R2.3 How far? The extent of chemical change (HL)
13 revision questions with answers for R2.3 How far? The extent of chemical change (HL). Read them here, or play the set as a class game on the projector. Free to host, and students join with a code.
Ratio with the same form as K but using non-equilibrium concentrations?
- Equilibrium constant
- Rate constant
- Partition coefficient
- Reaction quotientRight answer
What this set covers
Equilibrium at HL: the reaction quotient Q against K, calculating Kc from equilibrium amounts, finding concentrations from K, reversing or scaling equations, and linking ΔG⦵ to K.
- Common mix-up
- Students often forget how K changes with the equation: reversing it gives 1/K and doubling the coefficients squares K.
- Revision tip
- Compare Q with K for a made-up mixture and predict the direction of change, then check with the K = 4.0 reversal and doubling examples.
All 13 questions and answers
Ratio with the same form as K but using non-equilibrium concentrations?
Answer: Reaction quotient
If Q < K, the reaction proceeds…?
Answer: To the right
If Q = K, the system is…?
Answer: At equilibrium
Kc for A ⇌ B with [A] = 0.20 and [B] = 0.80 mol dm⁻³ at equilibrium?
Answer: 4.0
Kc for H₂ + I₂ ⇌ 2HI with [H₂] = [I₂] = 0.10 and [HI] = 0.80 mol dm⁻³?
Answer: 64
1.00 mol of A in 1.00 dm³ forms 0.40 mol of B at equilibrium (A ⇌ B). Kc?
Answer: 0.67
For A ⇌ 2B, Kc = 0.50 and [A] = 2.0 mol dm⁻³ at equilibrium. [B]?
Answer: 1.0 mol dm⁻³
K for A ⇌ B is 4.0. K for B ⇌ A?
Answer: 0.25
K for A ⇌ B is 3.0. K for 2A ⇌ 2B?
Answer: 9.0
When K is very small, a reactant's equilibrium concentration is approximately its…?
Answer: Initial concentration
Equation linking ΔG⦵ to the equilibrium constant?
Answer: ΔG⦵ = −RT ln K
If ΔG⦵ for a reaction is negative, K is…?
Answer: Greater than 1
Value of K when ΔG⦵ = 0?
Answer: 1
Play it as a class game
Play this set opens it in splycr, where you can host it for your class straight away. Hosting needs no account: put the room code on the projector, and students join from a phone with the code and their first name. Each question plays as multiple choice, and the three wrong options were written for that question.