Question

Find the work done when 2 moles of hydrogen expand isothermally from 15 to 50 litres against a constant pressure of 1 atm at 25°C.

Options

• 847.0 cal

• 1436 kcal

• 84.7 cal

• 1436 cal

Answer 1

1436 cal

Explanation:

Here, n = 2, V₁ = 15 l, V₂ = 50 l

Temperature, T = 25° = 298 K

Pressure, P = 1 atm

For isothermal process, work done

w = – 2.303 nRT log `"V"_2/"V"_1`

w = – 2.303 × 2 × 2 × 298 log `50/15`

w = – 2745.18 log `50/15`

So, w = – 1435.39 cal ≈ – 1436 cal