Chapter 10, Problem 90A

Determine the number of representative particles in each substance.

a. $\text{0}\text{.250 mol of silver}$

b. $\text{8}\text{.56 }\times {\text{ 10}}^{\text{-3}}\text{ mol of sodium chloride}$

c. $\text{35}\text{.3 mol of carbon dioxide}$

d. $\text{0}\text{.425 mol of nitrogen }\left({\text{N}}_2\right)$

Interpretation Introduction

(a)

Interpretation:

The number of representative particles needs to be determined in $0.250$ mole of silver.

Concept introduction:

In 1 mol of any substance, there are $6.022\times {10}^{23}$ units of that substance. These units can be atoms and molecules. The number of units in 1 mol of any substance is known as Avogadro’s number. It is denoted by symbol N_A.

Answer to Problem 90A

The number of representative particles in the given amount of silver is $1.506\times {10}^{23}$.

Explanation of Solution

One mole of an element contains $6.022\times {10}^{23}$ number of atoms.

So, $0.250$ moles of silver will contain = $(0.250\times 6.022\times {10}^{23})=1.506\times {10}^{23}$ number of atoms.

Hence the number of representative particles in the given amount of silver are $1.506\times {10}^{23}$.

Interpretation Introduction

(b)

Interpretation:

Number of representative particles needs to be determined in $8.56\times {10}^{-3}$ mole of sodium chloride.

Concept introduction:

In 1 mol of any substance, there are $6.022\times {10}^{23}$ units of that substance. These units can be atoms and molecules. The number of units in 1 mol of any substance is known as Avogadro’s number. It is denoted by symbol N_A.

Answer to Problem 90A

The number of representative particles in the given amount of sodium chloride is $5.15\times {10}^{21}$

Explanation of Solution

The number of moles of NaCl is $8.56\times {10}^{-3}$ mol. Now, in 1 mol there are $6.022\times {10}^{23}$ molecules of NaCl thus, number of NaCl molecules in given number of moles will be:

$N=8.56\times {10}^{-3}\times 6.022\times {10}^{23} =5.15\times {10}^{21} molecules$

Interpretation Introduction

(c)

Interpretation:

Number of representative particles in 35.3 mol mole of carbon dioxide needs to be determined.

Concept introduction:

In 1 mol of any substance, there are $6.022\times {10}^{23}$ units of that substance. These units can be atoms and molecules. The number of units in 1 mol of any substance is known as Avogadro’s number. It is denoted by symbol N_A.

Answer to Problem 90A

The number of representative particles in the given amount of carbon dioxide is $2.13\times {10}^{25}$ molecule.

Explanation of Solution

$1$ mole of an element contains $6.022\times {10}^{23}$ number of atoms.

So, $35.3$ moles of carbon dioxide will contain $(35.3\times 6.022\times {10}^{23})=2.13\times {10}^{25}$ number of atoms.

Hence, the number of representative particle will be $2.13\times {10}^{25}$.

Interpretation Introduction

(d)

Interpretation:

The number of representative particles needs to be determined in $0.425$ mole of nitrogen gas.

Concept introduction:

In 1 mol of any substance, there are $6.022\times {10}^{23}$ units of that substance. These units can be atoms and molecules. The number of units in 1 mol of any substance is known as Avogadro’s number. It is denoted by symbol N_A.

Answer to Problem 90A

The number of representative particles in the given amount of nitrogen gas is $2.56\times {10}^{23}$ molecules.

Explanation of Solution

1 mole of a substance contains $6.022\times {10}^{23}$ number of representative particles.

So, $0.425$ moles of nitrogen gas will have $\left(0.425\times 6.022\times {10}^{23}\right)=2.56\times {10}^{23}$ number of molecules.

Hence the number of representative particles in the given amount of nitrogen gas is $2.56\times {10}^{23}$.