Question

An unknown compound was decomposed into 63.2 g carbon, 5.26 g hydrogen, and 41.6 g oxygen. what is its empirical formula?

Answer 1

Step 1:
Divide mass of each element with its M.mass in order to find out moles.

C = 63.2 g / 12 g/mol = Moles = 5.26 moles

H = 5.26 g / 1.008 g/mol = Moles = 5.21 moles

C = 41.6 g / 16 g/mol = Moles = 2.6 moles

Step 2:
Select moles of the element with least value and divide all moles of element by it,
C H O
5.26/2.6 : 5.21/2.6 : 2.6/2.6

2.02 : 2.00 : 1

Result:
Empirical Formula = C₂H₂O