Problem: Cumene is a compound containing only carbon and hydrogen that is used in the production of acetone and phenol in the chemical industry. Combustion of 47.6 mg cumene produces some CO2 and 42.8 mg water. The molar mass of cumene is between 115 and 125 g/mol. Determine the empirical and molecular formulas.

FREE Expert Solution

We’re being asked to determine the empirical formula of cumene which is composed of C and H given the combustion analysis.


Recall that in combustion analysisa compound reacts with excess O2 to form products. For a compound composed only of C and H, the reaction looks like this:


CxHy + O2 (excess)  x CO2y H2O


This means we need to do the following steps:

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

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

Step 3: Determine the lowest whole number ratio of C and H 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

Cumene is a compound containing only carbon and hydrogen that is used in the production of acetone and phenol in the chemical industry. Combustion of 47.6 mg cumene produces some CO2 and 42.8 mg water. The molar mass of cumene is between 115 and 125 g/mol. Determine the empirical and molecular formulas.

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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 Fedoryak's class at University of Manitoba.

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 Atoms 1st 2nd Edition. You can also practice Chemistry: An Atoms First Approach - Zumdahl Atoms 1st 2nd Edition practice problems.