Question

300 grams of a compound which contains only carbon, hydrogen and oxygen is analyzed and found to contain the exact same percentage of carbon as it has oxygen. The percentage of hydrogen is known to be 5.98823%. Find the empirical formula of the compound

Answer 1

The empirical formula of the compound is C₄H₅O₃.

Explanation:

If hydrogen % = 5.98823, the Sum of C+O = 94.01177% or 47.005885% each

The original mass of 300 g is not important

C = 47.005885 / 12.011 = 3.913569

H = 5.98823 / 1.008 = 5.94070  

O = 47.005885 / 15.999 = 2.93805  

Divide by the smallest number:      

C =1.33  

H = 2.022

O = 1

Multiply through by 3

C = 4

H =6

O = 3

The empirical formula of a compound = C₄H₆O₃

Do not be confused by the 300 g. It is totally irrelevant to the question because you are dealing with % amounts. It would only have been of importance if you were given some mass values.