Year 10 Science · Unit 2 · Lesson 20

Unit Synthesis and Depth Study Preparation

Challenge Worksheet

Name
Date
Class

Learning Goals

Go Deeper

Find the mistakes

A student wrote these five statements in their unit revision notes

  1. "You can balance a chemical equation by changing the subscripts in the formula, for example, changing H₂O to H₃O."
  2. "Catalysts are consumed during a chemical reaction, they provide the energy needed to start the reaction."
  3. "Neutralisation produces only salt, an acid and a base react to form an ionic compound."
  4. "Endothermic reactions are always slower than exothermic reactions because they need to absorb energy first."
  5. "Acid rain is caused entirely by carbon dioxide, CO₂ dissolves in rainwater and makes it acidic."

1. Identify the error in statement 1 and write the correct rule for balancing equations.

Challenge 1 mark

2. Correct statement 2. Explain what catalysts actually do and what happens to them during a reaction.

Challenge 1 mark

3. Correct statement 3. What does neutralisation also produce besides a salt? Give an example equation.

Challenge 1 mark

Go Deeper (continued)

4. Correct statement 4. Explain why the energy change in a reaction (endo or exo) does not directly determine its speed. Give an example of a fast endothermic or slow exothermic reaction.

Challenge 2 marks

5. Correct statement 5. Name the two gases (other than CO₂) primarily responsible for acid rain. Write one word equation showing how one of them forms an acid in rainwater.

Challenge 2 marks

Show What You Know

1. Explain in two or three sentences why the Haber process conditions (400–500°C, ~200 atm, iron catalyst) represent a compromise rather than the optimal conditions for either maximum rate or maximum yield.

Challenge 3 marks

Wrap Up

Which chemical reaction type has the greatest impact on the environment, and what should be done about it?

HSCScience · Year 10 Science · Unit 2 · Lesson 20 · Challenge Worksheet