Chapter 4, Problem 125QP

Interpretation Introduction

Interpretation:

The number of oxygen atoms present in $\text{10}\text{.00 g}$ of ${\text{H}}_{\text{3}}{\text{PO}}_{\text{4}}$ is to be determined.

Concept Introduction:

The number of moles of a substance is determined by dividing the mass of the substance to its molar mass. The number of moles is calculated as follows,

$n=\frac{m}{M}$ …… (1)

Here, $n$ is the number of moles, $m$ is the mass, and $M$ is the molar mass.

Then, the number of atoms of a substance is determined by multiplying the number of moles to Avogadro's number and is given as follows,

$\text{Atoms}=n\times {\text{N}}_{\text{A}}$ …… (2)

Here, ${\text{N}}_{\text{A}}$ is Avogadro's number whose value is equal to $6.022\times {10}^{23}$ .

Substitute equation (1) in equation (2) as follows,

$n_A=\frac{m}{M}\times {\text{N}}_{\text{A}}$ …… (3)

Here, $n_{\text{A}}$ is the number of atoms of a substance.