Question

When producing hydrogen iodide, the energy of the reactants is 581 kJ/mol, and the energy of the products is 590 kJ/mol. The equation is shown.

H2 + I2 → 2HI

What is the total energy of the reaction? Is this an endothermic or exothermic reaction?

(1 point)
Responses

–9 kJ/mol, endothermic
–9 kJ/mol, endothermic

–9 kJ/mol, exothermic
–9 kJ/mol, exothermic

9 kJ/mol, endothermic
9 kJ/mol, endothermic

9 kJ/mol, exothermic
9 kJ/mol, exothermic

Answer 1

To determine the total energy change of the reaction, you can use the formula:

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

From the information given:

- Energy of the reactants (H₂ + I₂) = 581 kJ/mol
- Energy of the products (2HI) = 590 kJ/mol

Substituting these values in:

\[
\Delta H = 590 \, \text{kJ/mol} - 581 \, \text{kJ/mol} = 9 \, \text{kJ/mol}
\]

Since the value of \(\Delta H\) is positive (+9 kJ/mol), the reaction absorbs energy from the surroundings, indicating it is an endothermic reaction.

So the answer is:
**9 kJ/mol, endothermic.**