Chemistry Year 12 - Module 5 - Lesson 9

Writing Keq Expressions — The Rules

Use this worksheet after reading the lesson to practise the key ideas and prove you can meet the success criteria.

Name

Date

Class

1. Key Ideas

width=device-width, initial-scale=1.0

Key facts and terms for Writing Keq Expressions — The Rules
How the main ideas in Writing Keq Expressions — The Rules connect

2. Success Criteria

By the end, you should be able to:

Key facts and terms for Writing Keq Expressions — The Rules
Where this lesson fits in Module 5
How the main ideas in Writing Keq Expressions — The Rules connect

3. Key Terms

ExcludeFor CH₃COOH(aq) ⇌ CH₃COO⁻(aq) + H⁺(aq), the Ka expression is [CH₃COO⁻][H⁺]/[CH₃COOH] — water is excluded (it is the solvent).

Dynamic equilibriumA state where forward and reverse reaction rates are equal.

Equilibrium constant (Keq)The ratio of product to reactant concentrations at equilibrium.

Le Chatelier's PrincipleA system at equilibrium shifts to minimise applied disturbances.

Reaction quotient (Q)The ratio of product to reactant concentrations at any instant.

Solubility product (Ksp)The equilibrium constant for dissolution of a sparingly soluble salt.

4. Activity: Build the Lesson Map

Use the lesson to complete the table. Keep answers brief but specific.

Prompt	Your answer
Main concept
Important example
Common mistake to avoid
How this links to the next lesson

5. Short Answer Questions

1. Explain this lesson goal in your own words: "Key facts and terms for Writing Keq Expressions — The Rules". Use one specific example from the lesson.

Band 32 marks

2. Apply this idea to a new example: "Where this lesson fits in Module 5". Show your reasoning clearly.

Band 43 marks

3. Analyse why this idea matters for understanding Writing Keq Expressions — The Rules: "How the main ideas in Writing Keq Expressions — The Rules connect".

Band 54 marks

6. Extend: Apply the Idea

Band 5/65 marks

A student gives a memorised answer about Writing Keq Expressions — The Rules but does not use evidence or reasoning.

Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.

7. Multiple Choice

1. What is the best first step when answering a question about Writing Keq Expressions — The Rules?

A. Identify the key concept being tested

B. Write every fact from memory

C. Ignore the command word

D. Skip examples and evidence

2. Which answer would show stronger understanding of Writing Keq Expressions — The Rules?

A. An answer with accurate terms and reasoning

B. A copied definition only

C. A single-word response

D. An answer with no example

3. What should you do if a question asks you to explain?

A. Link the idea to a reason or cause

B. List unrelated facts

C. Only draw a diagram

D. Write the shortest possible answer

8. Success Criteria Proof

Finish with evidence that you can do each success criterion.

Success criterion 1

Prove that you can: Key facts and terms for Writing Keq Expressions — The Rules