I am finding the formula of a compound that has 60% Carbon, 32% Oxygen, and 8% Hydrogen. Although, when it comes to actually creating the formula I end up with a subscript of 2.5 for C, 1 for O, and 4 for H.

I know I have to double each subscript for the empirical formula, but I am not sure what to do after that in terms of getting the molecular formula.

Question

Meghan Maddox

Chemistry

29 April, 18:10

I am finding the formula of a compound that has 60% Carbon, 32% Oxygen, and 8% Hydrogen. Although, when it comes to actually creating the formula I end up with a subscript of 2.5 for C, 1 for O, and 4 for H.

I know I have to double each subscript for the empirical formula, but I am not sure what to do after that in terms of getting the molecular formula.

+1

Answers (1)

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Cody Bird · Answer 1

To determine the molecular formula of the compound, the empirical formula must be determined first. To determine the empirical formula, the percentage of each constituent is divided by its molar mass. This is shown below

Carbon = 60/12 = 5

Oxygen = 32/16 = 2

Hydrogen = 8/1 = 8

The next step is to divide each ratio by the smallest value. The smallest value is 2. It becomes

Carbon = 5/2 = 2.5

It is approximated to 3

Oxygen = 2/2 = 1

Hydrogen = 8/2 = 4

Therefore, the empirical formula is

C3H4O

From the given relative molecular mass of the compound, the molecular formula can be determined