Lesson Notes By Weeks and Term - Senior Secondary 2

Electrolysis 1

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TERM׃ 3RD TERM

WEEK SIX

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Chemistry

Topic:- Electrolysis 1

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

  1. Define Electrolysis
  2. Identify and explain terminologies associated with electrolysis.
  3. Explain the Electrolysis nof acidified water.

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 define and explain Electrolysis to the students.

 

Students pay

attention

STEP 2

EXPLANATION

Teacher discusses the terminologies associated with electrolysis.

Students pay

attention and

participate

STEP 3

DEMONSTRATIO

N

He discusses the Electrolysis of acidified water, Copper II sulphate and brine.

 

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

ELECTROLYSIS

Electrolysis is a chemical process in which an electric current is passed through a substance, typically an electrolyte (a liquid or solution containing ions), causing a chemical change. During electrolysis, ions in the electrolyte are driven to move toward the electrodes (anode and cathode) by the electric current. This movement of ions results in the decomposition of the electrolyte into its constituent elements or compounds.

Terminologies associated with electrolysis

  1. Electrolysis: The process in which an electric current is used to drive a non-spontaneous chemical reaction, typically in a solution containing ions (electrolyte).
  2. Electrolyte: A substance, usually a liquid or solution, that conducts electricity and contains ions that are free to move. It undergoes decomposition during electrolysis.
  3. Anion: A negatively charged ion. Anions migrate towards the anode during electrolysis.
  4. Cation: A positively charged ion. Cations migrate towards the cathode during electrolysis.
  5. Electrolytic Cell: The setup or device used for electrolysis, consisting of an electrolyte, electrodes, and an external power source.

Electrolysis of acidified water

Water is a poor conductor of electricity, but it does contain some hydrogen ions, H+, and hydroxide ions, OH-. These ions are formed when a small proportion of water molecules naturally dissociate. If water is acidified with a little dilute sulfuric acid:H+ ions are attracted to the cathode, gain electrons and form hydrogen gas

OH- ions are attracted to the anode, lose electrons and form oxygen gas

The overall balanced equation for the process is: 2H2O(l) → 2H2(g) + O2(g)

The volume of hydrogen given off is twice the volume of oxygen given off.

Electrolysis of copper(ii) sulphate

The electrolysis of copper(II) sulfate CuSO4 involves passing an electric current through a solution of copper sulfate to plate copper metal onto the cathode and release oxygen gas at the anode. The overall reaction can be divided into two half-reactions occurring at each electrode:

Electrolysis Setup:

- Electrolyte: Copper sulfate solution (CuSO4) to provide copper ions for the reaction.

- Electrodes: Copper electrodes are often used to avoid contamination.

- Cathode: Copper is plated onto the cathode.

- Anode: Oxygen gas is evolved at the anode.

 Observations

  1. Cathode: Gradual deposition of copper metal on the cathode.
  2. Anode: Formation of bubbles (oxygen gas) at the anode.
  3. Solution: The blue color of the copper sulfate solution fades over time as copper ions are depleted.

Electrolysis of brine

Brine is a solution of sodium chloride (NaCl) and water (H2O). The process of electrolysis involves using an electric current to bring about a chemical change and make new chemicals. The electrolysis of brine is a large-scale process used to manufacture chlorine from salt. Two other useful chemicals are obtained during the process, sodium hydroxide (NaOH) and hydrogen (H2).

It is important that the chlorine and sodium hydroxide produced in the process are separated they react when they come into contact with each other.

EVALUATION:   1. What is electrolysis.

2,. Identify and explain briefy 4 terym associated with electrolysis.

  1. Discuss the electrolysis of acidified water.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively