## Can someone explain why we use kg for mass as the base unit?

Sisi Li 1F
Posts: 34
Joined: Mon Mar 11, 2019 12:15 am

### Can someone explain why we use kg for mass as the base unit?

In lecture, Dr. Lavelle said that kilograms was used for the base unit for mass. However, when we do conversions, we always write the powers of 10 with respect to grams. Can anyone explain why that is? Or am I misunderstanding something?

Haorui Li 1A
Posts: 30
Joined: Mon Jun 17, 2019 7:23 am

### Re: Can someone explain why we use kg for mass as the base unit?

I believe Dr.Lavelle said since the molar mass is always in grams per mole, we tend to use grams in questions and the grams tend to cancel out each other. Can someone explain more?

Sisi Li 1F
Posts: 34
Joined: Mon Mar 11, 2019 12:15 am

### Re: Can someone explain why we use kg for mass as the base unit?

I understand why using grams is ideal, but it's just the fact that kg is the base unit part that isn't clear to me.

Yen Ho Chou 1D
Posts: 28
Joined: Wed Feb 27, 2019 12:16 am

### Re: Can someone explain why we use kg for mass as the base unit?

I believe kilograms is the standard SI unit recognized internationally.

Zachary Menz 1D
Posts: 32
Joined: Wed Nov 07, 2018 12:17 am

### Re: Can someone explain why we use kg for mass as the base unit?

Kilograms are our base unit of mass because they are helpful/coherent with other units in science. The example Dr. Lavelle used in class was that of Joules, where 1J = (1 m * kg^2) / s^2.

Kelvin Chung 1C
Posts: 50
Joined: Sat Aug 24, 2019 12:15 am

### Re: Can someone explain why we use kg for mass as the base unit?

Has anyone heard from any past CHEM 14 students whether Dr. Lavelle tests us on small details like this? Or would most of the questions on the tests/quizzes/exams be like the homework problems?

Nohemi Garcia 1L
Posts: 103
Joined: Fri Aug 02, 2019 12:15 am

### Re: Can someone explain why we use kg for mass as the base unit?

I was told that the tests/quizzes are either phrased similarly to the homework problems or are actual homework problems. The smaller details may have an impact on our grades, but I'm not too sure if they will be specifically asked on the test.

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

### Re: Can someone explain why we use kg for mass as the base unit?

This is just another note to add. One common misconception I had is that 1 kg/m^3 is equal to 1 g/cm^3. This is not true, however, because you have to take into account the powers. So like Dr. Lavelle said, make sure to perform conversions beforehand.

Annika Zhang 1F
Posts: 49
Joined: Sat Jul 20, 2019 12:15 am

### Re: Can someone explain why we use kg for mass as the base unit?

I myself don't completely understand the answer to this question as well but I believe the kilogram was made to be the base unit for mass because initially, the kilogram was developed by the French government but after the revolution, the standing Republican government decided to adopt the metric system and the gram. However, the gram was seen as too small of a unit to measure most things so they adopted the kilogram.

Ethan Lam 4A
Posts: 69
Joined: Thu Jul 11, 2019 12:17 am

### Re: Can someone explain why we use kg for mass as the base unit?

It is because kilograms are more useful in real world applications than grams. Kilograms are better for measuring common objects since 4.5 kg of flour is simpler to say than 4500 g of flour.