Exothermic and endothermic reactions

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Question 13
Medium

The reaction between hydrogen and fluorine is shown in the chemical equation below using displayed formulae:

H−H+F−F⟶2 H−F \text{H}-\text{H} + \text{F}-\text{F} \longrightarrow 2\ \text{H}-\text{F} H−H+F−F⟶2 H−F

The bond energies are given in the table below:

BondBond energy in kJ/mol\text{kJ/mol}kJ/mol
H−H\text{H}-\text{H}H−H436
F−F\text{F}-\text{F}F−F158
H−F\text{H}-\text{F}H−F562

Which expression shows how to calculate the overall energy change for this reaction?

436+158+562 kJ/mol436 + 158 + 562 \text{ kJ/mol}436+158+562 kJ/mol

436+158+(2×562) kJ/mol436 + 158 + (2 \times 562) \text{ kJ/mol}436+158+(2×562) kJ/mol

436+158−562 kJ/mol436 + 158 - 562 \text{ kJ/mol}436+158−562 kJ/mol

436+158−(2×562) kJ/mol436 + 158 - (2 \times 562) \text{ kJ/mol}436+158−(2×562) kJ/mol

Exothermic and endothermic reactions Questions

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