1.Given the reactant is 100KJ/mol and product is 300KJ/mol. Calculate the enthalpy change of the energy profile graph?

2. What does the answer in (1) indicate?. Explain.

1 answer

To calculate the enthalpy change (∆H) of the reaction, we use the formula:

\[ \Delta H = \text{Enthalpy of products} - \text{Enthalpy of reactants} \]

  1. Given:
    • Enthalpy of reactants = 100 kJ/mol
    • Enthalpy of products = 300 kJ/mol

Plugging these values into the formula:

\[ \Delta H = 300 \text{ kJ/mol} - 100 \text{ kJ/mol} = 200 \text{ kJ/mol} \]

So, the enthalpy change (\( \Delta H \)) is +200 kJ/mol.

  1. This positive enthalpy change indicates that the reaction is endothermic. In an endothermic reaction, energy is absorbed from the surroundings, which often results in a decrease in temperature of the surroundings (assuming no other heat sources are present). The products of the reaction have higher energy than the reactants, which is represented by the positive sign of the enthalpy change. In summary, the reaction requires energy input to proceed, and this is reflected in the energy profile graph, where the products are at a higher energy level compared to the reactants.