Q: The work of 146 kJ is performed in order to compress one kilo mole of a gas adiabatically and in this process the temperature of the gas increases by 7°C. The gas is (R = 8.3 J mol-1 K-1)
(a) Triatomic
(b) A mixture of monoatomic and diatomic
(c) Monoatomic
(d) Diatomic
Sol: (d) n = 103, W = – 146 × 103 J,
∆T = T2 – T1 = 7°C
$\large W = \frac{n R (T_2 -T_1)}{1 -\gamma} $
$\large -146 \times 10^3 = \frac{10^3 \times 8.3 \times 7 }{1 -\gamma} $
On solving , we get
γ = 1.4 (diatomic gas )