Question

An organic compound contains $40\%$ carbon and $6.67\%$ hydrogen by mass. Which of the following represents the empirical formula of the compound?

• A. $\text{C}{\text{H}}_2$
• B. $\text{C}{\text{H}}_2\text{O}$
• C. ${\text{C}}_2{\text{H}}_4\text{O}$
• D. $\text{C}{\text{H}}_{\text{3}}\text{O}$

Answer 1

Answer: (A)

$\text{C}{\text{H}}_2$

Element	% comp.	Atomic mass	Atomic ratio	Simplest ratio
C	40	12	40/12=3.3	3.3/3.3=1
H	6.67	1	6.67/1=6.67	6.67/3.3=3

Empisical formula $=\text{C}{\text{H}}_{\text{2}}$