## Empirical formula set up

Deepika Pugalenthi 1A
Posts: 60
Joined: Fri Sep 28, 2018 12:24 am

### Empirical formula set up

Why do we have to use 100 grams as the starting point when trying to find the empirical formula? Thank you!!

Nancy Hu - 4E
Posts: 30
Joined: Fri Sep 28, 2018 12:28 am

### Re: Empirical formula set up

It is just a lot easier to do calculations if you change the percentage based on 100g. You don't have to do any complicated calculations.

Saima Salam 3J
Posts: 32
Joined: Fri Sep 28, 2018 12:25 am

### Re: Empirical formula set up

When we are trying to find the empirical formula, we usually take the mass percent composition and turn it into grams because percent is usually out of 100. In most cases,100 gram is convenient because it reflects the mass of each element in conjunction with the percent composition which is a fraction of 100 percent.

Jacqueline Duong 1H
Posts: 61
Joined: Fri Sep 28, 2018 12:28 am

### Re: Empirical formula set up

If I remember correctly, Lavelle said it was just easier to answer the problem since it makes it simpler and the numbers are easier to work with.

RoopshaChatterjee 1G
Posts: 30
Joined: Fri Sep 28, 2018 12:17 am

### Re: Empirical formula set up

If we start with 100g then it's easier to figure out the grams of each molecule based on the percentages given. I didn't learn to answer questions this way until recently and I think this method makes it a lot easier.

Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

### Re: Empirical formula set up

Any number of grams can technically be used to find the empirical formula, but because percentages are given as parts of 100, it makes it easier to assume that it is a 100 gram sample.

MichelleTran 1I
Posts: 40
Joined: Fri Sep 28, 2018 12:23 am

### Re: Empirical formula set up

If you use 100g, you don't have to worry about having to calculate percentages and using complicated numbers, it speeds up the process without doing too many extra steps!

Anjali 4A
Posts: 59
Joined: Fri Sep 28, 2018 12:28 am

### Re: Empirical formula set up

I think that since the empirical formula is the relative number of atoms, the easiest method is to solve the problem by imagining that the sample mass is 100g.

hannahdaijo_4H
Posts: 48
Joined: Fri Sep 28, 2018 12:27 am

### Re: Empirical formula set up

If you assume a 100g sample, it's then easier to analyze the percent composition factors and work through the problem quantitatively and qualitatively.

juleschang16
Posts: 55
Joined: Fri Sep 28, 2018 12:19 am

### Re: Empirical formula set up

It is the easiest way to think about calculating the mass percentage of each element. So usually, when you find the mass composition, it is given in a percentage. You take this percentage out of 100 grams. For example if the mass composition of carbon was 20%, it would be 20 grams.