Question

A gas is compressed from 600 cm3 to 200 cm3 at a constant pressure of 400 kPa. At the same time, 100 J of heat energy is transferred out of the gas. What is the change in thermal energy of the gas during this process?

Short answer

The value of Thermal energy is 60J

Step-by-step solution

Definition of first law of thermodynamics

First law of thermodynamics define the energy does not create or destroy in the universe

Finding the value of thermal energy 

As $E_{thi}=W+Q$

role="math" localid="1649081639395" $W=-p∆V$

Now

role="math" localid="1649081525941" $\begin{array}{rcl}∆V& =& V_f-V_i\\ & =& \left(200-600\right)c{m}^3\end{array}$

Now $∆V$ is converted from cm to m $-4\times {10}^{-4}{m}^3$

applying all values

$\begin{array}{rcl}W& =& -p∆V\\ & =& (400\times {10}^{3}Pa)(-4\times {10}^{-4}{m}^3)\\ & =& -160J\end{array}$

So, the thermal energy is

$\begin{array}{rcl}∆E_{thi}& =& -w+Q\\ & =& \left(160-100\right)J\\ & =& 60J\end{array}$