Le Chatelier's principle
It is used to see the effects of relations between concentration, pressure, and temperature. If a change of condition is added onto a system at equilibrium, the equilibrium position will shift in the direction that wants to reduce that change.
Equilibrium is measured by concentration of a chemistry substance. If there is more concentration, the extra material must be used up to try to set the change back at equilibrium. It tries to fill the void.
If heat is added, the system moves away from heat so it can use it up. In an endothermic reaction, if temperature is increased then the products will increase in order to stabilize this change(stress) in the reaction. In an exothermic reaction it's in abundance in its products e.g.energy. If temperature is increased then the reactants will increase to balance out reaction.