Question

How many moles of electrons weight one kilogram?

• A. $6.02\times {10}^{23}$
• B. $\frac{1}{9.108}\times {10}^{31}$
• C. $\frac{6.02}{9.108}\times {10}^{54}$
• D. $\frac{1}{9.108\times 6.023}\times {10}^8$

Answer 1

The correct option is D $\frac{1}{9.108\times 6.023}\times {10}^8$

We know that,

Mass of electron$=9.1\times {10}^{-31}kg$

Therefore, number of electrons in 1kg$=\frac{1kg}{9.108\times {10}^{-31}kg}$

Number of moles of electrons$=\frac{\text{Number of electrons}}{\text{Avogadro's number}}$

Number of moles of electrons$=\frac{1}{(9.108\times {10}^{-31})(6.023\times {10}^{23})}$

Number of electrons$=\frac{{10}^8}{9.108\times 6.023}mol$