Question

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

Answer 1

Step 1:Given:

$\text{Volume of gas}=1.12\times {10}^{-7}\text{CC}$.

Let $N_v$ be the number of molecules present in the gas.

Step 2:To Find:

.Number of molecules.

Step 3:Calculate the number of molecules.

1. $6.023\times {10}^{23}$ molecules of any gas occupied $22400\text{ml}$ at STP.
2. So,$1.12\times {10}^{-7}\text{CC}$volume occupied by

$$\begin{gathered} N_v=6.023\times {10}^{23}\times \frac{1.12\times {10}^{-7}}{22400} \\ =3.01\times {10}^{12}\text{molecules} \end{gathered}$$

Hence, Number of molecules is $3.01\times {10}^{12}$.