Question

When 2 moles of an ideal gas are expanded isothermally from a volume of 12.5 L to 15.0 L against constant external pressure of 7 60 mm Hg. Calculate the amount of work done in joule?

Options

• - 1924.0 J

• - 25.325 J

• - 253.25 J

• - 190.0 J

Answer 1

- 253.25 J

Explanation:

n = 2 mol, V₁ = 12.5 L = 12.5 × 10^-3 m³, V₂ = 15.0 L = 15.0 × 10^-3 m³,

P = 760 mm of Hg = 1.013 × 10⁵ Nm^-2

W = - P_ext (V₂ - V₁)

= - 1.013 × 10⁵ (15.0 - 12.5)10^-3

= - 2.5325 × 105 × 10^-3

∴ W = - 253.25 J