Question

Consider a system consisting of one mole of an ideal diatomic gas in a container with piston. What is the temperature change of the gas, if q = 50.0 J and W = -100.0 J?

• A. $-50J$
• B. $-2.4J$
• C. $-5.8J$
• D. $-1.25J$

Answer 1

The correct option is B $-2.4J$

According to first law of thermodynamics,
$△E=q+W$
$=50-100=-50J$
Molar heat capacity at constant volume, $C_V={\left(\frac{△E}{△T}\right)}_V$
$\therefore △T=\frac{△E}{C_V}=\frac{-50J}{\frac{5}{2}R}$
$=\frac{-50}{\frac{5}{2}\times 8.314}=-2.41K$