Question

Figure A shows the variation of pressure (in atm) with volume (in L) for one [3] mole of an ideal gas. Calculate the heat (QAR) and work done from state A to state B in joules (WA) if change in internal energy (AUsa) is 50 cal.

Answer 1

We know that

Thermodynamics first law

$dQ=dU+PdV$

$dQ=50\times4.2+1\times RT$

$dQ=50\times4.2+1\times 8.31T$

$dQ=210+ RT$

Work

$W=PdV$

PdV=nRT

$W=PdV=RT=8.31T J$