Question

3.3 energy changes in chemical reactions
in the following reaction, the bonds of the reactants break. how much energy does it take to break a single molecule of molecular oxygen (o₂)?
c₁₈h₃₇oh + 27o₂(g) → 18co₂(g) + 19h₂o(l)
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Explanation:

To determine the energy required to break a single molecule of \( O_2 \), we need to recall the bond dissociation energy of the \( O=O \) double bond in \( O_2 \). The standard bond dissociation energy for the \( O=O \) bond in \( O_2 \) is a known value from chemical data.

Step 1: Recall the bond dissociation energy of \( O_2 \)

The \( O_2 \) molecule has a double bond (\( O=O \)). The bond dissociation energy (the energy required to break one mole of \( O=O \) bonds) is approximately \( 498 \, \text{kJ/mol} \). This value is a standard value in chemical thermodynamics, representing the energy needed to break the \( O=O \) bond in one mole of \( O_2 \) molecules.

Answer:

The energy required to break a mole of \( O_2 \) (i.e., break the \( O=O \) bond in one mole of \( O_2 \) molecules) is \( \boldsymbol{498} \, \text{kJ/mol} \).