H2 Chemistry Notes: CORE IDEA 3, Topic 9 - Chemical Equilibria

Q: What does H2 Chemistry Notes: CORE IDEA 3, Topic 9 - Chemical Equilibria cover?
A: Master equilibrium constants, Le Chatelier shifts, and quantitative problem-solving for Core Idea 3 (Chemical Equilibria) in the 2026 H2 Chemistry syllabus.

Equilibrium mastery blends conceptual understanding with algebraic manipulation. This note covers K_c, K_p, reaction quotient reasoning, and Le Chatelier justifications tailored for the 2026 exam style.

Supplement with practice resources from https://eclatinstitute.sg/blog/h2-chemistry-notes.

Status: SEAB H2 Chemistry (9729, first exam 2026) syllabus and Chemistry Data Booklet last checked 2025-11-29 (syllabus PDF last modified 2024-07-17; booklet last modified 2024-12-17). Core Idea 3 Topic 9 scope remains unchanged.

1 Defining Equilibrium Constants

For reaction $\ce{aA + bB \leftrightharpoons cC + dD}$:

$$K_c = \frac{[C]^c [D]^d}{[A]^a [B]^b}$$