1. Mixtures
Chapter 9

2. Standard:
GLE Distinguish among elements, compounds, and mixtures.

3. What are we going to learn? I CAN:
Describe three properties of mixtures.
Describe four methods of separating parts of a mixture.
Analyze a solution in terms of its solute and solvent.
Explain how concentration affects a solution.
Describe the particles in a suspension.
Explain how a colloid differs from a solution and a suspension.

4. What do we already know?
Element = a pure substance (it is in its simplest form and all particles are the same)
Compound = two or more elements that have combined because of a chemical reaction
Elements can not be broken down
Compounds can only be broken down by a chemical change

5. What is a mixture?
Mixture = a combination of two or more substances that are not chemically combined
No chemical change occurs
Each substance keeps it identity
Example: Pizza

6. Describe Three Properties of Mixtures:
Components of a mixture can be easily separated
Components each keep original properties
Proportion of components in a mixture is specific

7. Four Methods of Separating Mixtures
Physically separate it
Distillation – separation based on boiling point
Magnet – some part of a mixture may be magnetic
Centrifuge – separation by spinning

8. Four Methods of Separating Mixtures – physical means
Don’t like the toppings on your pizza? Just remove them! This is a physical change.
Evaporation of saltwater

9. Four Methods of Separating Mixtures - Distillation
Separates mixtures based on boiling points of components
Separates pure water from saltwater, crude oil into gasoline and kerosene

10. Four Methods of Separating Mixtures - Magnet
A magnet can be used to separate a mixture of iron and aluminum. (elements)
Iron is attracted to the magnet but aluminum is not.
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11. Four Methods of Separating Mixtures - Centrifuge
The different parts of blood are separated with a centrifuge. (plasma, red blood cells)
Separates mixtures by densities of components.

12. Analyze Solutions – solvent and solute
Solution = a mixture that appears to be a single substance
Composed of two or more substances that are evenly distributed
Example: Kool Aid
Within a solution:
Solute = what is being dissolved (sugar in kool aid)
Solvent = what is doing the dissolving (water in kool aid)

13. Analyze Solutions – solvent and solute
Process in which particles of a substance separate and spread evenly throughout a mixture = dissolving
A solute must be soluble, or able to dissolve, in the solvent
A substance that is insoluble, or unable to dissolve, forms a mixture that is not a solution.

14. Analyze Solutions – solvent and solute
Salt water is a solution.
Salt is soluble in water, so salt dissolves in water.
Salt = solute
Water = solvent
When two liquids or gases form a solution, substance present in largest amount is solvent.

15. Analyze Solutions (continued)
Liquid in liquid (antifreeze – alcohol in water)
Some solutions can be different states, not all are liquid
Solid in liquid (salt water)
Solid in solid(brass alloy – zinc dissolved in copper; steel alloy – carbon, other elements in iron)
Gas in Gas (dry air – oxygen in nitrogen)
Gas in liquid (soft drinks – CO2 in water)

16. Solution or Not A Solution?
Sugar and Sand…solution or not a solution?
NOT A SOLUTION...grains can be physically separated

17. Solution or Not A Solution?
Diet Soda…Solution or Not A Solution?
SOLUTION...gas is dissolved in liquid

18. Solution or Not A Solution?
Air…Solution or Not A Solution?
SOLUTION...gases are dissolved in other gases

19. Solution or Not A Solution?
Water and Oil…Solution or Not A Solution?
NOT A SOLUTION...the liquids can be physically separated

20. Solution or Not A Solution?
Chocolate Chip Cookie…Solution or Not A Solution?
NOT A SOLUTION...the chips can be physically separated from the cookie

21. How Concentration Affects a Solution
Concentration = the amount of a particular substance in a given quantity of a mixture (how much solute dissolved in a solvent)
Concentrated = contains more solute
Diluted = contains less solute
Grams of solute per mL of solvent (g/mL)

22. How Concentration Affects a Solution
lllustrate a concentrated and dilute solution.

23. Describe particles in a solution:
Solubility = the ability of one substance to dissolve in another at a given temperature and pressure
Example : Adding sugar to tea
At colder temperatures, the sugar does not dissolve as well
At warmer temperatures, the sugar dissolves quickly

24. Describe particles in a solution:

25. How to dissolve solids faster:
Mix
Heat
Crush
Stirring, shaking cause solute particles to separate , spread out more quickly in solute
Solvent particles can separate solute particles and spread them out more quickly
Crushed solute increases contact with solute when mixed

26. Suspensions
Particles of mixture are more or less distributed throughout a liquid or gas
Particles large enough to settle out; too large to stay in suspension; scatter, block light
Can be separated by filtration
Snow globe, paint, salad dressing, medicines that need to be shaken

27. Colloids
Particles of mixture are evenly distributed but not heavy enough to settle out
Can not be separated by filtration

28. Tyndall Effect
Scattering of light as light beam passes through colloid.
Particles in suspension scatter, reflect light making beam visible
Seeing headlights in fog - water droplets scatter light
Blue eyes – light scatters through translucent layer over iris
Flour or milk in water

29. Explain how a colloid differs from a solution and a suspension
Solution: Particles small, do not settle out, cannot be filtered, do not scatter light Suspension: Particles large, settle out of solution, can be filtered out, scatter light Colloid: Particle intermediate between solution and suspension, cannot be filtered out, scatter light

30. Exit Ticket
1. A mixture… A. Has substances in it that are chemically combined. B. Can always be separated using filtration. C. Contains substances that are not mixed in a definite ratio. D. All of the above 2. True or False A suspension is composed of substances that are spread evenly among each other.

31. Exit Ticket
1. Which of the following is not a solution? air in a scuba tank soft drink muddy water salt water 2. When solid iodine is dissolved in alcohol, which is the solute? Which is the solvent?