Answer
$C_4 H_8 O$
Work Step by Step
Step 1:
Use $CO_2$ and $H_2 O$ to get the mass of Carbon and Hydrogen, respectively.
Mass of carbon = $2.92 \times \frac{12~C}{44~CO_2 } = 0.7963~grams$
Mass of hydrogen= $1.22 \times \frac{2~H}{18~H_2 O} = 0.1356~grams$
Mass of oxygen = 1.20 - (0.7963 + 0.1356) = 0.2681 grams.
Step 2:
Calculate the number of moles
C = 0.7963/12 = 0.06636
H = 0.1356/1 = 0.1356
O = 0.2681/16 = 0.01676
Step 3
Divide by the smallest number of mole
C = 0.06636/0.01676 = 3.959 = 4
H = 0.1356/0.01676 = 8.091 = 8
O = 0.01676/0.01676 = 1 = 1
The molecular formula will be $C_4 H_8 O$
