## What Unit of Mass to Use?

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

### What Unit of Mass to Use?

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?

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?

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?

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?

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?

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