Question

When a system absorbs heat,the molecules start moving faster because kinetic energy increases,hence disorder increases. For the same amount of heat absorbed at lower temperature,the disorder is more than at higher temperature.why?explain.

Answer 1

when any substance absorbs heat, the vibration of particles(molecules) in that substance increases. this vibration is created due to collision of particles. so by heating , vibration increase, that means the velocity of particles (between collisions) increases. So thus velocity increases, means kinetic energy increases. when these things increases the disordering of molecules will be more and increases when we increases heat. That is, more powerfull collisions will kick molecules far appart and the order of system will loose as heat increases.

Also the last sentence says that, the disordering(Entropy) will be very high when you add some amount of heat to substance at low temperature than you add same heat to same substance at hign temperature.This can be explained as follows:

We assume an heat transfert is done in a high temperature environment, which means the entropy of this environment is already high since particles are already more agitated and that the energy is dispersed in a disorded way. Now if we imagine the same heat transfert in a low temperature environment, where the entropy is initially lower, we could say that the impact on the entropy of this heat transfert is more important than the same heat transfert in the high temperature environment since the energy that has been transfered in the low temperature environment makes up a greater part of the overall energy.

for eg:

If we have the high temperature environment with an initial energy of 100 and the low temperature environment with an initial energy of 10 (no matter the units, the one you want). If the energy transfert is of 5 in the same units then we can calculate that this heat transfert increases the energy in the high energy environment by 5% and increases the energy by 50% in the low energy environment. So we see that the same heat transfert influences more the low temperature environment than the high temperature one.