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8. Methanol (CH₃OH) is an important chemical in industry - Scottish Highers Chemistry - Question 8 - 2016
Question 8
8. Methanol (CH₃OH) is an important chemical in industry. (a) Methanol is produced from methane in a two-step process. In step 1, methane is reacted with steam as s... show full transcript
Worked Solution & Example Answer:8. Methanol (CH₃OH) is an important chemical in industry - Scottish Highers Chemistry - Question 8 - 2016
Step 1
Step 2
Step 3
The atom economy of this reaction is 100%. Explain what this means.
Answer
An atom economy of 100% indicates that all atoms from the reactants are converted into the desired product. This means there are no by-products or waste products generated in the reaction, ensuring maximum efficiency in using the original materials.
Step 4
Using bond enthalpy and mean bond enthalpy values from the data booklet, calculate the enthalpy change, in kJ mol⁻¹, for the reaction.
Answer
To calculate the enrthalpy change for the reaction, we can use the bond enthalpy values:
Breaking bonds:
- 412 (C-H) x 4 = 1648 kJ
- 360 (C-O) = 360 kJ
- 463 (O-H) x 2 = 926 kJ
Total bond breaking = 1648 + 360 + 926 = 2934 kJ
Forming bonds:
- 743 (C=O) = 743 kJ
- 412 (C-H) x 2 = 824 kJ
- 463 (O-H) x 2 = 926 kJ
Total bond forming = 743 + 824 + 926 = 2493 kJ
Enthalpy change (ΔH) = Total bond breaking - Total bond forming ΔH = 2934 - 2493 = 441 kJ
Thus, the enthalpy change for this reaction is 441 kJ mol⁻¹.