Question

Nitrogen gas and oxygen gas react according to the following equation:
Energy + N2(g) + O2(g) -><- 2NO(g)
Gas and oxygen gas are placed in a sealed container and aren't allowed to reach equilibrium. What effect will cooling system have ?

Answer 1

A. It will add more NO(g) to the system
B. It will increase the concentration of N2(g)
C. It will decrease the rate of both the forward in the reverse reaction
D. It will shift the equilibrium to the right

Answer 2

For a reaction: \(\large Energy~ +~ N_{2~(g)} + O_{2~(g)} \rightleftharpoons 2NO_{(g)}\)

We can write the equilibrium expression as so:

\(\huge \sf K=\dfrac{[product]}{[reactants]}=\dfrac{[NO]^2}{[N_2][O_2]}\)

Once the equilibrium concentrations are established, environmental or chemical changes (often called \(stresses\)) to a system will cause these concentrations to change - "equilibrium shift". Watch this video on Le Chatelier's principle:

https://www.youtube.com/watch?v=PciV_Wuh9V8

For your question, energy is needed for the (endothermic) process to occur in the forward direction, if you cool (or remove heat) the equilibrium will shift to the left, back towards the reactants.

Feel free to ask if you have doubts

Answer 3

Thank you! @aaronq

Answer 4

no problem !