Question

7. Calculate the constant external pressure required to
compress 5 moles of an ideal gas from
23x10 m to 8x10 m in doing 4.545 kJ of
work.
(2 m)​

Answer 1

The  constant external pressure required to compress 5 moles of an ideal gas is equal to 15.15 Pa.

• The work done in compressing an ideal gas is equal to ∫P.dV .
• Since pressure is constant the integral evaluates to P×ΔV.
• Now equating W=PΔV, we get

                              ⇒P=W/ΔV

                              ⇒P=4545/(2×10×(23-8))

                              ⇒P=4545/300 ⇒P=15.15 Pa

• Hence constant external pressure applied to the gas must be 15.15 Pa.