Question

A gas is compressed from an initial volume of 5.75L to a final volume of 1.24 L by an external pressure of 1.00 ATM. During the compression the gas releases 125 J of heat.  What is the change in internal energy of the gas?

Answer 1

Concepts and reason

The expansion or compression of gas can takes place in a reversible or in an irreversible manner based on the conditions used. An irreversible process may occur when internal pressure is greater than external pressure because, the system does not attain equilibrium at every stage of the process.

Fundamentals

Pressure-volume work:

Irreversible process: In this process, and the expansion of gas take place rapidly without maintaining equilibrium in the surroundings. Therefore, the pressure-volume work done against the constant external pressure is given below:

First law of thermodynamics:The first law of thermodynamics is defined as the change in internal energy of a system,which is equal to the heat supplied to the system added to the work done on the system.

Here

Given data:

Work done ‘W’ is calculated below:

Convert the units for work done from to.

Ans:

The internal energy change of the gas is.