DP Chemistry (first assessment 2025)
Question 21N.1A.HL.TZ0.22
| Date | November 2021 | Marks available | [Maximum mark: 1] | Reference code | 21N.1A.HL.TZ0.22 |
| Level | HL | Paper | 1A | Time zone | TZ0 |
| Command term | Determine | Question number | 22 | Adapted from | N/A |
22.
[Maximum mark: 1]
21N.1A.HL.TZ0.22
A reversible reaction has a reaction quotient, Q, of 4.5 and equilibrium constant, Kc, of 6.2.
2A (g) A2 (g)
Which statement describes the reaction at this time?
A. The system has reached equilibrium.
B. The rate of the forward reaction is greater than the rate of the reverse reaction.
C. The concentration of reactant is greater than the concentration of product.
D. At equilibrium, the concentration of reactant is greater than the concentration of product.
[1]
Markscheme
B
Syllabus sections
Reactivity 2. How much, how fast and how far? » Reactivity 2.3—How far? The extent of chemical change » Reactivity 2.3.5—The reaction quotient, Q, is calculated using the equilibrium expression with nonequilibrium concentrations of reactants and products. Calculate the reaction quotient Q from the concentrations of reactants and products at a particular time, and determine the direction in which the reaction will proceed to reach equilibrium.