Question

(i) Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons.

Answer 1

(i) Mass of one electron = 9.10939 × 1031 kg
∴ Number of electrons that weigh 9.10939 × 1031 kg = 1
Number of electrons that will weigh 1 g = (1 × 103 kg)
= $\frac{1}{9.10039}$ × 10-31 kg × (1 × 10-3 kg)
= 0.1098 × 103 + 31
= 0.1098 × 1028
= 1.098 × 1027
(ii) Mass of one electron = 9.10939 × 1031 kg Mass of one mole of electron
= (6.022 × 1023) × (9.10939 ×1031 kg)
= 5.48 × 107kg
Charge on one electron = 1.6022 × 1019 coulomb
Charge on one mole of electron = (1.6022 × 1019 C) (6.022 × 1023)
= 9.65×10 4C