Problem: From the enthalpies of reaction2 C(s) + O2(g) → 2CO(g)                               ΔH = -221.0 kJ2C(s) + O2(g) + 4H2(g) → 2CH3OH(g)       ΔH = -402.4 kJcalculate ΔH for the reaction:CH3OH(g) → CO(g) + 2H2(g) a) -90.7 kJ      b) 90.7 kJ       c) -623.4 kJ    d) 180.7 kJ     e) 623.4 kJ

FREE Expert Solution

Apply Hess’s Law to determine the ΔH of the overall reaction where we have to get the sum of ΔH of the elementary reactions given

  • The overall reaction appears to be:

CH3OH (g)  CO (g) + 2H2 (g) 

  • And the elementary reactions are:

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

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Problem Details

From the enthalpies of reaction

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

calculate ΔH for the reaction:

CH3OH(g) → CO(g) + 2H2(g) 

a) -90.7 kJ      

b) 90.7 kJ       

c) -623.4 kJ    

d) 180.7 kJ     

e) 623.4 kJ

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