Chapter 12.2, Problem 11SP

(a)

Interpretation Introduction

Interpretation:

The six-mole ratios that can be derived from the equation need to be determined.

Concept Introduction :

Mole ratios are the conversion factor by which moles of any reactant or product can be converted into any different mole of reactant or product. The mole ratio is always determined for a balanced chemical reaction.

Explanation of Solution

The equation given is:

  $\text{4Al(}s\text{)}+3{\text{O}}_2(g)\to 2{\text{Al}}_{\text{2}}{\text{O}}_3$

The six-mole ratios are as follows:

1. $\frac{1\text{ mole Al}}{\frac{3}{4}{\text{ mole O}}_2}$
2. $\frac{1\text{ mole Al}}{\frac{1}{2}{\text{ mole Al}}_2{\text{O}}_3}$
3. $\frac{1{\text{ mole O}}_2}{\frac{2}{3}{\text{ mole Al}}_2{\text{O}}_3}$
4. $\frac{1{\text{ mole O}}_2}{\frac{3}{4}\text{ mole Al}}$
5. $\frac{1{\text{ mole Al}}_2{\text{O}}_3}{2\text{ mole Al}}$
6. $\frac{1{\text{ mole Al}}_2{\text{O}}_3}{\frac{3}{2}{\text{ mole O}}_2}$

(b)

Interpretation Introduction

Interpretation:

The moles of aluminum required to form $3.7{\text{ mole Al}}_2{\text{O}}_3$ needs to be determined.

Concept Introduction :

A balanced equation is required for stoichiometric calculations. A balanced equation is an equation in which the number of atoms of each species is the same on both the reactant and product sides.

Answer to Problem 11SP

The moles of aluminum required to form $3.7{\text{ mole Al}}_2{\text{O}}_3$ is $7.4\text{ mole Al}$ .

Explanation of Solution

Mole conversion can be used to determine the moles of aluminum required to form $3.7{\text{ mole Al}}_2{\text{O}}_3$ . The mole conversion factor is:

  $\frac{1\text{ mole Al}}{\frac{1}{2}{\text{ mole Al}}_2{\text{O}}_3}\times 3.7{\text{ mole Al}}_2{\text{O}}_3=7.4\text{ mole Al}$