In a certain process, the gas expanded and performed work of 400 J, while as a result of heat exchange it received 200 J.

In a certain process, the gas expanded and performed work of 400 J, while as a result of heat exchange it received 200 J. How and how much did the internal energy of the gas change?

To calculate the desired change in the internal energy of the taken gas, we apply the formula: Q = ΔU + A ‘(the first law of thermodynamics) and ΔU = Q – A’.

Variables: Q – energy received by gas (Q = 200 J); A ‘- work of the taken gas (A’ = 400 J).

Let’s calculate: ΔU = Q – A ‘= 200 – 400 = -200 J.

Answer: The change (decrease) in the internal energy of the taken gas is 200 J.