What Unit of Mass to Use?

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Dustin Shin 2I
Posts: 64
Joined: Fri Sep 28, 2018 12:26 am

What Unit of Mass to Use?

Postby Dustin Shin 2I » Fri Oct 12, 2018 8:17 pm

I'm confused as to what unit I should be using for mass. During the lecture, Lavelle stated that the SI unit of mass was "kilogram", but a majority of the answers to homework problems come out in terms of "grams". Can someone explain?

Megan Wong 4E
Posts: 32
Joined: Fri Sep 28, 2018 12:28 am

Re: What Unit of Mass to Use?

Postby Megan Wong 4E » Fri Oct 12, 2018 8:43 pm

The SI unit for mass, as explained by Lavelle, is kilograms due to the units of Joules which is (kg x m^2 x s^-2). However, usually when doing problems we convert to the base unit which is grams unless an equation states otherwise.

juliefilice 4A
Posts: 31
Joined: Fri Sep 28, 2018 12:27 am

Re: What Unit of Mass to Use?

Postby juliefilice 4A » Sun Oct 14, 2018 12:24 am

Yes, the SI unit for mass is kg. However, in many problems, we're dealing with amounts of samples that make most sense to express in g. In a realistic lab setting we would say 2.4 g instead of 2.4 x 10^-3 kg. So if a problem gives units in g, it's probably best to use g in your answer

Richard Ku 4H
Posts: 29
Joined: Fri Oct 05, 2018 12:16 am

Re: What Unit of Mass to Use?

Postby Richard Ku 4H » Fri Oct 26, 2018 2:01 am

Kilograms (kg) is the SI unit for mass equations. However, mass will only be used to molar calculations. If you are given grams, often times you will need to convert it to kilograms.

Sana_Mian_3G
Posts: 30
Joined: Fri Sep 28, 2018 12:23 am

Re: What Unit of Mass to Use?

Postby Sana_Mian_3G » Fri Nov 23, 2018 10:51 pm

kg are used sometimes when converting Joules. I think looking at the problem first and trying to figure out what the problem is asking will help with what units are needed.

404982241
Posts: 47
Joined: Fri Sep 28, 2018 12:17 am

Re: What Unit of Mass to Use?

Postby 404982241 » Sun Nov 25, 2018 11:32 pm

It is necessary we use Kilograms when doing calculations. Equations like the momentum p=mv require the mass in kilograms.


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