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### Empirical Formula

Posted: Sun Dec 09, 2018 11:17 pm
What is the empirical formula when mass is not equal to 100?

### Re: Empirical Formula  [ENDORSED]

Posted: Sun Dec 09, 2018 11:25 pm
Using percentages, you can calculate as though the sample were 100 g. Example: 60% O, 30% H, 10% N. Use 60 g O, 30 g H, and 10 g N.

### Re: Empirical Formula

Posted: Mon Sep 30, 2019 5:41 pm
Yes, I believe professor also said that it doesn't have to be 100g. That number is chosen to make the process of calculating the empirical formula easier. It would still work if you assumed a sample mass of 50g, you would just have masses that are half as large as if you assumed a sample mass of 100g. It is just a way of turning the percentages into a mass value.

### Re: Empirical Formula

Posted: Mon Sep 30, 2019 6:40 pm
I agree with both other answers above, but the way I think about the 100g concept is that rather than the actual mass being 100g, it is a comparison. Because of the mass percentage of an element in a given molecule will be the same whether you have 10g of the molecule or 1000g. Thus, we use an easy number to calculate with,100, to find the mass percentage.

### Re: Empirical Formula

Posted: Wed Oct 02, 2019 8:28 am
I agree with the other answers, and something else to note is you can do the problem without percentage if you just convert each element to moles and divide each element's number of moles by the smallest number of moles out of the elements you are dealing with.

### Re: Empirical Formula

Posted: Wed Oct 02, 2019 11:47 pm
When writing the empirical formula, does it matter which element in the compound goes first?

### Re: Empirical Formula

Posted: Wed Oct 02, 2019 11:55 pm
Typically, compounds are written as the cation first then the anion, or metals first then nonmetals (Hydrogen is an exception).