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Suggest why a mixture of methane and oxygen does not react at room temperature - AQA - GCSE Chemistry Combined Science - Question 7 - 2021 - Paper 1
Question 7
Suggest why a mixture of methane and oxygen does not react at room temperature. Answer in terms of particles. - - - - - - - - - - - - - - - - - - - - - - - - - - -... show full transcript
Worked Solution & Example Answer:Suggest why a mixture of methane and oxygen does not react at room temperature - AQA - GCSE Chemistry Combined Science - Question 7 - 2021 - Paper 1
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07.3 Calculate the C–C bond energy (X).
Answer
To calculate the C–C bond energy (X), we first determine the energy associated with bonds broken and bonds formed:
- Bonds broken:
- 8 (H–C) bonds: 8 × 410 = 3280 kJ
- 2 (C–C) bonds: 2 × X = 2X kJ
- 5 (C=O) bonds: 5 × 500 = 2500 kJ
Total energy for bonds broken = 3280 + 2X + 2500 = 5780 + 2X kJ
- Bonds formed:
- 6 (O–H) bonds: 6 × 460 = 2760 kJ
Total energy for bonds formed = 8120 kJ
The net energy released is given by:
Energy released = Energy of bonds broken - Energy of bonds formed
Substituting the values:
5780 + 2X - 8120 = -1640
Rearranging gives:
2X = 700 X = 350 kJ/mol
Therefore, the C–C bond energy (X) is 350 kJ/mol.