Chapter U5.7, Problem 3E

(a)

Interpretation Introduction

Interpretation: ${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ will undergo combustion or not needs to be explained.

Concept Introduction: A wide variety of substances undergo combustion. Solid, such as wood and coal, liquids such as kerosene or methanol and gases, such as hydrogen and methane, etc. all can combust.

Answer to Problem 3E

  ${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ will not combust.

Explanation of Solution

Some generalizations about whether a substance will combust or not are as follows:

1. Ionic compounds such as, $\text{NaCl,}{\text{Fe}}_2{\text{O}}_{\text{3}}$ do not undergo combustion.
2. Molecular compounds like octane undergo combustion reactions. The combustion of compounds containing carbon and hydrogen (hydrocarbons) generally takes place.
3. Elemental metals such as magnesium, nickel, etc. undergo combustion.
4. Carbon dioxide and water do not undergo combustion.

The compound ${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ is an ionic compound composed of ${\text{Na}}^{+}$ cation and ${\text{SO}}_{\text{4}}{}^{2-}$ anion. Ionic compounds will not undergo combustion. So, ${\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ will not combust.

(b)

Interpretation Introduction

Interpretation: $\text{Cu}\text{(}s\text{)}$ will undergo combustion or not is to be explained.

Concept Introduction: Combustion is a chemical reaction in which a compound or an element undergoes a reaction with oxygen and releases energy in the form of light and heat.A wide variety of substances undergo combustion. Solid, such as wood and coal, liquids such as kerosene or methanol and gases, such as hydrogen and methane, etc. all can combust.

Answer to Problem 3E

  $\text{Cu}\text{(}s\text{)}$ will undergo combustion.

Explanation of Solution

Some generalizations about whether a substance will combust or not are as follows:

1. Ionic compounds such as, $\text{NaCl,}{\text{Fe}}_2{\text{O}}_{\text{3}}$ do not undergo combustion.
2. Molecular compounds like octane undergo combustion reactions. The combustion of compounds containing carbon and hydrogen (hydrocarbons) generally takes place.
3. Elemental metals such as magnesium, nickel, etc. undergo combustion.
4. Carbon dioxide and water do not undergo combustion.

From the above generalizations, it is clear that elemental metals undergo combustion. $\text{Cu}$ is an elemental metal. So, it will undergo combustion.

(c)

Interpretation Introduction

Interpretation: $\text{MgO}$ will undergo combustion or not is to be explained.

Concept Introduction: A wide variety of substances undergoes combustion. Combustion is a chemical reaction in which a compound or an element undergoes a reaction with oxygen and releases energy in the form of light and heat. Solid, such as wood and coal, liquids such as kerosene or methanol and gases, such as hydrogen and methane, etc. all can combust.

Answer to Problem 3E

  $\text{MgO}$ will not undergo combustion.

Explanation of Solution

Some generalizations about whether a substance will combust or not are as follows:

1. Ionic compounds such as, $\text{NaCl,}{\text{Fe}}_2{\text{O}}_{\text{3}}$ do not undergo combustion.
2. Molecular compounds like octane undergo combustion reactions. The combustion of compounds containing carbon and hydrogen (hydrocarbons) generally takes place. Elemental metals such as magnesium, nickel, etc. undergo combustion.
3. Carbon dioxide and water do not undergo combustion.

  $\text{MgO}$ is composed of ${\text{Mg}}^{2+}$ cation and ${\text{O}}^{2-}$ cation. So, it is an ionic compound. From the above generalizations, it is clear that the ionic compound will not combust. So, $\text{MgO}$ will not undergo combustion.

(d)

Interpretation Introduction

Interpretation: $\text{Na}\text{(s)}$ will undergo combustion or not is to be explained.

Concept Introduction:Combustion is a chemical reaction in which a compound or an element undergoes a reaction with oxygen and releases energy in the form of light and heat. A wide variety of substances undergoes combustion. Solid, such as wood and coal, liquids such as kerosene or methanol and gases, such as hydrogen and methane, etc. all can combust.

Answer to Problem 3E

  $\text{Na}\text{(s)}$ will undergo combustion.

Explanation of Solution

Some generalizations about whether a substance will combust or not is as follows:

1. Ionic compounds such as, $\text{NaCl,}{\text{Fe}}_2{\text{O}}_{\text{3}}$ do not undergo combustion.
2. Molecular compounds like octane undergo combustion reactions. The combustion of compounds containing carbon and hydrogen (hydrocarbons) generally takes place.
3. Elemental metals such as magnesium, nickel, etc. undergo combustion.
4. Carbon dioxide and water do not undergo combustion.

From the above generalizations, it is clear that elemental metals undergo combustion. $\text{Na}\text{(s)}$ is an elemental metal. So, it will undergo combustion.

(e)

Interpretation Introduction

Interpretation: ${\text{C}}_{\text{2}}{\text{H}}_{\text{6}}\text{O}\text{(}l\text{)}$ will undergo combustion or not is to be explained.

Concept Introduction:A wide variety of substances undergoes combustion. Solid, such as wood and coal, liquids such as kerosene or methanol and gases, such as hydrogen and methane, etc. all can combust.

Answer to Problem 3E

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{6}}\text{O}\text{(}l\text{)}$ will undergo combustion.

Explanation of Solution

Some generalizations about whether a substance will combust or not is as follows:

1. Ionic compounds such as, $\text{NaCl,}{\text{Fe}}_2{\text{O}}_{\text{3}}$ do not undergo combustion.
2. Molecular compounds like octane undergo combustion reactions. The combustion of compounds containing carbon and hydrogen (hydrocarbons) generally takes place.
3. Elemental metals such as magnesium, nickel, etc. undergo combustion.
4. Carbon dioxide and water do not undergo combustion.

  ${\text{C}}_{\text{2}}{\text{H}}_{\text{6}}\text{O}\text{(}l\text{)}$ is a compound composed of hydrogen and oxygen. From the above generalizations, it is clear that the compounds consisting of hydrogen and oxygen atoms undergo combustion. So, ${\text{C}}_{\text{2}}{\text{H}}_{\text{6}}\text{O}\text{(}l\text{)}$ will combust.

(f)

Interpretation Introduction

Interpretation: $\text{Ar}\text{(}g\text{)}$ will undergo combustion or not is to be explained.

Concept Introduction:A wide variety of substances undergoes combustion. Combustion is a chemical reaction in which a compound or an element undergoes a reaction with oxygen and releases energy in the form of light and heat. Solid, such as wood and coal, liquids such as kerosene or methanol and gases, such as hydrogen and methane, etc. all can combust.

Answer to Problem 3E

  $\text{Ar}\text{(}g\text{)}$ will not undergo combustion.

Explanation of Solution

Some generalizations about whether a substance will combust or not are as follows:

1. Ionic compounds such as, $\text{NaCl,}{\text{Fe}}_2{\text{O}}_{\text{3}}$ do not undergo combustion.
2. Molecular compounds like octane undergo combustion reactions. The combustion of compounds containing carbon and hydrogen (hydrocarbons) generally takes place.
3. Elemental metals such as magnesium, nickel, etc. undergo combustion.
4. Carbon dioxide and water do not undergo combustion.

  $\text{Ar}\text{(}g\text{)}$ is not an elemental metal but a noble gas. So, it will not undergo combustion.