Answer to Question #100171 in Physical Chemistry for anon

Question

the standard enthalpy of combustion of ethane, carbon, and hydrogen are -1559.7 kJ/mol, -393kJ/mol and -286kJ/mol respectively.
Use Hess'ss law to find the enthalpy of formation of ethane

Answer 1

ΔH_form(C₂H₆)=ΔH_comb(C₂H₆)-(2ΔH_comb(C)+3ΔH_comb(H₂))=-1559.7-(2(-393)+3(-286))=84,3 kJ/mol