Class 11 Chemistry Chapter 2 Question 2.1: (i) Calculate the number of electrons which will together weigh one gram. (ii) Calculate the mass and charge of one mole of electrons.

Class 11 Chemistry Chapter 2 Question 2.1

Question 2.1: (i) Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons.

Ans 2.1: (i) Mass of one electron = 9.1 × 10^–31 kg
Number of electrons that weigh 9.1 × 10^–31 kg = 1
Number of electrons that will weigh 1 g i.e 1 × 10^–3 kg = 1 × 10^–3 kg/ 9.1 × 10^–31 kg
= 0.1098 × 10^{–3 + 31}
= 0.1098 × 10²⁸ = 1.098 × 10²⁷

(ii) Mass of one electron = 9.1 × 10^–31 kg
Mass of one mole of electron = (6.022 × 10²³) × (9.1 ×10^–31 kg)
= 5.48 × 10^–7 kg
Charge on one electron = 1.6022 × 10^–19 coulomb
Charge on one mole of electron = (1.6022 × 10^–19 C) (6.022 × 10²³) = 9.65 × 10⁴ C

Class 11 Chemistry Chapter 2 Question 2.1