How much has the internal energy of the gas changed, which did the work 75 J, while receiving the amount of heat 105 J.

Given:

Q1 = 75 Joules – the work done by the gas after receiving some energy;

Q2 = 105 Joules – the amount of heat (energy) that the gas received.

It is required to determine dQ (Joule) – how much the internal energy of the gas has changed.

To determine the change in the internal energy of a gas, you must use the following formula:

dQ = Q2 – Q1;

dQ = 105 – 75 = 30 Joules.

Answer: The internal energy of the gas has increased by 30 Joules.