If we burn a fuel, the reaction goes to completion and it cannot be [?].

Many reactions are , so its possible to get a backward reaction as well as a reaction. If we carry out the reaction in a closed container, we have a system. The of the forward reaction and the rate of the backwards reaction are both the . The system is in balance, or in .

We can change the equilibrium by heating the container. If the forward reaction is , the reaction will move in a direction that makes more reactants. If it's , more products are made.

In reactions involving , an increase in will favour the side with fewer gas molecules.

speed up the rate of reaction, but do not affect the equilibrium point.