Questions: Consider a hypothetical chemical reaction: A+B → C+D (In this equation A, B, C, and D stand for some unknown chemical formulas.) Here is an energy diagram for the reaction: Use the energy diagram to answer these questions. What is the heat of reaction? [1] kJ / mol Is the reaction exothermic or endothermic? Exothermic Endothermic Neither Can you determine the activation energy? Yes, it's [square] kJ / mol No. Can you determine the activation energy of the reverse reaction? C+D → A+B Yes, it's [square] kJ / mol No.

Consider a hypothetical chemical reaction:
A+B → C+D
(In this equation A, B, C, and D stand for some unknown chemical formulas.)
Here is an energy diagram for the reaction:

Use the energy diagram to answer these questions.
What is the heat of reaction? [1] kJ / mol
Is the reaction exothermic or endothermic? Exothermic Endothermic Neither
Can you determine the activation energy? Yes, it's [square] kJ / mol No.
Can you determine the activation energy of the reverse reaction? C+D → A+B Yes, it's [square] kJ / mol No.

Transcript text: Consider a hypothetical chemical reaction: \[ A+B \rightarrow C+D \] (In this equation $A, B, C$ and $D$ stand for some unknown chemical formulas.) Here is an energy diagram for the reaction: Use the energy diagram to answer these questions. \begin{tabular}{|c|c|} \hline What is the heat of reaction? & [1] $\mathrm{kJ} / \mathrm{mol}$ \\ \hline Is the reaction exothermic or endothermic? & Exothermic Endothermic Neither \\ \hline Can you determine the activation energy? & Yes, it's $\square$ $\mathrm{kJ} / \mathrm{mol}$ No. \\ \hline Can you determine the activation energy of the reverse reaction? \[ C+D \rightarrow A+B \] & Yes, it's $\square$ $\mathrm{kJ} / \mathrm{mol}$ No. \\ \hline \end{tabular}

Solution

Solution Steps

Step 1: Determine the heat of reaction

The heat of reaction is the difference between the energy of the products and the energy of the reactants. In this case, the energy of the products (C+D) is approximately 100 kJ/mol, and the energy of the reactants (A+B) is approximately 60 kJ/mol. Therefore, the heat of reaction is approximately $100 - 60 = 40$ kJ/mol.

Step 2: Determine if the reaction is exothermic or endothermic

Since the energy of the products is higher than the energy of the reactants, the reaction is endothermic. This means energy is absorbed during the reaction.

Step 3: Determine the activation energy

The activation energy is the difference between the energy of the transition state (the highest point on the curve) and the energy of the reactants. In this case, the energy of the transition state is approximately 250 kJ/mol, and the energy of the reactants is approximately 60 kJ/mol. Therefore, the activation energy is approximately $250 - 60 = 190$ kJ/mol.