Chapter 21, Problem 21.103QP

(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 21.103QP

${\text{BaCO}}_{\text{3}}{}_{\left(\text{s}\right)}\stackrel{\text{Δ}}{\to }{\text{BaO}}_{\left(\text{s}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}$

Explanation of Solution

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

Barium carbonate undergoes decomposition while heating and gives barium oxide and carbon dioxide.

${\text{BaCO}}_{\text{3}}{}_{\left(\text{s}\right)}\stackrel{\text{Δ}}{\to }{\text{BaO}}_{\left(\text{s}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}$

The balanced equation is given as follows,

${\text{BaCO}}_{\text{3}}{}_{\left(\text{s}\right)}\stackrel{\text{Δ}}{\to }{\text{BaO}}_{\left(\text{s}\right)}{\text{ + CO}}_{\text{2}}{}_{\left(\text{g}\right)}$

Both reactants and products have same number of elements.  Thus, no need to give coefficient.  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 21.103QP

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

Explanation of Solution

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

Barium reacts with water to form barium hydroxide and hydrogen gas.

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

The balanced equation is given as follows,

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

Barium hydroxide has two hydroxide ions in product which means water needs coefficient two to balance the equation.  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 21.103QP

$\text{Mg}{\left(\text{OH}\right)}_{\text{2}}{}_{\left(\text{s}\right)}{\text{ + 2HNO}}_{\text{3}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{2H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\text{ + Mg}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}{}_{\left(\text{aq}\right)}$

Explanation of Solution

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

Magnesium hydroxide reacts with nitric acid to form magnesium nitrate solution.

$\text{Mg}{\left(\text{OH}\right)}_{\text{2}}{}_{\left(\text{s}\right)}{\text{ + HNO}}_{\text{3}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\text{ + Mg}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}{}_{\left(\text{aq}\right)}$

The balanced equation is given as follows,

$\text{Mg}{\left(\text{OH}\right)}_{\text{2}}{}_{\left(\text{s}\right)}{\text{ + 2HNO}}_{\text{3}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{2H}}_{\text{2}}{\text{O}}_{\left(\text{l}\right)}\text{ + Mg}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}{}_{\left(\text{aq}\right)}$

Nitric acid gets coefficient two because magnesium nitrate has two nitrate ions.  Water in product side gets coefficient two due to two hydroxide in magnesium hydroxide.  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 21.103QP

${\text{Mg}}_{\left(\text{s}\right)}{\text{ + NiCl}}_{\text{2}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{Ni}}_{\left(\text{s}\right)}{\text{ + MgCl}}_{\text{2}}{}_{\left(\text{aq}\right)}$

Explanation of Solution

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

Magnesium reacts with nickel chloride which gives magnesium chloride and nickel gas.

${\text{Mg}}_{\left(\text{s}\right)}{\text{ + NiCl}}_{\text{2}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{Ni}}_{\left(\text{s}\right)}{\text{ + MgCl}}_{\text{2}}{}_{\left(\text{aq}\right)}$

The balanced equation is given as follows,

${\text{Mg}}_{\left(\text{s}\right)}{\text{ + NiCl}}_{\text{2}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }{\text{Ni}}_{\left(\text{s}\right)}{\text{ + MgCl}}_{\text{2}}{}_{\left(\text{aq}\right)}$

Both reactants and products have same number of elements.  Thus, no need to give coefficient.  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 21.103QP

${\text{2NaOH}}_{\left(\text{aq}\right)}{\text{ + MgSO}}_{\text{4}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }\text{Mg}{\left(\text{OH}\right)}_{\text{2}}{}_{\left(\text{s}\right)}{\text{ + Na}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\left(\text{aq}\right)}$

Explanation of Solution

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

Sodium hydroxide reacts with magnesium sulfate which gives magnesium hydroxide and sodium sulfate.

${\text{2NaOH}}_{\left(\text{aq}\right)}{\text{ + MgSO}}_{\text{4}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }\text{Mg}{\left(\text{OH}\right)}_{\text{2}}{}_{\left(\text{s}\right)}{\text{ + Na}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\left(\text{aq}\right)}$

The balanced equation is given as follows,

${\text{2NaOH}}_{\left(\text{aq}\right)}{\text{ + MgSO}}_{\text{4}}{}_{\left(\text{aq}\right)}\stackrel{}{\to }\text{Mg}{\left(\text{OH}\right)}_{\text{2}}{}_{\left(\text{s}\right)}{\text{ + Na}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\left(\text{aq}\right)}$

sodium sulfate has two sodium atoms which gives rise to coefficient two for sodium hydroxide.  Now in both sides the elements are balanced.