Success Homeschool

Year 10 Science · Rates of reaction

Name: ______________________

Date: ____________

1. According to collision theory, what must happen for particles to react?
- ☐ (a) They must be the same colour
- ☐ (b) They must collide with enough energy and the right orientation
- ☐ (c) They must be in a solid
- ☐ (d) They must be heated above 100 °C
2. Which change would slow down the reaction of a tablet in water?
- ☐ (a) Crushing the tablet
- ☐ (b) Using warmer water
- ☐ (c) Using colder water
- ☐ (d) Stirring the water
3. What does a catalyst do?
- ☐ (a) Lowers the activation energy and is not used up
- ☐ (b) Raises the activation energy
- ☐ (c) Is used up as a reactant
- ☐ (d) Makes the reaction produce more product
4. Why are fine sawdust and flour dangerous in factories?
- ☐ (a) They are heavy
- ☐ (b) They are always wet
- ☐ (c) They are acidic
- ☐ (d) Their huge surface area can make them burn explosively
5. In the temperature investigation, which is a controlled variable?
- ☐ (a) Water temperature
- ☐ (b) Time for fizzing to stop
- ☐ (c) Volume of water
- ☐ (d) Reaction rate
6. Trials took 40 s, 44 s and 42 s. What is the average time in seconds? (number)
7. Which gas causes the fizz when an effervescent tablet dissolves?
8. What name is given to biological catalysts?

Answer sheet

1. They must collide with enough energy and the right orientation — Successful collisions need at least the activation energy and the right orientation.
2. Using colder water — Lower temperature means slower particles and fewer successful collisions.
3. Lowers the activation energy and is not used up — Catalysts provide a lower-energy pathway and remain at the end.
4. Their huge surface area can make them burn explosively — Fine powders expose enormous surface area to oxygen, so they can ignite very rapidly.
5. Volume of water — Volume of water must be kept the same; temperature is the independent variable.
6. 42 — (40 + 44 + 42) ÷ 3 = 126 ÷ 3 = 42 s.
7. carbon dioxide — The acid reacts with sodium bicarbonate to release carbon dioxide.
8. enzymes — Enzymes are proteins that catalyse reactions in living things.