A compound is composed of 19.01g C,18.48g N, 25.34g O and 1.58g H. Find the empirical and molecular formulas of this compound

Answer 1

To find the empirical formula, you want to find the lowest mole ratio of the elements. So...

19.01 g C x 1 mole C/12.01 g = 1.583 moles C

18.48 g N x 1 mole/14.01 g = 1.319 moles N

25.34 g O x 1 mole/15.99 g = 1.585 moles O

1.58 g H x 1 mole/1.008 g = 1.567 moles H

Dividing through by the lowest value (1.319), we obtain

1.20 moles C

1 mole N

1.20 moles O

1.19 moles H

Multiply all values by 5 to get whole numbers, we obtain

6 moles C

5 moles N

6 moles O

6 moles H

The empirical formula would be C₆H₆N₅O₆

You can't find the molecular formula without knowing the molar mass of the unknown compound.