Chapter 10.2, Problem 22SSC

Interpretation Introduction

Interpretation:

The one − mole quantity of monatomic elements needs to be converted into mass and number of atoms.

Concept introduction:

Weight of an element is the product of molecular weight and number of moles. One mole of an element contains Avogadro’s number of atoms.

Explanation of Solution

Nobel gases are monoatomic elements.

Let us take He and Ne

Formula used:

Weight $\text{= moles × gram molecules weight}$

Number of atom $\text{= moles × 6}\cdot 022\times {10}^{23}$

Given information:

Number of moles $\text{= 1}$

Calculation:

He

Given moles $\text{= 1}$

Gram molecules weight $\text{= 4}$

Weight $\text{= moles × gram molecules weight}$

$\text{= 1 × 4}$

Therefore weight $\text{= 4}$

Number of atoms $\text{= moles × 6}\cdot 022\times {10}^{23}$

$\text{= 1 × 6}\cdot 022\times {10}^{23}$

Therefore number of atoms in $1$ mole of He is $\text{ 6}\cdot 022\times {10}^{23}$

Ne

Given moles $\text{= 1}$

Gram molecules weight $\text{= 20}\cdot \text{1797}$

Weight $\text{= moles × gram molecules weight}$

$=1\times 20\cdot 1797$

Therefore weight $=20\cdot 1797\text{ g}$

Number of atoms $\text{= moles × 6}\cdot 022\times {10}^{23}$

$\text{= 1 × 6}\cdot 022\times {10}^{23}$

Therefore, number of atoms in $1$ mole of Ne is $\text{ 6}\cdot 022\times {10}^{23}$.