Question

A system releases 65 kJ of heat and receives 82 kJ of work. What is ∆E? Is the process endothermic or exothermic?

Answer 1

First Law of thermodynamics:- The energy can neither be created nor be destroyed. It can be converted from from one form to another. This is also called Law of conservation of energy.

q = ΔE + w

Or

ΔE = q - w

Where q = heat

w = work

ΔE = energy of the system

It is given that

System releases 65 KJ heat it means q = -65 KJ

Work is done by the system w = +82 KJ

Now ΔE = -65 - 82 = -147KJ

ΔE = -147KJ

Endothermic or exothermic process:-

A chemical reaction or physical change is endothermic if heat is absorbed by the system from the surroundings. In the course of an endothermic process, the system gains heat from the surrounding and so the temperature decreases. The quantity of a heat q is positive.

A chemical reaction or physical change is exothermic if heat is released by the system into the surroundings. Because the surrounding is gaining the heat from the system and the temperature of the surrounding increases and the q for the exothermic reaction is negative.

Hence the answer is

the process is exothermic