Question

What would be the empirical formula of a compound that is 25.5% carbon, 6.40% hydrogen, and 68.1% oxygen?

Answer 1

Empirical formula is the simplest ratio of whole numbers of components in a compound
in 100 g of compound
C H O
mass 25.5 g 6.40 g 68.1 g
number of moles 25.5 g/12 g/mol 6.40 g/ 1 g/mol 68.1 g/ 16 g/mol
= 2.13 mol = 6.40 mol = 4.26 mol
divide by least number of moles
2.13/2.13 = 1 6.40/2.13 = 3.0 4.26/2.13 = 2.0
all rounded off
C - 1
H - 3
O - 2

empirical formula - CH₃O₂