The enthalpy change (\( \Delta H \)) of a reaction can be calculated using the formula:
\[ \Delta H = H_{\text{products}} - H_{\text{reactants}} \]
In your case:
- Enthalpy of reactants (\( H_{\text{reactants}} \)) = 100
- Enthalpy of products (\( H_{\text{products}} \)) = 300
So, substituting these values into the formula, we get:
\[ \Delta H = 300 - 100 = 200 \]
The enthalpy change of the reaction is \( 200 \) (units will depend on the measurement, typically kJ/mol).
This indicates that the reaction is endothermic, as the enthalpy of the products is greater than that of the reactants. On an energy profile graph, this would be represented by an increase in energy from the reactants to the products.