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deltaH Units

Posted: Wed Jan 24, 2018 6:50 pm
by Clarisse Wikstrom 1H
When putting our final answer, how do we know whether the units for deltaH are kJ or kJ/mol? I've seen both so I was wondering if we would get marked off on the test if we wrote the wrong one. Thanks!

Re: deltaH Units

Posted: Wed Jan 24, 2018 7:46 pm
by Sophie Krylova 2J
Usually you would give the answer in the same units as the data given.

Re: deltaH Units

Posted: Wed Jan 24, 2018 7:48 pm
by Deap Bhandal L1 S1J
An example would be the delta H of a reaction is in kJ. However delta H formation could be written in kJ/mole of the product if we divide the original number by the molar coefficient of the product. The kJ/mole is specific for a substance and if you know the amount of moles of the substance you can convert between the two.

Re: deltaH Units

Posted: Fri Jan 26, 2018 1:04 am
by CalebBurns3L
You have to write out the units for each step of the reaction so you know what units your final answer should be in.

Re: deltaH Units

Posted: Fri Jan 26, 2018 11:02 am
by Jimmy Zhang Dis 1K
I believe that standard delta H and delta H of a reaction are in KJ while delta H of formation is in KJ/mol

Re: deltaH Units

Posted: Fri Jan 26, 2018 1:02 pm
by Chris Lamb 1G
I was under the impression that when calculating the standard reaction enthalpy, we use kJ/mol. For just regular reaction enthalpy, I would put kJ. But I would like to know if that is true or not.