Change occur in the heat energy of molecules during condensation process. The molecules of gas releases its heat energy and converted into liquid state. With this heat energy, they are active and escape from each other but when the heat energy is removed from them, the attractive forces between these gas molecules are formed which convert them into liquid state so change in heat energy occur in the condensation process.
On stage one binding of a substrate occurs (and also the geometry of active site may change) and water comes to the site. On stage two the hydrolisis takes place and on stage 3 products deabsorb from the enzyme.
