In a fuel cell (device used for producing electricity directly from a chemical reaction )methanol is used as a fuel and oxygen gas is used asan oxidizer. The standard enthalpyof combustion of methanol is -721kJ mol^(-1) . The standard free energiesof formation of CH_(3)OH(l, CO_(2)(g) andH_(2)O(l) are- 166.3 , -394.4 and - 237 .1 kJ mol^(-1) respectively. The standard internal energy change of the cell reaction will be

In a fuel cell (device used for producing electricity directly from a

1.	In a fuel cell (device used for producing electricity directly from a chemical reaction )methanol is used as a fuel and oxygen gas is used asan oxidizer. The standard enthalpyof combustion of methanol is -721kJ mol^(-1) . The standard free energiesof formation of CH_(3)OH(l, CO_(2)(g) andH_(2)O(l) are- 166.3 , -394.4 and - 237 .1 kJ mol^(-1) respectively. The standard internal energy change of the cell reaction will be
Answer» `-727.24 KJ mol^(-1)` `-724.76kJ mol^(-1)` `-728.48 kJ mol^(-1)` `- 723. 42 kJ mol^(-1)` SOLUTION :`DeltaU^(@) = DeltaH^(@) -Deltan_(G) RT` `= - 726 kJ mol^(-1) - (-(1)/(2))mol` `( 8.314 xx 10^(-3) kJ K^(-1) mol^(-1)) ( 298K)` `= - 726+ 1.24 kJ mol^(-1) = - 724 .76kJ mol^(-1)`