Question

The internal energy change (in J) when 90 g of water undergoes complete evaporation at 100°C is ...............

(Given : ΔH_vap for water at 373 K = 41 kJ/mol, R = 8.314 JK^–1 mol^–1)

Numerical Value Type

Comments

Thermodynamics, Enthalpy Change of a Reaction

Answer 1

Ans. (189494)

Sol. ΔH = ΔU + ΔngRT

41000 × 5 = ΔU + 5 × 8.314 × 373

205000 = ΔU + 15505.61

ΔU = 189494.39 J = 189494 J