Question

How many moles of electron weight one kilogram :

• A. $6.023 \times 10^{23}$
• B. $ \frac{1}{9.108 }\times10^{23}$
• C. $ \frac{6.023}{9.108 } \times 10^{54}$
• D. $ \frac{1}{9.108 \times 6.023}\times10^{8}$

Answer 1

Answer: (D)

Mass of an electron $=9.108 \times 10^{-31} \,kg$

Mass of one mole of electron

$=\left(9.108 \times 10^{-31} \times 6.023 \times 10^{23}\right)\, kg$

Then, number of mole of electron in $1 \,kg$

$=\frac{1}{9.108 \times 6.023 \times 10^{-8}} $

$=\frac{1}{9.08 \times 6.023} \times 10^{8}$ mole of $e^{-}$