Chapter 15.1, Problem 15.19QAP

Interpretation Introduction

(a)

Interpretation:

For the following reaction, identify the substances that is oxidized, the substance that is reduced, the oxidizing agent, and the reducing agent.

  $\text{2NiS}\left(\text{s}\right){\text{ + 3O}}_{\text{2}}\left(\text{g}\right)\to \text{2NiO}\left(\text{s}\right){\text{ +2SO}}_{\text{2}}\left(\text{g}\right)$

Concept Introduction:

In an oxidation reaction the oxidation number of the element increase or becomes more positive. In a reduction reaction the oxidation number of the element decrease or becomes more negative.

The rules for assigning oxidation number to elements are:

• For an element in its free state it is assigned an oxidation number of zero.
• Monatomic ions have oxidation number that is equal to charge of the monatomic ion.
• Alkali metals have +1 oxidation number, alkaline earth metals have +2 oxidation number and halogens are assigned -1 oxidation number.
• In most compounds H is assigned a +1 oxidation number and O is assigned a -2 oxidation number.
• For a neutral compound the summation of oxidation numbers of all elements in the compound is zero.

Interpretation Introduction

(b)

Interpretation:

For the following reaction, identify the substances that is oxidized, the substance that is reduced, the oxidizing agent, and the reducing agent.

  $S{\text{n}}^{\text{2+}}\left(\text{aq}\right){\text{ + 2Fe}}^{\text{3+}}\left(\text{aq}\right)\to {\text{Sn}}^{\text{4+}}\left(\text{aq}\right){\text{ + 2Fe}}^{\text{2+}}\left(\text{aq}\right)$

Concept Introduction:

In an oxidation reaction the oxidation number of the element increase or becomes more positive. In a reduction reaction the oxidation number of the element decrease or becomes more negative.

The rules for assigning oxidation number to elements are:

• For an element in its free state it is assigned an oxidation number of zero.
• Monatomic ions have oxidation number that is equal to charge of the monatomic ion.
• Alkali metals have +1 oxidation number, alkaline earth metals have +2 oxidation number and halogens are assigned -1 oxidation number.
• In most compounds H is assigned a +1 oxidation number and O is assigned a -2 oxidation number.
• For a neutral compound the summation of oxidation numbers of all elements in the compound is zero.

Interpretation Introduction

(c)

Interpretation:

For the following reaction, identify the substances that is oxidized, the substance that is reduced, the oxidizing agent, and the reducing agent.

  ${\text{CH}}_{\text{4}}{\text{+ 2O}}_{\text{2}}\left(\text{g}\right)\to {\text{CO}}_{\text{2}}\left(\text{g}\right){\text{ + 2H}}_{\text{2}}\text{O}\left(\text{g}\right)$

Concept Introduction:

In an oxidation reaction the oxidation number of the element increase or becomes more positive. In a reduction reaction the oxidation number of the element decrease or becomes more negative.

The rules for assigning oxidation number to elements are:

• For an element in its free state it is assigned an oxidation number of zero.
• Monatomic ions have oxidation number that is equal to charge of the monatomic ion.
• Alkali metals have +1 oxidation number, alkaline earth metals have +2 oxidation number and halogens are assigned -1 oxidation number.
• In most compounds H is assigned a +1 oxidation number and O is assigned a -2 oxidation number.
• For a neutral compound the summation of oxidation numbers of all elements in the compound is zero.

Interpretation Introduction

(d)

Interpretation:

For the following reaction, identify the substances that is oxidized, the substance that is reduced, the oxidizing agent, and the reducing agent.

  ${\text{2Cr}}_{\text{2}}{\text{O}}_{\text{3}}\left(\text{s}\right)\text{ + 3Si}\left(\text{s}\right)\to \text{4Cr}\left(\text{s}\right){\text{ + 3SiO}}_{\text{2}}\left(\text{s}\right)$

Concept Introduction:

In an oxidation reaction the oxidation number of the element increase or becomes more positive. In a reduction reaction the oxidation number of the element decrease or becomes more negative.

The rules for assigning oxidation number to elements are:

• For an element in its free state it is assigned an oxidation number of zero.
• Monatomic ions have oxidation number that is equal to charge of the monatomic ion.
• Alkali metals have +1 oxidation number, alkaline earth metals have +2 oxidation number and halogens are assigned -1 oxidation number.
• In most compounds H is assigned a +1 oxidation number and O is assigned a -2 oxidation number.
• For a neutral compound the summation of oxidation numbers of all elements in the compound is zero.