Chapter 10, Problem 137A

Interpretation Introduction

Interpretation:

The mass of a mole of electrons should be calculated if mass of one of the electrons is $9.11\times {10}^{-28}\text{ g}$.

Concept introduction:

The number of moles of a compound is defined as the ratio of the given mass of the compound to the molar or molecular mass of the compound.

The mathematical expression is given by:

Number of moles = $\frac{\text{given mass of the compound}}{\text{molar mass of the compound}}$

The one mole of any substance is equal to the Avogadro number, i.e., $6.022\times {10}^{23}$ atoms.

Answer to Problem 137A

Mass of a mole of electrons = $5.48\times {10}^{-4}\text{ g}$

Explanation of Solution

Since, one mole of any substance is equal to the Avogadro number, i.e., $6.022\times {10}^{23}$ atoms.

1 mole of electrons = $6.022\times {10}^{23}$ electrons.

Thus, mass of one mole of electrons = $6.022\times {10}^{23}\text{ electron}\times \frac{9.11\times {10}^{-28}\text{ g}}{1\text{ electron}}$

= $5.48\times {10}^{-4}\text{ g}$