Question

The total number of electrons present in $1.4g$ of dinitrogen gas is

• A. $4.2\times 10^{-23}$ electrons
• B. $3.2\times 10^{23}$ electrons
• C. $4.2\times 10^{23}$ electrons
• D. $3.2\times 10^{-23}$ electrons

Answer 1

Answer: (C)

Number of moles of dinitrogen $=\frac{1.4}{28}=0.05$
Number of molecules in $1.4g$ of dinitrogen
$=0.05\times 6.022\times 10^{23}$ molecules
$=0.3011\times 10^{23}$ molecules $=3.011\times 10^{22}$ molecules
$\because 1$ molecule of dinitrogen has $14$ electrons.
$\therefore 3.011\times 10^{22}$ molecules of dinitrogen have
$=14\times 3.011\times 10^{22}$ electrons
$=42.154\times 10^{22}$ electrons $=4.2154\times 10^{23}$ electrons