Chapter 11, Problem 47A

When hydrochloric acid solution reacts with lead (ll) nitrate solution, lead (Il) chloride precipitates and a solution Of nitric acid is produced.

a. Write the balanced chemical equation for the reaction.
b. Interpret the equation in terms of molecules and formula units, moles, and mass.

Interpretation Introduction

Interpretation:

The balanced chemical equation for the reaction of hydrochloric acid with lead (II) nitrate solution that results the formation of lead(II) chloride as solid and solution of nitric acid needs to be determined.

Concept introduction:

The mole concept provides the relation between moles, mass and molar mass. The mathematical expression of mole concept can be written as:

$\text{Mole =}\frac{\text{Mass}}{\text{Molar mass}}$

1 mole of any substance contains $\text{6}\text{.022 }\times {\text{ 10}}^{\text{23}}$ number of particles or atoms or molecules.

Answer to Problem 47A

${\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{PbCl}}_{\text{2}}{}_{\text{(s) }}{\text{ + 2 HNO}}_{\text{3}}{}_{\text{(aq)}}$

Explanation of Solution

Whenthe reaction of hydrochloric acid with lead (II) nitrate solution it results the formation of lead(II) chloride as solid and solution of nitric acid. The chemical formula of reactant and products are:

Hydrochloric acid = HCl

Lead (II) nitrate = ${\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}$

Lead (II) chloride = ${\text{PbCl}}_{\text{2}}$

Nitric acid = ${\text{HNO}}_{\text{3}}$

Thus the balance chemical equation must be:

${\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{PbCl}}_{\text{2}}{}_{\text{(s) }}{\text{ + 2 HNO}}_{\text{3}}{}_{\text{(aq)}}$

Interpretation Introduction

Interpretation:

The given reaction in terms of molecules, formula units, moles and mass needs to be determined.

${\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{PbCl}}_{\text{2}}{}_{\text{(s) }}{\text{ + 2 HNO}}_{\text{3}}{}_{\text{(aq)}}$

Concept introduction:

The mole concept provides the relation between moles, mass and molar mass. The mathematical expression of mole concept can written as:

$\text{Mole =}\frac{\text{Mass}}{\text{Molar mass}}$

1 mole of any substance contains $\text{6}\text{.022 }\times {\text{ 10}}^{\text{23}}$ number of particles or atoms or molecules.

Answer to Problem 47A

${\text{1 mole Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 moles HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{1 mole PbCl}}_{\text{2}}{}_{\text{(s) }}\text{ + 2 mole}s{\text{ HNO}}_{\text{3}}{}_{\text{(aq)}}$

${\text{1 formula unit Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 molecules HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{1 formula unit PbCl}}_{\text{2}}{}_{\text{(s) }}\text{ + 2 molecule}s{\text{ HNO}}_{\text{3}}{}_{\text{(aq)}}$

$\begin{array}{l}{\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{PbCl}}_{\text{2}}{}_{\text{(s) }}{\text{ + 2 HNO}}_{\text{3}}{}_{\text{(aq)}}\\ \text{ 331 g 73 g 278 g 126 g}\end{array}$

Explanation of Solution

According to the given balance chemical reaction:

${\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{PbCl}}_{\text{2}}{}_{\text{(s) }}{\text{ + 2 HNO}}_{\text{3}}{}_{\text{(aq)}}$

Thus the reaction in terms of molecules and formula units:

${\text{1 formula unit Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 molecules HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{1 formula unit PbCl}}_{\text{2}}{}_{\text{(s) }}\text{ + 2 molecule}s{\text{ HNO}}_{\text{3}}{}_{\text{(aq)}}$

Thus the reaction in terms of moles:

${\text{1 mole Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 moles HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{1 mole PbCl}}_{\text{2}}{}_{\text{(s) }}\text{ + 2 mole}s{\text{ HNO}}_{\text{3}}{}_{\text{(aq)}}$

The reaction in terms of mass:

Molar mass of ${\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}$ = 331 g/mol

Molar mass $\text{ HCl}$ = 36.5 g/mol

Molar mass ${\text{PbCl}}_{\text{2}}$ = 278 g/mol

Molar mass of ${\text{HNO}}_{\text{3}}$ = 63 g/mol

$\begin{array}{l}{\text{Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(aq)}}{\text{ + 2 HCl}}_{\text{(aq)}}\stackrel{}{\to }{\text{PbCl}}_{\text{2}}{}_{\text{(s) }}{\text{ + 2 HNO}}_{\text{3}}{}_{\text{(aq)}}\\ {\text{1 moles Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}{}_{\text{(s)}}\text{×}\frac{{\text{331 g Pb(NO}}_{\text{3}}{\text{)}}_{\text{2}}}{{\text{1 mole SnO}}_{\text{2}}{}_{\text{(s)}}}\text{= 331 g}\\ \text{2 moles HCl×}\frac{\text{36}\text{.5 g HCl }}{\text{1 mole HCl}}\text{= 73 g}\\ {\text{1 moles PbCl}}_{\text{2}}\text{ ×}\frac{{\text{ 278 g PbCl}}_{\text{2}}}{{\text{1 mole PbCl}}_{\text{2}}}\text{= 278 g}\\ {\text{2 moles HNO}}_{\text{3}}\text{ ×}\frac{\text{63}{\text{.0 g HNO}}_{\text{3}}}{{\text{1 mole HNO}}_{\text{3}}}\text{= 126 g}\end{array}$