2.2 g of nitrous oxide (N2O) gas is cooled at a constant pressure of 1 atm from 310 K to 270 K causing the compression of the gas from 217.1 mL to 167.75 mL. The change in internal energy of the process, $\Delta$U is '$-$x' J. The value of 'x' is ________. [nearest integer]
(Given : atomic mass of N = 14 g mol$-$1 and of O = 16 g mol$-$1. Molar heat capacity of N2O is 100 J K$-$1 mol$-$1)
Answer (integer)
195
Solution
$\Delta T=-40 \mathrm{~K}$
<br/><br/>
$$
\begin{aligned}
\Delta U &=q+w \\\\
&=\frac{100 \times 2.2}{44}(-40)-(-49.39) \times 10^{-3} \times 101.325
\end{aligned}
$$
<br/><br/>
$$
\begin{aligned}
&=-200+5 \\\\
&=-195 \mathrm{~J} \\\\
\mathrm{x}=& 195
\end{aligned}
$$
About this question
Subject: Chemistry · Chapter: Thermodynamics · Topic: Zeroth and First Law
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