Problem: A compound composed of only carbon and hydrogen is 25.2% hydrogen by mass. The empirical formula for this compound is.

FREE Expert Solution

We’re being asked to determine the empirical formula for a compound composed only of carbon and hydrogen (Hydrogen is 25.2% by mass.)


 This means we need to do the following steps:


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

Step 2: Determine the lowest whole number ratio of C and H to get the empirical formula.



Step 1: The compound is composed of C and H and we’re given the mass percent of H (25.2% C)The total mass percentage of a compound is 100%. 

This means:


100% = mass% C + mass% Hmass % C = 100% - mass % Hmass % C = 100% - 25.2%mass % C= 74.8% C

Recall that mass percent is given by:

%mass = mass XTotal massx100


Assuming we have 100 g of the compound, this means we have 74.8 g C and 25.2g H. Now, we need to get the moles of each element in the compound. 

The atomic masses are 12 g/mol C and 1 g/mol H


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Problem Details

A compound composed of only carbon and hydrogen is 25.2% hydrogen by mass. The empirical formula for this compound is.

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