Why water in a pot cools not just in a pot in any material container the liquids cools with time. The reason evaporation. but the question is why evaporation takes place and what it does it to the liquid.
In a liquid molecules have different energies(kinetic energy). The molecules which have energies greater than the activation energy undergo transformation or evaporate thereby the total energy of the system in this case the water decreases as the energy and temperature are related in fact directly proportional to temperature.The total temperature of the system decrease and makes it much cooler.
E= 3/2 KT
Where K is Boltzmann Constant, and T Temperture.
Now let us define what is activation energy.Activation energy is the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical transformation or physical transport.
so to explain the cooling process in terms of activation energy, all the molecules having energies greater than activation energy will evaporate and the total energy of the system decreases and hence the liquid cools.
Catalysts also work in the same way. When you add a catalyst to increase the rate of reaction what it does is it decreases the activation energy and therefore more molecules will participate in the reaction and thereby increasing the rate of reaction. In a similar way a reaction can be slowed by adding a negative catalyst which increases the activation energy and hence only fewer molecules will take part in the reaction.
