Question

The number of oxygen atoms in 4.4 g of $CO_2$ is

• A. $1.2 \times 10^{23}$
• B. $6 \times 10^{22}$
• C. $ 6 \times 10^{23}$
• D. $12 \times 10^{23} \, molecules $
  

Answer 1

Answer: (A)

(a) 1 mole of $CO_2 = 44 \, g \, of \, CO_2$
$ = 6.023 \times 10^{23} \, molecules$
$\therefore 4.4 \, g \, of \, CO_2 = 0.1 \, mole \, of \, CO_2$
$ = 6.023 \times 0.1 \times 10^{23} molecules$
$ = 6.023 \times 10^{22} molecules$
$ = 6.023 \times 10^{22} molecules \, of \, O_2$ $ = 2 \times 6.023 \times 10^{22} \, atoms \, of \, O_2$
$\approx 1.2 \times 10^{23} \, atoms \, of \, O_2$