Question

Mass of half mole of electron is about: (given: mass of electron = 9.1 x 10^-28 g) Options: A) 0.546 mg B) 0.273 mg C) 1.092 mg D) 4.55 mg

Answer 1

$\text{A mole of electrons contains about }6.022\times10^{23} \text{ electrons.} \\ \text{Hence, half a mole of electrons weigh } \frac{1}{2} (6.022\times10^{23})(9.1\times10^{-28})\text{g}=0.273 \text{ mg.}$