Chapter 21, Problem 21.93QP

(a)

Interpretation Introduction

Interpretation:

The complete balanced equation for the given incomplete reaction has to be written.

Concept Introduction:

Balanced Chemical equation:

A balanced chemical equation is an equation which contains same elements in same number on both the sides (reactant and product side) of the chemical equation thereby obeying the law of conservation of mass.

Answer to Problem 21.93QP

${\text{2K}}_{\left(\text{s}\right)}{\text{ + Br}}_{\text{2}}{}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{2KBr}}_{\left(\text{s}\right)}$

Explanation of Solution

To Write: The complete balanced equation for the given incomplete reaction.

Potassium and bromine reacts together and forms potassium bromide precipitate.

${\text{K}}_{\left(\text{s}\right)}{\text{ + Br}}_{\text{2}}{}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{KBr}}_{\left(\text{s}\right)}$

The balanced equation is given as follows,

${\text{2K}}_{\left(\text{s}\right)}{\text{ + Br}}_{\text{2}}{}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{2KBr}}_{\left(\text{s}\right)}$

Bromine molecule has two bromine atoms and the product potassium bromide has one bromine atom.  Potassium bromide needs coefficient two and potassium in reactant side gets coefficient two.  Now in both sides the elements are balanced.

(b)

Interpretation Introduction

Interpretation:

The complete balanced equation for the given incomplete reaction has to be written.

Concept Introduction:

Balanced Chemical equation:

A balanced chemical equation is an equation which contains same elements in same number on both the sides (reactant and product side) of the chemical equation thereby obeying the law of conservation of mass.

Answer to Problem 21.93QP

${\text{2K}}_{\left(\text{s}\right)}{\text{ + 2H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{2KOH}}_{\left(\text{aq}\right)}{\text{ + H}}_{\text{2}}{}_{\left(\text{g}\right)}$

Explanation of Solution

To Write: The complete balanced equation for the given incomplete reaction.

Potassium reacts with water to forms potassium hydroxide solution and hydrogen gas.

${\text{K}}_{\left(\text{s}\right)}{\text{ + H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{KOH}}_{\left(\text{aq}\right)}{\text{ + H}}_{\text{2}}{}_{\left(\text{g}\right)}$

The balanced equation is given as follows,

${\text{2K}}_{\left(\text{s}\right)}{\text{ + 2H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\stackrel{}{\to }{\text{2KOH}}_{\left(\text{aq}\right)}{\text{ + H}}_{\text{2}}{}_{\left(\text{g}\right)}$

Before including coefficients there are two hydrogens, one oxygen and one potassium in reactant side and there are three hydrogens, one oxygen and one potassium.  Water and potassium gets coefficient two in reactant side and potassium hydroxide gets two in product side.  Now in both sides the elements are balanced.

(c)

Interpretation Introduction

Interpretation:

The complete balanced equation for the given incomplete reaction has to be written.

Concept Introduction:

Balanced Chemical equation:

A balanced chemical equation is an equation which contains same elements in same number on both the sides (reactant and product side) of the chemical equation thereby obeying the law of conservation of mass.

Answer to Problem 21.93QP

${\text{2NaOH}}_{\left(\text{s}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}\stackrel{}{\to }{\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\left(\text{s}\right)}{\text{ + H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}$

Explanation of Solution

To Write: The complete balanced equation for the given incomplete reaction.

Sodium hydroxide reacts with carbon dioxide to form sodium carbonate precipitate and water as side product.

${\text{NaOH}}_{\left(\text{s}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}\stackrel{}{\to }{\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\left(\text{s}\right)}{\text{ + H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}$

The balanced equation is given as follows,

${\text{2NaOH}}_{\left(\text{s}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}\stackrel{}{\to }{\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\left(\text{s}\right)}{\text{ + H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}$

Sodium hydroxide in reactant side gets coefficient two because obtained product sodium carbonate has two sodium atom.  Now in both sides the elements are balanced.

(d)

Interpretation Introduction

Interpretation:

The complete balanced equation for the given incomplete reaction has to be written.

Concept Introduction:

Balanced Chemical equation:

A balanced chemical equation is an equation which contains same elements in same number on both the sides (reactant and product side) of the chemical equation thereby obeying the law of conservation of mass.

Answer to Problem 21.93QP

${\text{Li}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\left(\text{aq}\right)}{\text{ + 2HNO}}_{\text{3}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{H}}_{\text{2}}{\text{O}}_{{}_{\left(\text{l}\right)}}{\text{ + 2LiNO}}_{\text{3}}{}_{\left(\text{aq}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}$

Explanation of Solution

To Write: The complete balanced equation for the given incomplete reaction.

Lithium carbonate reacts with nitric acid which gives lithium nitrate, water and carbon dioxide.

${\text{Li}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\left(\text{aq}\right)}{\text{ + HNO}}_{\text{3}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{H}}_{\text{2}}{\text{O}}_{{}_{\left(\text{l}\right)}}{\text{ + LiNO}}_{\text{3}}{}_{\left(\text{aq}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}$

The balanced equation is given as follows,

${\text{Li}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\left(\text{aq}\right)}{\text{ + 2HNO}}_{\text{3}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{H}}_{\text{2}}{\text{O}}_{{}_{\left(\text{l}\right)}}{\text{ + 2LiNO}}_{\text{3}}{}_{\left(\text{aq}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}$

Lithium nitrate and nitric acid gets coefficient two because lithium carbonate has two lithium atoms and water has two hydrogen atoms.  Now in both sides the elements are balanced.

(e)

Interpretation Introduction

Interpretation:

The complete balanced equation for the given incomplete reaction has to be written.

Concept Introduction:

Balanced Chemical equation:

A balanced chemical equation is an equation which contains same elements in same number on both the sides (reactant and product side) of the chemical equation thereby obeying the law of conservation of mass.

Answer to Problem 21.93QP

${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\left(\text{aq}\right)}\text{ + Pb}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{PbSO}}_{\text{4}}{}_{\left(\text{s}\right)}{\text{ + 2KNO}}_{\text{3}}{}_{\left(\text{aq}\right)}$

Explanation of Solution

To Write: The complete balanced equation for the given incomplete reaction.

Potassium sulphate reacts with potassium nitrate which gives lead sulfate and potassium nitrate.

${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\left(\text{aq}\right)}\text{ + Pb}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{PbSO}}_{\text{4}}{}_{\left(\text{s}\right)}{\text{ + KNO}}_{\text{3}}{}_{\left(\text{aq}\right)}$

The balanced equation is given as follows,

${\text{K}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\left(\text{aq}\right)}\text{ + Pb}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{PbSO}}_{\text{4}}{}_{\left(\text{s}\right)}{\text{ + 2KNO}}_{\text{3}}{}_{\left(\text{aq}\right)}$

Lead nitrate has two nitrate ions, thus potassium nitrate gets coefficient two in order to balance the equation.  Now in both sides the elements are balanced.