A compound is 86% carbon and 14% hydrogen by mass. What is the empirical formula for this compound?
A. CH
B. CH2
C. CH3
D. CH4
Step 1: change percent to grams.
Step 2: find out how many moles you have of C and H by: 86 g / 12 g per mole of C = 7 moles of C; 14 / 1 g per mole H = 14 moles of H.
Step 3: find the ratio of moles of C and H to each other: 14 / 7 is 2.
In other words there are 2 H moles for every C mole or CH2. This is the empirical formula.