Question

prove that change of internal energy is equal to heat.

Answer 1

Answer:

At constant volume, the heat of reaction is equal to the change in the internal energy of the system.

Answer 2

Answer:

Heat supplied to a system is equal to the increase in its internal energy only if there is no external work done by the system. In other words, only in the case of an isochoric process where no work is done

Actually, isochoric process is a process in which volume of the system is held constant. Since work is given by (Pressure x Volume change), so constant volume means no change in the volume. So delta V is zero and what you get is no work.

Hence, all the heat supplied increases temperature of the system, thereby increasing the internal energy

Explanation: