Given the reaction: SO2(g) + NO2(g) = NO(g) + SO3(g) H = -42.6Kj

Question

How will the concentration of SO3 at equilibrium be effected by the following:

a) Adding more NO2(g)
b) Removing some NO(g)
c) Increasing the temperature

Answer 1

Let me rewrite the equation to include the heat content instead of using two separate equations for that.
SO2(g) + NO2(g) = NO(g) + SO3(g) + heat

Now, the long explanation of Le Chatelier's Principle is that when a system in equilibrium is subjected to a stress, the reaction will shift in such a way as to relieve the stress. The shorter way, I think is better, and it says, a system in equilibrium will try to undo what we do to it. There are only three answers to these problems. (a) reaction shifts to the right.
(b) reaction shifts to the left.
(c) reaction doesn't shift at all.
a) if NO2 is added. The system will try to use up NO2. How can it do that. The reaction will shift to the right because that uses up NO2.
(b) removing NO. The system will try to add NO to replace what we've removed. How can it do that? By shifting to the right.
When shifting to the right, NO is increased, SO3 is increased, heat is increased, SO2 is decreased, and NO2 is decreased. I will leave the last one for you.