BY Ms. FAIZA RANI

DA MHS PHASE - IV

Adopt 21st century teaching approaches to enhance student’s interest in Science particularly in Chemistry.

At the end of the session students will be able to:

TOPIC 21st CENTURY APPROACH

21st CENTURY SKILLS

TECHNIQUE

SOLUTIONS, SUSPENSIONS AND COLLOIDS

•Listening and Speaking skills•Questioning skills•Giving direction skills

•Communication skills•Creativity skills•Critical thinking•Self direction

PROJECT

Solution and its components Aqueous, Diluted and Concentrated

Solutions Suspensions Difference between Solutions and

Suspensions Colloids Emulsions

“The homogeneous mixture of two or more substances is called solution.”

Homogeneous mixture means, the color,

density, appearance and other physical and chemical properties are the same in every part of the solution.

SOLUTION

SOLUTE SOLVENT

(dissolved material) (dissolving medium)

e.g, salt, sugar etc e.g, water, vinegar etc

Solute (salt)

Solvent (water)

Aqua – water Solution in which water is used as

solvent.

For e.g,

Aqueous solution of sugar is prepared

by dissolving sugar in water.

If less solute is dissolved in a solvent, then it is a diluted solution

If more solute is dissolved in the solvent, it is called concentrated solution

“A mixture of an insoluble solid in a liquid is called suspension.”

Suspensions are heterogeneous mixtures. Heterogeneous mixture means the physical

and chemical properties are different throughout the mixture.

Chalk dissolved in water Sand dissolved in water Flour in water after settling suspension particles settle out

water

molecules

clay

particles

A. [solution]

B. [suspension]

C. [pure substance]

D. [colloid]

SOLUTION SUSPENSION

Homogenous mixture

All solute particles are evenly dissolved.

Solutions are

clear.

Heterogeneous mixture

Solute particles are settled down.

Suspensions are

cloudy.

SOLUTION SUSPENSION

The dissolved solute particles can’t be separated by physical method.

Light rays do not scatter on passing though solution.

The insoluble solute particles can be separated by filtration.

Light rays scatter on passing through the suspension.

“A mixture which behaves like something in between solution and suspension is called

Colloid.” Intermediate between a homogenous

mixture and heterogeneous mixture. Solute particles are mixed in such a way that

they remain evenly distributed without settling down like a solution but cloudy like a suspension.

Like suspensions, light rays scatter on passing through colloids.

(Continued)

Particles in colloids and suspensions reflect or scatter light in all directions. Solutions do not scatter light.

15.3

Cheese Toothpaste Ice cream etc

A. True

B. False

“An emulsion is made up of minute droplets of oil suspended in a liquid.”

If you mix oil and water and shake them a cloudy suspension is formed. Let the mixture rest and the oil and water will separate.

(A) (B)

An emulsifying agent (emulsifier) is any substance that keeps the parts of an emulsion

mixed together.

For example if we mix oil and water a suspension will form that over time separates. But now, if we add a few drops of liquid soap and shake the mixture the oil and water will stay mixed much longer.

Margarine Mayonnaise etc

A solution is a homogenous mixture which contains two or more solutes dissolved in a solvent.

The physical and chemical properties are the same in every part of the solution.

Light rays do not scatter on passing through the solution. A suspension is a mixture of an insoluble solid in a liquid. The composition of suspension is not same throughout the

mixture. Light rays scatter on passing through the suspension, means

light passing through the suspension will be scattered by the particles so that the light beam is visible.

Continued

The solution in which water is used as a solvent is called aqueous solution.

A solution in which the amount of dissolved solute is very small as compare to solvent is called Diluted solution. While, those solutions which contain a considerable amount of solute in a given amount of solvent are called concentrated solutions. 

Those mixtures which behave like something in between solution and suspension are called colloids. Such as Ice Cream, Tooth paste, Cheese etc 

An emulsion is made up of minute droplets of oil suspended in a liquid. Such as oil in water.

Q: Define solution and its components with examples.Q: Define the following; Aqueous solution Emulsion ColloidQ: Write down the difference between solutions and

suspensions.   

Do visit the following web site….http://www.youtube.com/watch?v=q96ljVMHYLo

Books:

Lower Secondary Science 2 by Tho Lai Hoong School Chemistry by Dr. Saifuddin

Internet Sources:

http://www.slideshare.net/hmsoh/ch08-solutions-suspensions http://www.slideshare.net/jbishopgcms/solutions-suspensions-and-colloids http://www.slideshare.net/jbishopgcms/solutions-suspensions-and-colloids http://www.youtube.com/watch?v=q96ljVMHYLo http://www.slideshare.net/joeltoh/solutions-and-suspensions-i http://woodstown.org/ACS/resources/ac/ch6/act3.pdf http://galileo.phys.virginia.edu/education/outreach/8thgradesol/MixSoln.htm http://www.suite101.com/content/simple-science-experiments-a32509