Question

The difference in the mass of 100 moles each of sodium atoms and sodium ions is 5.48002 g. Compute the mass of an electron.

Answer 1

Number of electrons in Na atom = 11

Number of electrons in Na+ = 10

For 1 mole of Na atom and Na+ the difference in electrons = 1 mole

For 100 moles of Na atoms and Na ions the

difference = 100 moles of electrons

Mass of 100 moles of electrons = 0.0548002 g

Mass of 1 moles of electron = `0.0548002/100"g"`

Mass f 1 electron = `0.0548002/(100 xx 6.022 xx 10^23)`

= 9.1 × 10⁻²⁸ g

= 9.1 × 10⁻³¹ g