Question

In a mixture of gases, the volume content of a gas is $0.06\%$ at $STP$. Calculate the number of molecules of the gas in $1\, L$ of the mixture.

• A. $1.613 \times10^{23}$
• B. $6.023 \times10^{23}$
• C. $1.61 \times10^{27}$
• D. $1.61 \times10^{19}$

Answer 1

Answer: (D)

Volume of gas in $1\, L = \frac {0.06}{100} = 6\times 10^{-4}L$
Number of molecules of $CO_{2} = n \times N_A$
$\frac{6\times10^{-4} }{22.4} \times6.023 \times10^{23} $
$= 1.61 \times10^{19}$