kJ vs. kJ/mol

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Rucha Kulkarni 2A
Posts: 43
Joined: Fri Sep 29, 2017 7:05 am

kJ vs. kJ/mol

Postby Rucha Kulkarni 2A » Sun Jan 14, 2018 8:04 pm

When do we use kJ/mol for enthalpy? Is kJ only when moles aren't specified or whenever you're calculating the overall reaction enthalpy?

Krupa Prajapati
Posts: 50
Joined: Sat Jul 22, 2017 3:00 am

Re: kJ vs. kJ/mol

Postby Krupa Prajapati » Sun Jan 14, 2018 8:09 pm

Hi Rucha,

We use KJ/mole usually when we want to know the enthalpy of formation for a certain molecule. However, when we are finding the change in enthalpy for an overall reaction we only use KJ because we are not finding the change for any molecule in particular, so we cannot use KJ/mole. Hope this helps!

Peri Bingham 1G
Posts: 50
Joined: Fri Sep 29, 2017 7:03 am

Re: kJ vs. kJ/mol

Postby Peri Bingham 1G » Sun Jan 14, 2018 9:14 pm

For the standard enthalpy of formation, the units are always kJ/mol.

Nathan Tu 2C
Posts: 46
Joined: Fri Sep 29, 2017 7:07 am

Re: kJ vs. kJ/mol

Postby Nathan Tu 2C » Sun Jan 14, 2018 9:22 pm

We describe enthalpy in terms kj. When we talk about a reaction, the kj/reaction is implied. When we talk about kj/mol, we are referring to kj per mole of that substance.

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