Determine the empirical formula for a compound that is 32.4g carbon, 6.81g hydrogen and 10.79g oxygen.

Question

i need to know how to write the empirical formula

Answer 1

The empirical formula is the simplest whole number formula.

moles of C = 32.4 g x 1 mol/12 g = 2.7 moles C

moles H = 6.81 g x 1 mole/1 g =6.81 moles H

moles O = 10.79 g x 1 mole/16 g = 0.67 moles O

To attempt to get all whole numbers, divide all by the smallest value (0.67) to get...

moles C = 2.7/0.67 = 4.02

moles H = 6.81/0.67 = 10.1

moles O = 0.67/0.67 = 1

Empirical formula = C₄H₁₀O