Lesson Notes By Weeks and Term - Senior Secondary 1

Standard separation techniques for mixtures II

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  4. Standard separation techniques for mixtures II

Term: 1st Term

Week: 6

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:       

Subject:      Chemistry

Topic:-       Standard separation techniques for mixtures II

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

  1. Explain precipitation, magnetic separation, distillation and fractional distillation

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 reviews the previous lesson on Separation techniques for mixtures

Students pay attention

STEP 2

EXPLANATION

He explains magnetic separation and precipitation

 

Students pay attention and participates

STEP 3

DEMONSTRATION

He explains distillation and fractional distillation

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

STANDARD SEPARATION TECHNIQUES FOR MIXTURES

  1. Magnetic separation; with this technique magnetic substances (usually metals) can be separated from not magnetic substances (non-metals) using a magnet.

Note: some metals are not magnetic. They include Gold, silver, aluminium, copper, zinc, etc.

  1. Precipitation is a technique used to separate a mixture based on the solubility of its components. The solubility of a compound depends on the ionic strength of the solution, its pH, and temperature. Manipulation of these factors can cause a compound to become an insoluble solid, and fall out of solution.
  2. Simple Distillation is the separation of pure liquids of wide range of boiling point from a solution by condensing vapourised liquid. Condensed pure liquid is called distillate.

Process of Distillation:

  1. Solution is heated, and steam (pure vapour) is produced.
  2. The steam is cooled in condenser to form pure liquid.
  3. Solute remains in the flask

       4. Fractional Distillation separates mixture of miscible (soluble) liquids with closed range of boiling points. Use of Fractionating column

Process of Fractional Distillation: E.g. ethanol and water

  1. Mixture of ethanol and water is placed in flask and heated.
  2. Ethanol with lower boiling point boils and vaporizes first and reach fractionating column then cools and condenses into ethanol as it passes through condenser. Temperature will stay constant until all ethanol is distilled.
  3. Water will distil the same way after all ethanol is distilled.

EVALUATION:    1. Write short notes on the following

  1. magnetic separation
  2. precipitation
  3. distillation
  4. Fractional distillation

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively