Lesson Notes By Weeks and Term - Senior Secondary 2

Oxidation reduction reaction 2

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TERM׃ 3RD TERM

WEEK FOUR

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Chemistry

Topic:- Oxidation reduction reaction 2

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

  1. Connect oxidation number with IUPAC naming convention
  2. Define oxidizing and reducing agents
  3. Identify Redox equations

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S

ACTIVITY

STEP 1

INTRODUCTION

The teacher review and connect oxidation number to IUPAC naming

Students pay

attention

STEP 2

EXPLANATION

He defines oxidizing and reducing agents to the students and explain what they do.

 

Students pay

attention and

participate

STEP 3

DEMONSTRATIO

N

He explains Redox equations and demonstrate how to calculate oxidation number of elements from compounds.

Students pay

attention and

participate

STEP 4

NOTE TAKING

The teacher writes a summarized

note on the board

The students

copy the note in

their books

 

NOTE

OXIDATION REDUCTION (REDOX) REACTIONS 2

Using the Oxidation States in Naming Compounds

In naming compounds like iron(II) sulphate and iron(III) chloride, The (II) and (III) are the oxidation states of the iron in the two compounds: +2 and +3 respectively. These intells that they contain Fe2+ and Fe3+ ions. Example

         

Formula

 

Name of the compound

 

FeCl2

Iron(II) chloride

FeCl3

Iron (III) chloride

MnO2

Manganese(IV) oxide

Mn(NO3)2

Manganese (II) nitrate

         

PbCl2

Lead(II) chloride

 

Transition metals always show difference oxidation state as shown in the table below.

Metal

Oxidation state

Fe      +2, +3

Cu     +1, +2

Mn    +2, +4, +6, +7

Non-metal elements (except fluorine) usually have more than one oxidation state.

Oxidizing and reducing agents

Oxidizing agents are substances that cause other substances to be oxidized, meaning they accept electrons in a chemical reaction. They themselves are reduced in the process. Common examples include oxygen, hydrogen peroxide, and various halogens.

Determining oxidation number

Example 1. To find the oxidation number of manganese atom in potassium tetraoxomanganate(VII), KMnO4.

[Oxidation number of K] + [ oxidation number of MN]  = 4 [ oxidation number of oxygen] = 0

Where the oxidation number of K  = +1

Oxidation number of Mn = X

Oxidation number of oxygen = -2

Therefore, (+1) + X + [4 x (-2)] = 0

                      1 + X  - 8 = 0

                          X = +7

Thus the oxidation number of manganese atom in potassium tetraoxomanganate VII is +7

Example 2. To find the oxidation number of chromium in potassium heptaoxodichromate VI

K2Cr2O7.

2[oxidation number of K] + 2[ oxidation number of chromium] + 7[oxidation number of oxygen] = 0

Where oxidation number of K   = +1

Oxidation number of chromium = X

Oxidation number of oxygen = -2

Hence, 2(+1) + 2(X)  + [7 x (-2)]  = 0

   2 + 2X - 14  =  0

      2X = +12

     X = + 6

EVALUATION:   1. What are oxidizing agents

  1. Differentiate between oxidizing agents and reducing agents
  2. 3. Determine the oxidation number of sulphur in tetraoxosulphate (VI)

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively