when heated, carbon monoxide reacts to water to produce carbon dioxide and hydrogen CO(g)+H2O(g) ---> CO2(g)+H2(g)=heat. For each of the following changes at equilibrium, indicate whether the equilibrium shifts in the direction of products, reactants, or does not change:

Question

1) decreasing the temperature
2) adding some H2(g)
3) removing more CO2(g)
4) adding some H2O(g)
5) decreasing the volume of the container

Answer 1

CO(g)+H2O(g) ---> CO2(g)+H2(g) + heat
This question is all about Le Chatelier's Principle. I can give you the esoteric wording of the principle in full and it really sounds great; however, most students don't grasp it so let me give you the man on the street version. Simple. When you have a system at equilibrium and you do something to it, the system will try to undo what you did to it. I'll do one or
two for you and leave the remainder for you.
1) decreasing the temperature
CO(g)+H2O(g) ---> CO2(g)+H2(g) + heat
You see heat is produced by the reaction. If you take away heat it will shift in such as way so as to undo it; i.e. it will heat things up. How can it do that. It can cause more reactants to produce more heat. Simple. So the rxn shifts to the right.

2) adding some H2(g)
CO(g)+H2O(g) ---> CO2(g)+H2(g) + heat
Look at the equation. If you ADD H2, now it has too much so the reaction will get rid of added H2. How can it do that? Simple. It can use it up. How can it do that. The reaction will shift to the left so that the products are used up to form more reactants. Some H2 disappears that way. Shift to the left.
Students often have a difficult time understanding Le Chatelier's Principle but it makes it easier if we put it into simpler terms. Post your thoughts and work if you have further questions.