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%.
Recall that mass percent is given by:
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
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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