Question:
Calculate the total number of electrons present in 1.4 g of dinitrogen gas.
Solution:
Molar mass of dinitrogen (N2) = 28 g mol–1
Thus, $1.4 \mathrm{~g}$ of $\mathrm{N}_{2}=\frac{1.4}{28}=0.05 \mathrm{~mol}$
$=0.05 \times 6.02 \times 10^{23}$ number of molecules
$=3.01 \times 10^{23}$ number of molecules
Now, 1 molecule of $\mathrm{N}_{2}$ contains 14 electrons.
Therefore, $3.01 \times 10^{23}$ molecules of $N_{2}$ contains $=1.4 \times 3.01 \times 10^{23}$
= 4.214 × 1023 electrons
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