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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Violet89 on May 09, 2012, 08:11:09 PM

Title: Calculating Moles
Post by: Violet89 on May 09, 2012, 08:11:09 PM

The molecular formula for a compound is CX4 and a 2.819 g sample of this compound contains 0.102 g of carbon. How many moles of X does the sample contain?


I am not sure where to start on this problem. Any advice or help would be much appreciated! :)

Title: Re: Calculating Moles
Post by: ramboacid on May 09, 2012, 10:41:06 PM

You know how many moles of carbon you have; you can calculate it from the mass of the carbon in the sample. If the the molecular formula for the compound is CX₄, then you know the mole ratio of C and X is 1:4.

Can you get the answer from there?

As the question asks only for the number of moles of X, the mass of the sample is actually irrelevant unless you are asked to identify element X.