Question

An organic compound contains 40% carbon and 6.66% hydrogen. Calculate the empirical formula $11.2l$ of the vapours of that substance weigh 30 g. What is the molecular formula of the compound ?

• A. $C_4{H}_8{O}_4$
• B. $C_3{H}_4{O}_2$
• C. $C_2{H}_{4}O$
• D. $C_2{H}_4{O}_2$

Answer 1

Answer: (D)

$C_2{H}_4{O}_2$

an organic compound contain 40% carbon ,6.66% hydrogen and 53.33% oxygen

mole of carbon = 4 mole

for carbon $\frac{40}{122}$= 3.33 $\frac{3.33}{3.33}$= 1 atom

for hydrogen $\frac{6.66}{1}$= 6.66 $\frac{6.66}{3.33}$= 1 atom

for oxygen $\frac{53.33}{16}$= 3.33 $\frac{3.33}{3.33}$= 1 atom

emperical formula $C{H}_{2}O$

mass 30 gram C is 60/30 = 2 atom

so formula is $C_2{H}_4{O}_2$

answer is D