Question

What is constant external pressure required to compress 2 moles of an ideal gas from 25 $dm^3$ to 13 $dm^3$ when the work obtained is 48.6 $dm^3$ bar?

• A. 4.05 bar
• B. 7.13 bar
• C. 8.33 bar
• D. 10.12 bar

Answer 1

Answer: (A)

4.05 bar

Answer 2

The work done on the gas (given as 48.6 $dm^3 \cdot bar$) for a constant external pressure during compression is given by:

$W = P_{ext} \times (V_1 - V_2)$

Calculate the change in volume:

$\Delta V = V_1 - V_2 = 25 \, dm^3 - 13 \, dm^3 = 12 \, dm^3$

Solve for the pressure:

$P_{ext} = \frac{W}{\Delta V} = \frac{48.6 \, dm^3 \cdot bar}{12 \, dm^3} = 4.05 \, bar$