Question

Standard enthalpy of formation of ethane, C₂H_6(g) is -84.7 kJ mol^-1.Calculate the enthalpy change for the formation of 0.1 kg ethane.

Answer 1

Given : 

Enthalpy of formation of C₂H_6(g)

= Δ_fH⁰ = ΔH₁ = -84.7 kJ mol 

Mass of C₂H₆ = 0.1 kg = 100 g 

Molar mass of C₂H₆ = 30 g mol^-1

ΔH⁰ for the formation of 0.1 kg C₂H₆  = 100 g 

C₂H₆  = ΔH₂ = ?

∴ Heat of formation = -282.3 kJ