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units for enthalpies

Posted: Mon Jan 15, 2018 3:20 pm
by mayasinha1B
I've noticed that sometimes enthalpies are used in units of kJ and sometimes in kJ/mol. How do we know which is right to use when? I assumed that it was when an enthalpy is multiplied by a certain number of moles for a particular reaction but on problem 8.67 part b when it multiplies kJ/mol with moles the ending unit is still kJ/mol and I was confused. C

Re: units for enthalpies

Posted: Mon Jan 15, 2018 3:31 pm
by sahiltelang-Discussion 1J
Based on the problem we can find out what they are asking. If it asks how much energy for a certain amount of reactants in a given equation then provide kJ, but on the other hand when they ask for the heat of formation then provide it as kJ/mol. For the problem you mentioned it asks for a standardized value based off the formation of certain products. Thus a standardized value would denote having the per mole to the units.