Question

The standard enthalpies of combustion of fumaric acid and maleic acid (to form carbon dioxide and water) are - 1336.0 kJ moJ-1 and - 1359.2 kJ moJ-1, respectively. Calculate the enthalpy of the following isomerization process:

maleic acid ----> fumaric acid

Answer 1

The enthalpy change for the isomerization process of maleic acid to fumaric acid is 23.2 kJ/mol.

Step-by-step explanation:

The enthalpy change for the isomerization process of maleic acid to fumaric acid can be calculated using the standard enthalpies of combustion of the two acids. The enthalpy change is given by the difference in the standard enthalpies of combustion of the reactants and products:

ΔH = ΔHfumaric acid - ΔHmaleic acid

Substituting their respective values, the enthalpy change for the isomerization process is:

ΔH = -1336.0 kJ/mol - (-1359.2 kJ/mol) = 23.2 kJ/mol

Answer 2

Step-by-step explanation:

maleic acid ⇒ fumaric acid

ΔHreaction = ΔHproduct - ΔHreactant

ΔHproduct = -1336.0 kJ mol⁻¹

ΔHreactant = - 1359.2 kJ mol⁻¹.

ΔHreaction = -1336.0 kJ mol⁻¹ - ( - 1359.2 kJ mol⁻¹.)

= 1359.2 kJ mol⁻¹ -1336.0 kJ mol⁻¹

= 23.2 kJ mol⁻¹ .

Enthalpy of isomerization from maleic to fumaric acid is 23.2 kJ per mol.