Question

Volume of a gas at STP is $1.12\times 10^{-7}$ cc.Calculate the no. 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

Answer: (B)

No. of molecules $=\frac{1.12\times 10^7}{22,400}g$
$=\frac{10^{-9}}{200}$
$=0.5\times 10^{-11}$ moles
$=0.5\times 10^{-}11\times 6.02\times 10^{23}$
$=3.01\times 10^{12}$ molecules