Problem: You may want to reference (Pages 184 - 186) Section 5.6 while completing this problem.From the enthalpies of reaction2 C(s) + O2(g) → 2 CO(g), ΔH = -221.0 kJ2 C(s) + O2(g) + 4 H2 (g) → 2 CH3OH(g), ΔH = -402.4 kJCalculate H for the reactionCO (g) + 2H2 (g)  →  CH3OH (g)

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2 C(s) + O2(g) → 2 CO(g), ΔH = -221.0 kJ
2 C(s) + O2(g) + 4 H2 (g) → 2 CH3OH(g), ΔH = -402.4 kJ


CO (g) + 2 H2 (g)  →  CH3OH(g)


We now need to find a combination of reactions that when added up, gives us the overall reaction.

For (1): CO(g) is on the opposite side. To correct this, we need to reverse the reaction. Reversing a reaction changes the sign of ΔH. To get the correct coefficient, we can divide this reaction by 2.

Current reaction sequence:

CO(g) → C(s) + 1/2 O2(g)            ΔH1 = (+221.0 kJ) ÷ 2 = +110.5 kJ


For (2): We can see that CH3OH is on the same side as the overall reaction. To get the correct coefficient, we can divide this reaction by 2.

Current reaction sequence:

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Problem Details

You may want to reference (Pages 184 - 186) Section 5.6 while completing this problem.


From the enthalpies of reaction

2 C(s) + O2(g) → 2 CO(g), ΔH = -221.0 kJ
2 C(s) + O2(g) + 4 H2 (g) → 2 CH3OH(g), ΔH = -402.4 kJ


Calculate H for the reaction

CO (g) + 2H2 (g)  →  CH3OH (g)


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