Question

Use bond energies to calculate ΔHrxn for the reaction.

2H₂(g)+O₂(g)→2H₂O(g)

Answer 1

To calculate the enthalpy change (ΔHrxn) for the given reaction, you can use bond energies. By considering the bonds broken and formed, you can calculate ΔHrxn using the formula: ΔHrxn = Σ (bonds broken) - Σ (bonds formed). In this case, you would calculate ΔHrxn as (2 * 105 kcal/mol) + (1 * 119 kcal/mol) - (4 * 110 kcal/mol).

Step-by-step explanation:

When calculating the enthalpy change (ΔHrxn) for a reaction using bond energies, you need to consider the bonds that are broken and formed. In this reaction, 2 H-H bonds (105 kcal/mol) and 1 O=O bond (119 kcal/mol) are broken, while 4 O-H bonds (110 kcal/mol) are formed. The energy changes can be tabulated and calculated using the formula: ΔHrxn = Σ (bonds broken) - Σ (bonds formed). Plugging in the values, we get: ΔHrxn = (2 * 105 kcal/mol) + (1 * 119 kcal/mol) - (4 * 110 kcal/mol).