Question

What is the amount of work done when 0.5 mole of methane, CH₄ (g), is subjected to combustion at 300 K? (Given, R = 8.314 JK^-1mol^-1)

Options

• - 2494 J

• - 4988 J

• + 4988 J

• + 2494 J

Answer 1

+ 2494 J

Explanation:

$$0.5\mathrm{CH}{\phantom{A}}_4(\mathrm{g})+\mathrm{O}{\phantom{A}}_2(\mathrm{g})⟶0.5\mathrm{CO}{\phantom{A}}_2(\mathrm{g})+\mathrm{H}{\phantom{A}}_2\mathrm{O}(\mathrm{l})$$

Δn = 0.5 - 1.5 = - 1

Work done

= - ΔnRT = - (- 1) × 8.314 × 300 = 2494 J