1. Mixtures vs. Pure Substances
Lesson 13 - Mixtures vs. Pure Substances
Mixtures vs. Pure Substances
What is a mixture or a pure substance ?
What is the difference between the two?

2. Lesson 13 - Mixtures vs. Pure Substances
Mixing & Separating
Here we have two very common substances, Water and Salt
Separated, they are both pure substances
But when we mix them together we form a solution… The salt dissolves into the water
How can we separate them back into two separate substances again?

3. Lesson 13 - Mixtures vs. Pure Substances
Dissolving the Salt
We will super saturate 200 ml of water with 5 table spoons of salt
Stir the solution until the salt has completely disappeared
What happened to the salt?
Can we get it back?

4. Lesson 13 - Mixtures vs. Pure Substances
Distilling the Water
By boiling the water it turns into vapor
However, the salt particles can not stay attracted to the water particles when they turn to vapor
Therefore they are left behind… after all the water has been evaporated, only salt is left

5. Lesson 13 - Mixtures vs. Pure Substances
Mother Natures Device
Where else does this this process take place in nature?
Do we benefit from it?

6. Lesson 13 - Mixtures vs. Pure Substances
The Water Cycle

7. Lesson 13 - Mixtures vs. Pure Substances
The Break Down
All matter is either a pure substance or a mixture
The purest substances that we can break matter into are ELEMENTS

8. Lesson 13 - Mixtures vs. Pure Substances
Elements
Once a substance has been broken down into its elements, we can no longer separate it any more…
You cannot take gold bars, and separate them down any further into two other substances… gold is the last stop!!
The same goes for all of the elements

9. Lesson 13 - Mixtures vs. Pure Substances
For our purposes… We will say that pure substances are anything that is made up of a single type of matter
Examples of Pure Substances are:
Salt
Water
Oil
Aluminum

10. Lesson 13 - Mixtures vs. Pure Substances
Mixtures are a combination of two or more pure substances
There are 4 categories of Mixtures
Examples of Mixtures are:
Koolaid
Oil sands
Blood
Stew

11. Categories of Mixtures are:
Lesson 13 - Mixtures vs. Pure Substances
Categories of Mixtures are:
Mechanical Mixtures
Any mixture where the different components of the mixture can be easily seen with the naked eye
Solutions
Any mixture where the different components can not be seen separately. Solutions appear to be one pure substance

12. Categories of Mixtures are:
Lesson 13 - Mixtures vs. Pure Substances
Categories of Mixtures are:
Suspensions
This is a mixture where tiny droplets of one substance are held within another substance… eventually one will settle out!
Colloid
A cloudy mixture, but the droplets of the solute are so small, they can not be separated easily

13. Categories of Mixtures are:
Lesson 13 - Mixtures vs. Pure Substances
Categories of Mixtures are:
This is a mixture where tiny droplets of one substance are held within another substance and WON’T settle out.

14. Categories of Mixtures are:
Lesson 13 - Mixtures vs. Pure Substances
Categories of Mixtures are:
What’s the difference between a suspension and a solution?
In solution, the particles of the different substances are attracted to each other so they will not separate unless acted upon by an outside force
In suspension, DO NOT have that attraction… if we let the mixture sit still for a while, the particles would eventually settle out and separate themselves

15. Suspensions vs. Solutions
Lesson 13 - Mixtures vs. Pure Substances
Suspensions vs. Solutions
Particles in a suspension mixture will settle out over time if they stand still… solutions will not.

16. Lesson 13 - Mixtures vs. Pure Substances
The Tyndall Effect
Demo Time… Kill the lights!!!

17. Lesson 13 - Mixtures vs. Pure Substances
a HOMOGENEOUS solution is one where the different substances making up the mixture can not be seen as separate… this would be a solution
Examples are: fruit juice or salt water

18. Lesson 13 - Mixtures vs. Pure Substances
a HETEROGENEOUS mixture is one where the different substances making it up can be seen
Examples are: Soil or stew

19. Lesson 13 - Mixtures vs. Pure Substances
Solution Terms
Dissolving – The process of mixing a solute into
a solvent to form a solution
Solute – The substance that is dissolved into the solvent, usually in a lesser quantity
Solvent – The substance that has the solute dissolved into it, usually in higher quantity

20. Lesson 13 - Mixtures vs. Pure Substances
Break down of Matter
All Matter
Pure Substances
Mixtures
Mechanical
Solutions
Suspensions
+ Colloids
Heterogeneous
Homogenous

21. Lesson 13 - Mixtures vs. Pure Substances
Did we get Salt?
Looking back at our distillation process… we can see that our water from the original container has now been re purified and is in a separate container
We can also see that the salt has been left behind in the form of dry salt crystals

22. Lesson 13 - Mixtures vs. Pure Substances
Your Homework
You are being a handout that covers the material we just went over… Work on these questions and we will go over them in the next class.
For more info on this topic… you can read the following pages from the two textbooks:
Pages in the Science Focus 8 Textbook
Pages in the Science in Action 8 Textbook