Question

calculate the heat of reaction δh for the following reaction: 2hcl(g) + f₂(g)→2hf(g) + cl₂(g) you can find a table of bond energies by using the data button on the aleks toolbar. round your answer to the nearest kj/mol.
□ \frac{kj}{mol}

Explanation:

Step1: Recall Bond Energy Formula

The enthalpy change of a reaction ($\Delta H$) using bond energies is calculated as:
$\Delta H = \sum (\text{Bond energies of reactants broken}) - \sum (\text{Bond energies of products formed})$

Step2: Identify Bonds Broken/Formed

• Reactants: $2\,\text{HCl}(g)$ (2 H-Cl bonds) and $1\,\text{F}_2(g)$ (1 F-F bond).
• Products: $2\,\text{HF}(g)$ (2 H-F bonds) and $1\,\text{Cl}_2(g)$ (1 Cl-Cl bond).

Step3: Look Up Bond Energies

From bond energy tables:

• $D(\text{H-Cl}) = 431\,\text{kJ/mol}$
• $D(\text{F-F}) = 159\,\text{kJ/mol}$
• $D(\text{H-F}) = 565\,\text{kJ/mol}$
• $D(\text{Cl-Cl}) = 242\,\text{kJ/mol}$

Step4: Calculate Energy for Reactants

Energy to break bonds:
$2 \times D(\text{H-Cl}) + D(\text{F-F}) = 2(431) + 159 = 862 + 159 = 1021\,\text{kJ/mol}$

Step5: Calculate Energy for Products

Energy released to form bonds:
$2 \times D(\text{H-F}) + D(\text{Cl-Cl}) = 2(565) + 242 = 1130 + 242 = 1372\,\text{kJ/mol}$

Step6: Compute $\Delta H$

$\Delta H = 1021 - 1372 = -351\,\text{kJ/mol}$

Answer:

$\boxed{-351}$