This set mixes biology, chemistry and physics with calculation, explanation and planning tasks, with no topic labels.
All data is invented. Try each question first, then open the answer. Part of mixed original practice.
Use the scientific investigation critic for questions that describe an experiment, and the error-log lesson to record what you miss. A suggested scoring habit: tick each question as full, partial or missed, then count by skill.
Questions
1. A trolley travels 150 m in 20 s. Calculate its average speed.
Show answer
speed = distance ÷ time = 150 m ÷ 20 s = 7.5 m/s. Check: 7.5 × 20 = 150.
2. A force of 15 N moves a box 4.0 m in the direction of the force. Calculate the work done.
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work done = force × distance = 15 N × 4.0 m = 60 J. Check: 60 ÷ 4.0 = 15.
3. A metal block has mass 54 g and volume 20 cm³. Calculate its density.
Show answer
density = mass ÷ volume = 54 g ÷ 20 cm³ = 2.7 g/cm³. Check: 2.7 × 20 = 54.
4. Powdered chalk reacts faster with acid than a single lump of the same mass. Explain why.
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The powder has a larger surface area exposed to the acid. More particles can collide with acid particles each second, so there are more successful collisions per second and the reaction is faster.
5. A plant cell is placed in a concentrated salt solution and shrinks. Explain this using osmosis.
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The water concentration is higher inside the cell than in the salt solution. Water moves out of the cell across the partially permeable membrane by osmosis, so the cell loses volume and shrinks.
6. Name the main model that explains each observation. (a) Perfume smell spreads across a room. (b) A cooking pot handle warms from the base. (c) A phone gets warm during charging.
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(a) Particle model, diffusion. (b) Particle model of conduction, vibrating particles pass energy along. (c) Energy transfer, some electrical energy is transferred as thermal energy to the surroundings.
7. A solution contains 4.0 g of salt dissolved in 250 cm³ of water. Calculate the concentration in g/dm³.
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250 cm³ = 0.25 dm³. Concentration = 4.0 g ÷ 0.25 dm³ = 16 g/dm³. Check: 16 × 0.25 = 4.0.
8. A student lost marks on 15 questions: 6 for units, 4 graph reading, 5 recall. What percentage is units?
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6 + 4 + 5 = 15. Units: 6 ÷ 15 = 0.40, so 40%. Units is the largest group, so it is the first skill to drill.
9. Plan a 75-minute session: 10 min warm-up, 15 min review, and the rest split biology : chemistry : physics in the ratio 1 : 2 : 2.
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Mixed block = 75 − 10 − 15 = 50 min. Ratio 1 + 2 + 2 = 5 parts, so one part = 10 min. Biology 10 min, chemistry 20 min, physics 20 min. Check: 10 + 20 + 20 = 50.
10. A set has 12 marks per science. Scores: biology 9, chemistry 7, physics 4. Give the total percentage and the weakest section’s percentage, to the nearest whole number.
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Total = 9 + 7 + 4 = 20 out of 36. 20 ÷ 36 = 0.5556, so 56%. Weakest is physics: 4 ÷ 12 = 0.3333, so 33%. The total hides a physics section that needs the most attention.
If you got these wrong
| Where you lost marks | Go to |
|---|---|
| Questions 1 to 3: equation, substitution or unit | Switch between explanation and calculation |
| Questions 4 to 6: unsure which idea to use | Identify the science model |
| Question 8: sorting your mistakes | Review errors by skill |
| Question 9: planning time | Build a balanced repeat session |
| Question 10: reading section scores | Avoid using one strength to ignore another |
Question 7 combines a unit conversion with a calculation, so revisit the equation and the unit check in the first lesson.
If the same errors return after a second attempt, online one-to-one Combined Science tuition lets a teacher watch your reasoning as you work.