### kg or g

Posted:

**Mon Oct 22, 2018 1:04 am**Which equations in quantum use kg and which ones use grams?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=14&t=34544

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Posted: **Mon Oct 22, 2018 1:04 am**

Which equations in quantum use kg and which ones use grams?

Posted: **Mon Oct 22, 2018 1:16 am**

I would assume that most quantum equations, if not all, use kg because kg is the SI unit for mass. Looking at the equation sheet from our last test, it seems that all the equations will involve kg. If the given is in grams, then you would change it to kg before solving the problem. Hope this helps!

Posted: **Mon Oct 22, 2018 8:00 am**

kg since that is what our SI units tell us (convert grams to 10^-3 kg)

Posted: **Mon Oct 22, 2018 9:26 am**

kg is the SI unit. Grams is only used for moles. Also Joules is kg m^2 s^-2, so it would make sense to use kg.

Posted: **Mon Oct 22, 2018 2:20 pm**

Kg is used because it is the SI unit.

Posted: **Mon Oct 22, 2018 3:12 pm**

everything uses kg, molar mass is given in g per mole however for simplicity purposes and to make it easier to write out.

Posted: **Wed Oct 24, 2018 10:26 am**

well everything uses kg even though molar mass is given in g per mole. it makes it easier to write out

Posted: **Wed Oct 24, 2018 10:31 am**

Since kg is the SI unit, we would want to use that over grams.

Posted: **Wed Oct 24, 2018 11:11 am**

mostly all the equations we were taught in the quantum world chapter use kilograms as the unit for mass since kg is the SI unit.

Posted: **Wed Oct 24, 2018 11:12 am**

All equations in this chapter use kilograms because it is the SI base unit. In addition, in any equation which deals with Joules, kilograms is always used for the mass in order to make sure that the units of both cancel.

Posted: **Wed Oct 24, 2018 6:52 pm**

I remember in class Lavelle said he wanted us to use kg since it is the SI unit for mass. That way, with all the equations the units will be able to cancel out.

Posted: **Thu Oct 25, 2018 12:45 am**

Use kg as that is the SI unit. Fun fact: the reason kg the SI unit and not g is simply because a king wanted it that way! Here's the link if you'd like to learn more: https://physics.stackexchange.com/quest ... ic-si-unit