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Which of the following equations represents an enthalpy of combustion? A 2CH₄(g) + 3O₂(g) → 2CO₂(g) + 4H₂O(l) B CH₄(g) + 1O₂(g) → CO(g) + 2H₂O(l) C 2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l) D C₃H₈(g) + 3O₂(g) → 2CO₂(g) + 3H₂O(l) - Scottish Highers Chemistry - Question 12 - 2023
Question 12
Which of the following equations represents an enthalpy of combustion? A 2CH₄(g) + 3O₂(g) → 2CO₂(g) + 4H₂O(l) B CH₄(g) + 1O₂(g) → CO(g) + 2H₂O(l) C 2C₂H₆(g) + ... show full transcript
Worked Solution & Example Answer:Which of the following equations represents an enthalpy of combustion? A 2CH₄(g) + 3O₂(g) → 2CO₂(g) + 4H₂O(l) B CH₄(g) + 1O₂(g) → CO(g) + 2H₂O(l) C 2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l) D C₃H₈(g) + 3O₂(g) → 2CO₂(g) + 3H₂O(l) - Scottish Highers Chemistry - Question 12 - 2023
Step 1
D C₃H₈(g) + 3O₂(g) → 2CO₂(g) + 3H₂O(l)
Answer
To determine which equation represents an enthalpy of combustion, we need to identify the reaction where a hydrocarbon reacts with oxygen to produce carbon dioxide and water.
- In equation D, propane (C₃H₈) reacts with oxygen (O₂) to form carbon dioxide (CO₂) and water (H₂O). This is characteristic of a combustion reaction.
- Equations A, B, and C either do not fully combust a hydrocarbon or produce carbon monoxide (CO) instead of carbon dioxide.
Thus, the correct answer is:
D C₃H₈(g) + 3O₂(g) → 2CO₂(g) + 3H₂O(l), representing the enthalpy of combustion.