Determine the constant external pressure required to compress 2 mole of an ideal gas from volume 10.8\ dm^3 to 5.4\ dm^3 if the work obtained is 2460 J.

Question

Quantrex Academy · Accepted Answer

Correct answer: D. 4.56 bar

Work done during compression against a constant external pressure is

W = -P_{\text{ext}} \Delta V

.

Given

W = 2460 \text{ J}

,

V_1 = 10.8 \text{ dm}^3

,

V_2 = 5.4 \text{ dm}^3

.

\Delta V = 5.4 - 10.8 = -5.4 \text{ dm}^3 = -5.4 \text{ L}

.

Substituting the values:

2460 \text{ J} = -P_{\text{ext}} \times (-5.4 \text{ L})

Since

1 \text{ L bar} = 100 \text{ J}

, we have:

2460 = P_{\text{ext}} \times 5.4 \times 100

P_{\text{ext}} = \dfrac{2460}{540} = 4.555 \text{ bar} \approx 4.56 \text{ bar}

.

Answer:

4.56

bar

Determine the constant external pressure required to compress 2...

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