Empirical formula set up

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

Empirical formula set up

Postby Deepika Pugalenthi 1A » Fri Oct 05, 2018 9:57 am

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

Postby Nancy Hu - 4E » Fri Oct 05, 2018 10:00 am

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

Postby Saima Salam 3J » Fri Oct 05, 2018 10:06 am

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

Postby Jacqueline Duong 1H » Fri Oct 05, 2018 4:33 pm

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

Postby RoopshaChatterjee 1G » Fri Oct 05, 2018 8:13 pm

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.

Harshita Talkad 4L
Posts: 60
Joined: Fri Sep 28, 2018 12:16 am

Re: Empirical formula set up

Postby Harshita Talkad 4L » Sat Oct 06, 2018 9:34 pm

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
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Joined: Fri Sep 28, 2018 12:23 am

Re: Empirical formula set up

Postby MichelleTran 1I » Sat Oct 06, 2018 9:36 pm

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
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Joined: Fri Sep 28, 2018 12:28 am

Re: Empirical formula set up

Postby Anjali 4A » Sat Oct 06, 2018 10:20 pm

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

Postby hannahdaijo_4H » Sat Oct 06, 2018 10:23 pm

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

Postby juleschang16 » Sun Oct 07, 2018 6:24 pm

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.


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