Question

A compound that contains only carbon, hydrogen, and oxygen is 48.64% C and 8.16% H by mass. What is the empirical formula of this substance? 84. The most common form

Answer 1

Answer:

The empirical formula of this substance is:

$C_3H_6O_2$

Explanation:

To find the empirical formula of this substance we need the molecular weight of the elements Carbon, Hydrogen and Oxygen, we can find this information in the periodic table:

- C: 12.01 g/mol

- H: 1.00 g/mol

- O: 15.99 g/mol

With the information in this exercise we can suppose in 100 g of the substance we have:

C: 48.64 g

H: 8.16 g

O: 43.2 g (100 g - 48.64g - 8.16g= 43.2 g)

Now, we need to divide these grams by the molecular weight:

$C=\frac{48.64g}{12.01 g/mol} =4.05 mol\\H=\frac{8.16g}{1.00g/mol}= 8.16 mol\\O=\frac{43.2g}{15.99 g/mol} = 2.70 mol$

We need to divide these results by the minor result, in this case O=2.70 mol

$C=\frac{4.05mol}{2.70mol}= 1.5\\H= \frac{8.16mol}{2.70 mol} = 3.02 \\O=\frac{2.70mol}{2.70mol} = 1$

We need to find integer numbers to find the empirical formula, for this reason we multiply by 2:

$C= 1.5*2=3\\H= 3.02*2= 6.04 \\O= 1*2=2$

This numbers are very close to integer numbers, so we can find the empirical formula as  subscripts in the chemical formula:

$C_3H_6O_2$