Question

Five moles of Hydrogen initially at STP compressed acrobatically so that its temperature becomes 73K. The increase in internal of the gas in Kilo joules is:
$(R-8.3j/mole-K:\gamma =1.4fordiatomicgas)$

• A. 80.5
• B. 21.55
• C. 41.5
• D. 65.55

Answer 1

The correct option is C 41.5

Given that,

$R=8.314J/mole$

$\gamma =1.4$

$T_1=673K$

$T_2=273K$

Change in internal energy in adiabatic process is

$\Delta U=\frac{nR}{\gamma -1}(T_1-T_2)$

$=\frac{5\times 8.3}{0.4}(673-273)$

$=\frac{5\times 8.3\times 400}{0.4}$

$=41.5KJ$