Calculate ΔG (in kJ/mol) of the reaction of molecular oxygen and carbon monoxide to produce carbon dioxide. The reaction occurs at 25°C. ΔH = -566 kJ/mol, ΔS = -173 J/K. Based on the result, determine the spontaneity of the reaction.
First we need to write down the chemical equation and balance it: O2 + 2CO -> 2CO2 Given the data, we can calculate ΔG using the following formula: ΔG = ΔH - TΔS However, before we plug in the numbers, we need to make sure that all data are given in correct units: We have to convert temperature into Kelvins: T = 25 + 273 = 298 K The entropy change (ΔS) is given in J/K, but the enthalpy change (ΔH) is given in kJ/mol. Therefore, we have to convert ΔH into J/mol or ΔS into kJ/K. Since the question is asking for ΔG in kJ/mol, it would be sensible to convert ΔS into kJ/K: ΔS = -0.173 kJ/mol Now we can use the formula to calculate ΔG: ΔG = ΔH - TΔSΔG = -566 - 298*(-0.173) ΔG = -514 kJ/mol Given that ΔG is negative, the reaction is exergonic, that is it occurs spontaneously at 25°C.
