while weight is the amount of matter in it.

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1. Astays at 12 N, because the amount of matter inside the box has not changed at all.
2. Bfalls to zero, because a body resting on the moon's surface floats freely.
3. Cincreases, because there is no atmosphere on the moon pressing down on it.
4. Ddecreases, because the gravitational pull of the moon on the box is weaker.

1. Athe tendency of a body to resist a change in its state of rest or motion.
2. Bthe force that a moving body exerts on anything that blocks its path.
3. Cthe rate at which the velocity of a moving body changes with the time taken.
4. Dthe energy stored in a body because of the speed at which it moves.

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. A200 Pa, because pressure in an enclosed fluid is passed on equally throughout it.
2. B400 Pa, because the fluid doubles the pressure as it passes along the pipe.
3. C0 Pa, because the liquid absorbs the pressure before it reaches piston B.
4. D100 Pa, because the pressure is shared out equally between the two pistons.

1. Aincreases in volume, so its pressure rises above atmospheric pressure.
2. Bstays at the same volume, so its pressure is unchanged as the piston moves.
3. Cincreases in volume, so its pressure falls below atmospheric pressure.
4. Ddecreases in volume, so its pressure rises above atmospheric pressure.

1. Aatmospheric pressure outside pushes air past the cup washer into the barrel.
2. Bthe piston drags the air along behind it through the hose from the tyre.
3. Cthe barrel cools as it stretches, and cold air is drawn in to fill the space.
4. Dthe tyre valve opens and lets air flow back out of the tyre into the barrel.

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Answer this when you sit the paper.

1. AA telephone needs a network of base stations, while a cell phone needs one cable.
2. BA telephone is fixed and uses cables, while a cell phone is portable and uses radio waves.
3. CA telephone sends sound as light pulses, while a cell phone sends it as sound waves.
4. DA telephone runs on a rechargeable battery, while a cell phone is powered by its line.

1. Athe sound waves travel along the wire unchanged and are simply made louder at the earpiece.
2. Bthe mouthpiece changes sound waves into electrical signals, and the earpiece changes them back.
3. Cthe mouthpiece changes sound waves into radio waves, and the earpiece changes them back.
4. Dthe mouthpiece changes electrical signals into sound waves, and the earpiece changes them back.

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Answer this when you sit the paper.

1. AThe signal is changed into pulses of light that pass along the glass core by total internal reflection.
2. BThe signal is changed into sound waves that echo from one end of the fibre to the other.
3. CThe signal is changed into radio waves that are beamed along the plastic core of the cable.
4. DThe signal travels as an electric current along a thin copper wire inside the glass cladding.

1. AIt carries an electric current as well as data, so it can power a device too.
2. BIt bends around sharp corners more tightly than a copper cable is able to.
3. CIt carries far more data, and electrical interference does not affect it.
4. DIt costs less to make, and a break in it can be joined again with simple tools.