Chapter 10, Problem 95A

(a)

Interpretation Introduction

Interpretation: The number of moles 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 the symbol N_A.

Answer to Problem 95A

  $2.075\times {10}^{-19}\text{ mol}$

Explanation of Solution

The number of molecules of carbon dioxide is $1.25\times {10}^{15}$ .

From the given number of moles, the number of moles can be calculated as follows:

  $n=\frac{N}{{\text{N}}_{\text{A}}}$

Putting the values,

  $n=\frac{1.25\times {10}^{15}\text{ molecules}}{6.022\times {10}^{23}\text{ molecules/mol}}=2.075\times {10}^{-19}\text{ mol}$

Thus, the number of moles of carbon dioxide is $2.075\times {10}^{-19}\text{ mol}$ .

(b)

Interpretation Introduction

Interpretation: The number of moles of sodium nitrate 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 the symbol N_A.

Answer to Problem 95A

  $5.96\times {10}^{-3}\text{ mol}$

Explanation of Solution

The given formula unit of sodium nitrate is $3.59\times {10}^{21}$ .

The above formula unit can be converted to the number of moles as follows:

  $n=\frac{N}{{\text{N}}_{\text{A}}}$

Putting the values,

  $n=\frac{3.59\times {10}^{21}\text{ formula unit}}{6.022\times {10}^{23}\text{ formula unit/mol}}=5.96\times {10}^{-3}\text{ mol}$

Thus, the number of moles is $5.96\times {10}^{-3}\text{ mol}$ .

(c)

Interpretation Introduction

Interpretation: The number of moles of calcium carbonate 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 the symbol N_A.

Answer to Problem 95A

  $4.8\times {10}^3\text{ mol}$

Explanation of Solution

The given formula unit of calcium carbonate is $2.89\times {10}^{27}$ .

The above formula unit can be converted to the number of moles as follows:

  $n=\frac{N}{{\text{N}}_{\text{A}}}$

Putting the values,

  $n=\frac{2.89\times {10}^{27}\text{ formula unit}}{6.022\times {10}^{23}\text{ formula unit/mol}}=4.8\times {10}^3\text{ mol}$

Thus, the number of moles is $4.8\times {10}^3\text{ mol}$ .