Question

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Answer 1

Answer:

$\large \boxed{\text{-1276 kJ/mol}}$

Explanation:

You calculate the energy required to break all the bonds in the reactants.

Then you subtract the energy needed to break all the bonds in the products.

                             CH₃CH₂OH        +  3O₂ ⟶ 2CO₂ + 3H₂O

Bonds:         5C-H 1C-C 1C-O 1O-H    3O=O     4C=O   6O-H

D/kJ·mol⁻¹:    413    347  358  467       495        799      467

$\Delta H = \sum{D_{\text{reactants}}} - \sum{D_{\text{products}}}\\\sum{D_{\text{reactants}}} = 5 \times 413 + 1 \times 347 + 1 \times 358 + 1 \times 467 + 3 \times 495 = 3237 + 1485\\=\text{4722 kJ}\\\sum{D_{\text{products}}} = 4 \times 799 + 6 \times 467 =3196 + 2802 = \text{5998 kJ}\\\Delta H = 4722 - 5998= \textbf{-1276 kJ} \\ \text{The overall energy change is \large \boxed{\textbf{-1276 kJ/mol}} }.$