Problem: Vitamin A has a molar mass of 286.4 g/mol and a general molecular formula of C xHyE, where E is an unknown element. If vitamin A is 83.86% C and 10.56% H by mass, what is the molecular formula of vitamin A?

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FREE Expert Solution

Recall that the molecular formula of a compound is the actual molar ratio (ratio of moles) for each element.  


For Vitamin A, the general molecular formula is given as: CxHyE, where E is an unknown element. Its molar mass is known to be: 286.4 g/mol, and it also contains 83.86% C, and 10.56% H by mass. We need to find the whole number values for x and y


To solve for the molecular formula of Vitamin A we need to do these steps: 

  1. Determine mass % of E 
  2. Based on the molar mass; determine the identity of element E
  3. Determine the # of moles of C and H and E using the mass from step 1.
  4. Get the whole number mole ratio of each element. 
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Problem Details

Vitamin A has a molar mass of 286.4 g/mol and a general molecular formula of C xHyE, where E is an unknown element. If vitamin A is 83.86% C and 10.56% H by mass, what is the molecular formula of vitamin A?

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Empirical Formula concept. You can view video lessons to learn Empirical Formula. Or if you need more Empirical Formula practice, you can also practice Empirical Formula practice problems.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Lopreore's class at TULANE.

What textbook is this problem found in?

Our data indicates that this problem or a close variation was asked in Chemistry: An Atoms First Approach - Zumdahl 2nd Edition. You can also practice Chemistry: An Atoms First Approach - Zumdahl 2nd Edition practice problems.