Rounding EF to Integers

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Anya Holbrook 1E
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Joined: Wed Sep 30, 2020 9:38 pm

Rounding EF to Integers

Postby Anya Holbrook 1E » Wed Oct 07, 2020 4:04 pm

If we have to find the empirical formula before finding the molecular formula of a compound (where the molecular formula is what we are looking for in the end), is it absolutely necessary that we make the empirical formula integers only? Or can we leave the EF as decimals if necessary then just continue on to finding the MF?

Nathan Lao 2I
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Re: Rounding EF to Integers

Postby Nathan Lao 2I » Wed Oct 07, 2020 4:11 pm

I'm not sure if it's absolutely necessary but I think it's a lot easier to find the molecular formula in the end using whole number integers in the empirical formula. From there it's just a matter of comparing the molar mass of the empirical formula to the given molar mass to determine the molecular formula. Hope this helps!

Astha Patel 2J
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Re: Rounding EF to Integers

Postby Astha Patel 2J » Wed Oct 07, 2020 4:12 pm

Since you use the empirical formula's molecular mass to solve for the molecular formula (using the molecular mass usually given in the context of the problem), it makes calculations easier if Empirical formulas are in the lowest whole numbers. You'll still get the correct answer using decimals but it may be tricker especially if the problem asks for empirical formula as well.

Christine Ma 3L
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Re: Rounding EF to Integers

Postby Christine Ma 3L » Wed Oct 07, 2020 4:13 pm

Empirical formulas should be the smallest whole number ratios of the elements in the formula, and I think having them as integers to begin with would make finding the molecular formula easier, because molecular formulas should be integer multiples of the empirical formula.
Last edited by Christine Ma 3L on Wed Oct 07, 2020 4:15 pm, edited 1 time in total.

Chanel Mao 3D
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Re: Rounding EF to Integers

Postby Chanel Mao 3D » Wed Oct 07, 2020 4:13 pm

Hi!

Just to clarify, an empirical formula refers to the simplest integers ratio of atoms present in a molecule, so yes, I would say that it is necessary to make the empirical formula integers only. Hope this helps! Let me know if you have any more questions!

Brianne Conway 1D
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Re: Rounding EF to Integers

Postby Brianne Conway 1D » Wed Oct 07, 2020 4:18 pm

As everyone else said, I think it would be easier to just convert it to integers, but if you like to leave it with decimals you probably can as long as the question doesn't actually ask for the empirical formula.

David Liu 1E
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Re: Rounding EF to Integers

Postby David Liu 1E » Wed Oct 07, 2020 4:20 pm

If you're using molecular mass, you should get the empirical formula already in it's simplest state without decimals after calculating. You'll use whole numbers for the molecular formula too, so I think that even if you were to somehow get decimals it would be easier to work with whole numbers for the empirical formula.


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