Question

A gas contained in a cylinder is compressed, the work required for compression being 5000 kj. during the process, heat interaction of 2000 kj causes the surroundings to be heated. the changes in internal energy of the gas during the process is

Answer 1

The gas is compressing the cylinder , hence the work done is negative and is given as

W = - 5000 kJ

The surroudiing is being heated , hence the heat is taken as negative and given as

Q = - 2000 kJ

U = change in iiernal energy

according to first law of thermodyanamics

Q = W + U

inserting the above values in the equation

- 2000 = - 5000 + U

U = 5000 - 2000

U = 3000 kJ

hence the internal energy change by 3000 kJ