Alculate the standard enthalpy of formation of ethanoic acid given that the standard enthalpy of combustion for carbon is –394 kj mol-1 , hydrogen is –286 kj mol-1 and ethanoic acid is –876 kj mol-

The standard enthalpy of formation of ethanoic acid is -484 kJ/mol.

Explanation:

...[1]

..[2]

..[3]

The standard enthalpy of formation of ethanoic acid :

..[4]

Using Hess's law to calculate :

2 × [1] + 2 × [2] - [3] = [4]

The standard enthalpy of formation of ethanoic acid is -484 kJ/mol.

since electrons are negative the answer is neagtaive