Chemistry

Chemistry

Problem

At 500 K500\,\text{K}, the reaction CO(g)+Cl2(g)  ⇌  COCl2(g)\text{CO}(g)+\text{Cl}_2(g)\;\rightleftharpoons\;\text{COCl}_2(g) has Kc=0.56K_c = 0.56. A mixture in a 1.0 L1.0\,\text{L} container at this temperature consists of 6 CO molecules, 6 Cl2_2 molecules, and 12 COCl2_2 molecules. The temperature is then increased so that KcK_c becomes 0.25, while the amounts of each species are momentarily unchanged. Based on a comparison of QcQ_c with the new KcK_c, predict whether the net reaction will shift toward the reactants or toward the products as equilibrium is re-established. Support your answer with appropriate reasoning.
Intuitive explanation

The key is to recognize that when conditions change, the system's reaction quotient QcQ_c stays the same initially (amounts haven't shifted yet), but the equilibrium constant KcK_c changes. By comparing the current QcQ_c to the new KcK_c, you can predict which direction the reaction must shift to restore equilibrium. Calculate QcQ_c from the given concentrations, then ask: is QcQ_c larger or smaller than the new KcK_c? If Qc>KcQ_c > K_c, the reaction shifts left (toward reactants); if Qc<KcQ_c < K_c, it shifts right (toward products).

Intuitive explanation

The key is to recognize that when conditions change, the system's reaction quotient QcQ_c stays the same initially (amounts haven't shifted yet), but the equilibrium constant KcK_c changes. By comparing the current QcQ_c to the new KcK_c, you can predict which direction the reaction must shift to restore equilibrium. Calculate QcQ_c from the given concentrations, then ask: is QcQ_c larger or smaller than the new KcK_c? If Qc>KcQ_c > K_c, the reaction shifts left (toward reactants); if Qc<KcQ_c < K_c, it shifts right (toward products).

Browse the problem library