what is the empirical formula of a compound composed of 3.25% hydrogen and 19.36% carbon and 77.39% oxygen by Mass

3.25 g H (1 H / 1.008 g H) = 3.22

19.36 g C (1 C / 12.01 g C) = 1.61

77.39 g O (1 O / 15.9994 g O) = 4.84

Take the smallest number calculated and divide the others by it.

1.61/1.61 = 1

C = 1.

3.22/1.61 = 2

H = 2

4.84/1.61 = 3

O = 3

=CH2O3