Question

Calculate the change in enthalpy (LaTeX: \DeltaΔH) of a reaction with the following information:

Answer 1

Answer: -19 kJ

Explanation:

The change in enthalpy $\Delta H$ is mathematically expressed as the difference between the the total potential energy of products $U_{products}$ and the potential energy of the reactants $U_{reactants}$:

$\Delta H=U_{products}-U_{reactants}$

Where:

$U_{products}=110 kJ=110 (10)^{3}J$

$U_{reactants}=129 kJ=129 (10)^{3}J$

Then:

$\Delta H=110 kJ-129 kJ$

$\Delta H=-19 kJ$ The negative sign in this result means we have a negative enthalpy, hence an exothermic reaction (where heat is released).