Question

For the equilibrium: N2(g)+O2(g)+heat<--> 2NO(g)
Using Le chateliers Principle, select the conditions that would favour the best yields of NO

Answer 1

We'll consider the following condition changes on the reaction:

Pressure: Le Chatelier's Principle states that if we were to change the pressure of a system at equilibrium, then the system would counteract this change and produce either more (pressure drop) or less (pressure increase) molecules. However,as both sides of the equilibrium contains to molecules (two NO's; 1 N2 and 1 O2), then the system can't move to counteract the pressure change, so no particular condition is favored here.

Temperature: As we have to add heat to the system to form NO, the forward reaction is endothermic. So, if we add heat, the system will counteract the temperature increase by taking in the heat and using it to form more products by the heat-absorbing forward reaction to create NO.

Concentration: Similarly, if we increase the concentration of either O2 or N2 (whichever is the limiting reactant to the amount of the product we form in the forward reaction), then the system will counteract by using these additional reagents to form more NO.

So overall, according to Le Chatelier's Principle, an increase in temperature and in O2 / N2 concentration will lead to an increased yield of NO.