Fundamentals F.25

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Brittney Hun 2C
Posts: 104
Joined: Wed Sep 11, 2019 12:15 am

Fundamentals F.25

Postby Brittney Hun 2C » Thu Oct 03, 2019 11:35 am

Question 25 on the fundamentals F asks to write the empirical and molecular formulas of two molecules (given the picture). The hint says to write the molecular formula first, which is derived from the picture. Although, I am not entirely sure how to get the empirical formula after finding the mass composition and counting the atoms for the molecular formula. How will I find the mass of the empirical formula to do the calculation?

Parker Smith
Posts: 102
Joined: Thu Jul 25, 2019 12:15 am

Re: Fundamentals F.25

Postby Parker Smith » Thu Oct 03, 2019 11:40 am

The way I found the empirical formula was by reducing each atoms subscripts down to their lowest whole integers. For example, if the molecular formula was C4H6O4, the empirical formula would be C2H3O2.

Ellis Song 4I
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Joined: Thu Jul 11, 2019 12:17 am

Re: Fundamentals F.25

Postby Ellis Song 4I » Thu Oct 03, 2019 2:09 pm

To get the empirical formula from the molecular formula, you divide the subscripts by their common factor because the empirical formula is the most simplified version of the ratio of the atoms.

Rohan Kubba Dis 4B
Posts: 50
Joined: Sat Aug 17, 2019 12:18 am

Re: Fundamentals F.25

Postby Rohan Kubba Dis 4B » Thu Oct 03, 2019 2:19 pm

Basically, on that question you count the figures of each type of element. You then have your molecular formula, which would be C4H6Cl2. That would be your molecular formula. Then, you would divide by the greatest common factor. In essence, divide by 2 and you would get C2H3C6, which would be your empirical formula. You don’t need the molar mass in this equation, however if you still want it, you could just use the periodic table at this point and assess its value.

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