Unit Confusion

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Unit Confusion

Postby jeffreyli1L » Thu Jan 19, 2017 7:35 pm

I have a short question about units with these problems concerning the enthalpy of different reactions.
Do we use kJ/mol to describe the number of kJ transferred when 1 mol of a chemical is reacted? Or should we use just kJ to describe the number of kJ transferred when the reaction occurs as it is written (because the stoichiometric coefficients in the equations do not necessarily equal 1). Thank you!

Andrew Nguyen 3G
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Joined: Wed Sep 21, 2016 2:59 pm

Re: Unit Confusion

Postby Andrew Nguyen 3G » Thu Jan 19, 2017 10:42 pm

For reaction enthalpy, we use kJ only without the /mol. That is because when a reaction proceeds, a certain amount of heat is released or absorbed by the system, which is directly related to the coefficients in the reactants and products anyway. And because the given enthalpy is tied to the coefficients of the reaction equation itself, it would be misleading to use kJ/mol, even if the coefficients were all 1.

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