Question

A compound containing 40.0% carbon, 5.7% hydrogen, and 53.3% oxygen has an atomic mass of 175 g/mol. What is the molecular formula?

Answer 1

Answer:

The Empirical formula of the compound is HCHOHCHO Formaldehyde

Explanation:

Given 4040 % carbon, 5.75.7 % hydrogen and 53.353.3 % oxygen has an atomic mass of 175 g/mol.

Assuming 100 gm100gm of the compound then Carbon is 4040 gm

Oxygen is 6.76.7 gm

Hydrogen is 53.353.3 gm

Calculation of moles of each element

Moles of Carbon 4040 gm C×\frac{1 mole C}{12.01 C}

12.01C

1moleC

=3.331 C3.331C

Moles of Hydrogen 6.76.7 gm H ×\frac{1 mole H}{1.008 H}

1.008H

1moleH

=6.65 H6.65H

Moles of Oxygen 53.353.3 gm O ×\frac{1 mole H}{16.00 O}

16.00O

1moleH

=3.331 O3.331O

In order to get the ratio, we divide each number of moles by the smallest number.

The ratio if C:H:O =1:2:1

Thus the empirical formula CH2OCH2O that is HCHOHCHO Formaldehyde