Question

The mass of $1$ mole of electrons is :

• A. $9.1\times 10^{-28}\,g$
• B. $1.008\,mg$
• C. $0.55\,mg$
• D. $9.1\times 10^{-27}\,g$

Answer 1

Answer: (C)

One mole of electrons $= 6.023 × 10^{23}$ electrons
Mass of one electron $= 9.1 × 10^{-28} \, g$
Mass of one mole of electrons
$= 6.032×10^{23} × 9.1 × 10^{-28}\,g$
$= 5.48 × 10^{-4} \, g = 0.548 \,mg ≈ 0. 55 \,mg$