Question

The total bonding energy for the products of a reaction is 2535 kJ/mol and the bonding energy of the reactants is 1375 kJ/mol. Calculate the change in enthalpy, and classify the reaction as endothermic or exothermic.
-1160 kJ/mol, endothermic

1160 kJ/mol, exothermic

-1160 kJ/mol, exothermic

1160 kJ/mol, endothermic

Answer 1

Answer:

1160 kJ/mol, endothermic

Explanation:

The change in enthalpy is calculated as follows:

ΔH of reaction = H of products - H of reactants

Then, for this case:

ΔH of reaction = 2535 - 1375 = 1160 kJ/mol

• Endothermic reactions have a positive change in enthalpy
• Exothermic reactions have a negative change in enthalpy

Answer 2

Exothermic reactions release heat so is in negative and endothermic is vice versa