1. Section 2 Mixtures of Matter

2. Mixtures
Mixture:
Definition: Is a physical blend of two or more components, each of which retains its own identity and properties
The formation of a mixture is due to physical change because each substance does not change its identity
Example: Sand and salt

3. Mixtures Types of Mixtures: Heterogeneous Mixtures Homogenous Mixtures
Definition: Is a mixture in which the composition is not uniform throughout the mixture
Example:
Salad Dressing
Sand & Salt
Chocolate Milk

4. Mixtures Homogeneous Mixture
Definition: Is a mixture in which the composition is uniform throughout the mixture
Homogenous mixtures are called solutions.
Example:
Salt and water
Lemonade
Steel – A mixture of Iron and carbon
Is an alloy
An Alloy is a homogenous mixture of metals or mixture of metals and nonmetals
Gives greater strength and durability to products

5. Separating Mixtures
Most matter exists naturally in the form of mixtures. To gain an understanding of matter we need to be able to separate them
Mixtures are physically combined
The process used to separate mixtures are based on the Physical properties of the substances that make up the mixture.
Example: Mixture of Iron and sand can be separated using magnets

6. Separating Mixtures
Many techniques have been developed that use physical properties of substances to separate various mixtures.
Filtration
Separates heterogeneous mixtures composed of solids and liquids
Uses a porous barrier to separate solid from liquid
The liquid passes through & the solids are trapped

7. Separating Mixtures Distillation Separated homogeneous mixtures
Distillation: A physical separation technique that is based on differences in the boiling points of substances
Process:
Mixture is heated
Substance with lowest boiling point turns to vapor
This liquid is then condensed into a liquid and collected

8. Separating Mixtures Crystallization
Crystallization: A separation technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance.
Process:
Solution contains as much substance as it can possibly hold
Addition of a tiny amount more will cause the dissolved substance to come out of solution. Substance with lowest boiling point turns to vapor

9. Separating Mixtures Sublimation
Sublimation: A process where a solid changes to vapor without melting
Used when one solid sublimes but the other does not

10. Separating Mixtures Chromatography
Chromatography: A technique that separates the components of a mixture based on the rate that they move or based on the size of their molecules.
In other words separating out a mixture of chemicals, which are in gas or liquid form, by letting them creep past another substance, which is typically a liquid or solid

11. Separating Mixtures Mobile phase: The moving mixture
Chromatography Cont’d
Mobile phase: The moving mixture
Stationary phase: Substance that stays put
Process:
The components of the mixture moves at different rates and separate into different spots.
The rate of separation depends on the different attractive forces between the paper and the components of the mixture.
Paper Chromatography
Column Chromatography

12. Elements
Element:
Is the simplest form of matter that has a unique set of properties.
An element is a pure substance that cannot be separated into simpler substances by physical or chemical means
Each has a unique:
Name
Symbol
Usually two or three letters
First letter is always capitalized and the remaining letters are lowercase
Universally accepted by scientists
Example: Iron  Fe

13. Compounds Is methane a pure substance?
Is a pure substance made up of two or more elements that have been chemically combined in a fixed proportion
Most of the matter in the universe exists as compounds
Methane: CH4 is made up of the elements Carbon and Hydrogen
Is methane a pure substance?
Yes. Because it always has the same composition.
Is methane an element?
No because an element cannot be broken down into simpler substances

14. Separating Compounds into components
 A chemical change is a change that produces matter with a different composition. Compounds are made by chemical changes.
The properties of compounds are generally very different than the properties of the elements from which the compound is formed.
Sodium is an extremely reactive soft metal that cannot be exposed to air or water.
Chlorine is a deadly gas.
The compound sodium chloride is a mostly unreactive white solid that is essential for all living things 

15. Separating Compounds into components
Compounds can be broken into smaller components by chemical means
The process of breaking down a compound into its elements is sometimes called decomposition.
This often requires external energy
Heat
Electricity
Example: Decomposition of water
H20  H2 (g) + O2 (g)

16. Review: Classification of Matter

17. Chemical Changes Aka a Chemical Reaction
Chemical Change: A change that involves one or more substances turning into new substances.
Aka a Chemical Reaction
Substance formed has different compositions and different properties from the original substance
Terms: Decomposing, Rusting, Exploding, Burning, Oxidizing

18. Law of Conservation of Mass
Definition: The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction, it is conserved.
Equation: Mass reactants = Mass products

19. Example: What is the mass of oxygen formed in the reaction when 10
Example: What is the mass of oxygen formed in the reaction when 10.00g Mercury Oxide is converted to liquid mercury and oxygen?
Reactant
Products
Mercury (II) Oxide
Mercury +
Oxygen

20. Practice: When 22. 99g of Sodium reacts with 35. 445g of chlorine
Practice: When 22.99g of Sodium reacts with g of chlorine. What is the mass of sodium chloride that will form?

21. Practice: A 12g sample of X reacts with an unknown sample of Y
Practice: A 12g sample of X reacts with an unknown sample of Y. It forms 78.9g of XY. What is the mass of Y that forms?

22. Practice Problems: Page 78 # 5, 6, 8 Write out the chemical equation for each

23. Practice Problems: Page 78 # 5 to 9 Write out the chemical equation for each

24. The Law of Definite Proportions
A characteristic of compounds is that the elements always combine in definite proportions by mass.
The Law of definite proportions states that any chemical compound will always contain a fixed ratio of elements by mass.
Does not matter how large or small the sample is

25. The Law of Definite Proportions
Example: Water
(H20)
Gallon of water
Cup of water

26. The Law of Definite Proportions
Review: Law of Conservation of Mass
Mass Reactants = Mass Product
Mass Element 1 + Mass Element 2 = Mass Compound
The relative amounts of an element in a compound can be expressed as a percent by mass

27. Example in Book – Analysis of Sucrose Pg. 88
20g of Granulated Sugar
50g of Cane Sugar
Element
Analysis by Mass
Percent by Mass
Carbon
8.44
Hydrogen
1.30
Oxygen
10.26
Total
20.0g
Law of Conservation of Mass

28. Practice Problems Pg. 88 #19, 20, 21

29. Practice Problems Pg. 88 #19, 20, 21

30. Practice Problems Pg. 88 #19, 20, 21

31. Test 1 - Next Week Tuesday 09/27/16
Includes material covered from:
Chapter 1
Chapter 2
Chapter 3