Chapter 10.1, Problem 1PP

Interpretation Introduction

Interpretation:

The number of Zn atoms in 2.50 mol of Zn 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 1PP

The number of Zn atoms is $1.51\times {10}^{24}$. Since, Zn is an element thus, the units present are atoms.

Explanation of Solution

Given information:

The number of moles of Zn element is 2.50 mol.

Calculation:

The number of moles can be converted into number of units using the following conversion factor:

$\begin{array}{l}1{\text{ mole = N}}_{\text{A}}\\ \text{1 mole = 6}\text{.022}\times {\text{ 10}}^{23}\text{ units}\end{array}$

Thus, in $\text{2}\text{.50 mol of Zn}$, the number of Zn atoms can be calculated as follows:

$N=n\times N_A$

Putting the values,

$\begin{array}{l}N=\left(2.50\text{ mol}\right)\left(6.022\times {10}^{23}\text{ atoms/mol}\right)\\ =1.51\times {10}^{24}\text{ atoms}\end{array}$

Conclusion

Thus, in 2.50 mol of Zn there are $1.51\times {10}^{24}$ atoms.