Apentix/AP Chemistry/Unit 7: Equilibrium/Question
AP Chemistryeasymcq1 pt

How does the reaction quotient Q differ from the equilibrium constant K?

A.Q can be evaluated from concentrations at any stage of a reaction, while K applies only at equilibrium
B.Q uses partial pressures exclusively while K always uses molar concentrations
C.Q is fixed at a given temperature while K varies continuously as the reaction proceeds
D.Q describes only reactions involving gases while K describes only aqueous reactions

Explanation

Core Concept

Both Q and K use the same products-over-reactants expression, but they are sampled under different conditions. Q describes the ratio at whatever moment concentrations are measured, whether the reaction just started or is midway. K is the single value Q reaches once forward and reverse rates become equal at equilibrium. Comparing the measured Q against K predicts which direction the net reaction must run.

Correct Answer

AQ can be evaluated from concentrations at any stage of a reaction, while K applies only at equilibrium

More Unit 7: Equilibrium practice questions

Try a random question →

Practice more AP Chemistry questions with full explanations

Practice Unit 7: Equilibrium Questions →