Question

What is the percent composition of $C{O}_2$?
(Atomic weights: $C=12;O=16$)

• A. $10$% $C$ and $90$% $O$
• B. $14$% $C$ and $86$% $O$
• C. $18$% $C$ and $82$% $O$
• D. $27$% $C$ and $73$% $O$

Answer 1

Answer: (D)

$27$% $C$ and $73$% $O$

Molecular weight of $C{O}_2$ is $44grams$ that is [$12$ $+$ ($2$$\times$$16$)].

$12grams$ of Carbon are present in $44grams$ of Carbon Dioxide.

Thus, percentage by weight of Carbon in $C{O}_2$ is $\frac{12}{44}$$\times$$100$, which is almost equal to $27$%

$32grams$ of Oxygen are present in $44grams$ of Carbon Dioxide.

Thus, percentage by weight of Oxygen in $C{O}_2$ is $\frac{32}{44}$$\times$$100$, which is almost equal to $73$%

Thus option $D$ is the correct answer. $27$% $C$ and $73$% $O$.