Question

A system absorbs 191 kJkJ of heat and the surroundings do 120 kJkJ of work on the system. Part A What is the change in internal energy of the system?

Answer 1

Answer: the change in internal energy of the system is 311 kJ

Explanation:

Given that;

A system absorbs a heat dQ = 191 kJ

And the the surroundings do work on the system dW = 120 kJ

change in internal energy of the system = ?

We take a look at the first law of thermodynamic

Initially the system absorbs energy ( dQ =1 91 kJ) as heat.

Then the surroundings do work (dW = 120kJ) on the system,

Hence the system gains 120 kJ more.

The total energy change is = heat + work

dU = dQ + dW

dU = 191 + 120

dU = 307 kJ

change in internal energy = 311 kJ

Therefore the change in internal energy of the system is 311 kJ