Problem: Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted to produce 0.166 g of water and 0.403 g of carbon dioxide.If the molar mass is 144 g/mol, what is the molecular formula?

FREE Expert Solution

We’re being asked to determine the molecular formula of a Valproic Acid composed of C, H, and O given the combustion analysis, 0.165-g sample is combusted to produce 0.166 g of water and 0.403 g of carbon dioxide.


Recall that in combustion analysisa compound reacts with excess O2 to form products

For a compound composed of C, H, and O, the reaction looks like this:


CxHyOz + O2 (excess)  x CO2y H2O


This means we need to do the following steps:

Step 1: Calculate the mass of C and H in the compound.

Step 2: Calculate the mass of O in the compound.

Step 3: Determine the lowest whole number ratio of C, H, and O to get the empirical formula.

Step 4: Get the ratio of the molar mass and empirical mass to determine the molecular formula.


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Problem Details

Valproic acid, used to treat seizures and bipolar disorder, is composed of C, H, and O. A 0.165-g sample is combusted to produce 0.166 g of water and 0.403 g of carbon dioxide.

If the molar mass is 144 g/mol, what is the molecular formula?

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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 Combustion Analysis concept. You can view video lessons to learn Combustion Analysis. Or if you need more Combustion Analysis practice, you can also practice Combustion Analysis practice problems.

What professor is this problem relevant for?

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