Work

Help Questions

Physical Chemistry › Work

Questions 1 - 2

1

Argon gas is confined in a $3.0 \textup{ m}^3$ container at $310 \textup{ K}$ . What is the work done if the gas expands against an external pressure of $5.1 \textup{ kPa}$ to a volume of $3.5 \textup{ m}^3$ ? $1.0\textup{ Pa}\cdot \textup{m}^{3}=1.0 \textup{ J}$

$-2550\textup{ J}$

$-17847\textup{ J}$

$0.5\textup{ J}$

$-5100\textup{ J}$

$-1250\textup{ J}$

Explanation

The work () done by a system is:

$W=-p_{ex}\bigtriangleup V$

$\Delta V=V_{f}-V_{i}$ with $V_{f}=final\ volume$ and $V_{i}=initial\ volume$

Plugging the values given into the work equation gives:

$W=-(5.1\times 10^{3}\ Pa)\times(3.5-3.0)m^{3}=-2550\ J$

2

Argon gas is confined in a $1.4\textup{ m}^3$ at $270 \textup{ K}$ . What is the work done if the gas expands against an external pressure of $3.2 \textup{ kPa}$ to a volume of $2.0 \textup{ m}^3$ ?

$1.0\textup{ Pa}\cdot \textup{m}^{3}=1.0 \textup{ J}$

$-1920\textup{ J}$

$10.1\textup{ J}$

$201.1\textup{ J}$

$53.8\textup{ J}$

$61\textup{ J}$

Explanation

The work () done by a system is:

$W=-p_{ex}\bigtriangleup V$

$\Delta V=V_{f}-V_{i}$ with $V_{f}=final\ volume$ and $V_{i}=initial\ volume$

Plugging the values given into the work equation gives:

$W=-(3.2\times 10^{3}\ Pa)\times(2.0-1.4)m^{3}=-1920\ J$

Return to subject