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Chemical Equilibrium part 4 Post-module assessment

Posted: Sat Jan 19, 2019 2:03 pm
by Hailey Boehm 2H
Question 12 on the post-module assessment states the following:
12. State whether the equilibrium shifts towards products, reactants, or neither when the given change occurs.
CO2(g) + H2(g) ⇌ CO(g) + H2O(g) delta H° = +41.0 kJ.mol-1
i. The amount of carbon monoxide is increased
ii. The pressure on the system is increased.

A. i = Reactants ii = Products

B. i = Products ii = Reactants

C. i = Reactants ii = Neither

D. i = Products ii = Neither

I thought the answer was A, but this answer is wrong. Can someone explain what the right answer is and why? Thank you!

Re: Chemical Equilibrium part 4 Post-module assessment

Posted: Sat Jan 19, 2019 2:32 pm
by Kate_Santoso_4F
The correct answer should be C. If you increase the amount of carbon monoxide, the equilibrium will shift towards reactants since change in concentration of a chemical reaction at equilibrium represents a fixed P/R ratio. Therefore, more reactant will form until the original P/R ratio is attained (same K). If the pressure on the system is increased by decreasing volume, the equilibrium will shift to the side with more moles of gas. In this problem, there are exactly 2 moles of gas on the reactant and products side so there will be no equilibrium shift.