Question

Volume of gas at STP is $1.12\times {10}^{-7}$ cc. Calculate the number of molecules in it.

• A. $3.01\times {10}^{20}$
• B. $3.01\times {10}^{12}$
• C. $3.01\times {10}^{23}$
• D. $3.01\times {10}^{24}$

Answer 1

The correct option is B $3.01\times {10}^{12}$

given volume of gas $=1.12\times {10}^{-7}CC$

$6.023\times {10}^{23}$ molecules of any gas occupied $22400ml$ at STP

So,

$1.12\times {10}^{-7}CC$ volume occupied by

$=6.023\times {10}^{23}\times \frac{1.12\times {10}^{-7}}{22400}\{1CC=1ml\}$

$=3.01\times {10}^{12}$ molecules of gas