Chapter 7, Problem 1RQ

Interpretation Introduction

Interpretation:

The definition of mole has to be given.

Explanation of Solution

A mole corresponds to the mass of a substance that contains $\text{6}{\text{.022×10}}^{\text{23}}$ particles of the substance.  The mole is the SI unit for the amount of substance.  Its symbol is $\text{mol}\text{.}$

$\text{1}\text{mol}$ of carbon-12 has a mass of $\text{12}\text{g}$ and contains $\text{6}{\text{.022×10}}^{\text{23}}$ of carbon atoms.  While writing chemical equations the quantities are assumed to be in moles.

Example:

  ${\text{Br}}_{\text{2}}{\text{+2e}}^{\text{-}}\underset{}{\to }\text{2Br}$

In the reaction, one mole of bromine gains two moles of electrons to form two moles of bromide ions.