Laws Of Thermodynamics

Step 1: Writing the Combustion Reactions The combustion reactions are:

C%20(graphite)%20%2B%20O_2%20%5Crightarrow%20CO_2%20%5Cquad%20%5CDelta%20H%20%3D%20-393%20%5Ctext%7B%20kJ%20mol%7D%5E%7B-1%7D

H_2%20%2B%20%5Cfrac%7B1%7D%7B2%7DO_2%20%5Crightarrow%20H_2O%20%5Cquad%20%5CDelta%20H%20%3D%20-286%20%5Ctext%7B%20kJ%20mol%7D%5E%7B-1%7D

CH_3OH%20%2B%20%5Cfrac%7B3%7D%7B2%7D%20O_2%20%5Crightarrow%20CO_2%20%2B%202H_2O%20%5Cquad%20%5CDelta%20H%20%3D%20-726%20%5Ctext%7B%20kJ%20mol%7D%5E%7B-1%7D

Step 2: Applying Hessâ€™s Law

%5CDelta%20H_f%20%5Ctext%7B(CH%7D_3%5Ctext%7BOH)%7D%20%3D%20%5CDelta%20H_%7B%5Ctext%7Bcombustion%7D%7D(%5Ctext%7BCH%7D_3%5Ctext%7BOH%7D)%20-%20%5Cleft%5B%20%5CDelta%20H_%7B%5Ctext%7Bcombustion%7D%7D(C)%20%2B%202%20%5Ctimes%20%5CDelta%20H_%7B%5Ctext%7Bcombustion%7D%7D(H_2)%20%5Cright%5D

%3D%20-726%20-%20%5Cleft%5B%20-393%20%2B%202(-286)%20%5Cright%5D

%3D%20-726%20%2B%20393%20%2B%20572

%3D%20-239%20%5Ctext%7B%20kJ%20mol%7D%5E%7B-1%7D

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Chapter Questions
1 MCQs