1. Thursday, September 13, 2013 How Can Density Be Used to Identify A substance Lab

2.   What is the volume of a 36 g rock if its density is 25 g/ml?  What is the mass of a brick if its density is 8.9g/cm 3, and the bricks dimensions are 2cm x 11cm x 8cm? Bell Work 9/16

3.   Discuss Classification of Matter  Complete Classification Activity Agenda

4.   Students will be able to:  Classify matter into different categories  Use density to identify a substance Objectives

5. Classification of Matter Matter can be classified into many different categories. The next few slides we will be going over each of these categories

6. Classification of Matter  How are they similar?... Different? Only one type of matter in sample Water (H 2 O) Muddy Water

7. Classification of Matter  Pure Substance Only one type of matter in sample Water (H 2 O)

8. Classification of Matter  Pure Substances – How are they different Water (H 2 O) Gold (Au)

9. Classification of Matter  Pure Substances – Element Gold (Au) Atoms of only one type are in the substance

10. Classification of Matter  Pure Substances – Compound Water (H 2 O) Atoms of more than one type are in the substance

11. Classification of Matter  Mixture Two or more types of matter in the sample Chicken Soup

12. Classification of Matter  Mixtures – How are they different? Chicken Soup Cola

13. Classification of Matter  Heterogeneous Mixture Mixture is not the same throughout— Can identify different parts Chicken Soup

14. Classification of Matter  Homogenous Mixture Mixture is the same throughout Cola

15. A. Matter Flowchart MATTER Can it be physically separated? Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element MIXTUREPURE SUBSTANCE yesno Can it be chemically decomposed? noyes Is the composition uniform? noyes ColloidsSuspensions

16. A. Matter Flowchart  Examples:  graphite  pepper  sugar (sucrose)  paint  soda Element Hetero. Mixture Compound Hetero. Mixture Homo. Mixture

17. B. Pure Substances  Element  composed of identical atoms  EX: copper wire, aluminum foil

18. B. Pure Substances  Compound  composed of 2 or more elements in a fixed ratio  properties differ from those of individual elements  EX: table salt (NaCl)

19. Compound Example

20. C. Mixtures  Variable combination of 2 or more pure substances. HeterogeneousHomogeneous

21. Tyndall Effect  https://www.youtube.com/watch?v=S oUmz8L87Z4 https://www.youtube.com/watch?v=S oUmz8L87Z4

22. C. Mixtures  Solution  homogeneous  very small particles  no Tyndall effect Tyndall Effect  particles don’t settle  EX: rubbing alcohol

23. C. Mixtures  Colloid  heterogeneous  medium-sized particles  Tyndall effect  particles don’t settle  EX: milk

24. C. Mixtures  Suspension  heterogeneous  large particles  Tyndall effect  particles settle  EX:fresh-squeezed lemonade

25. C. Mixtures  Examples:  mayonnaise  muddy water  fog  saltwater  Italian salad dressing colloid suspension colloid solution suspension

26. Physical vs. Chemical Properties  Physical Property  Can be observed without changing the identity of the substance  Chemical Property  Describes the ability of a substance to undergo changes in identity

27. B. Physical vs. Chemical Properties  Examples:  melting pointphysical  flammable chemical  densityphysical  magneticphysical  tarnishes in airchemical

28. Physical vs. Chemical Change  Physical Change  Changes the form of a substance without changing its identity  Properties remain the same  Reversible  Chemical Change  Changes the identity of a substance  Products have different properties  Irreversible

29. Physical vs. Chemical Change  Signs of a Chemical Change  change in color or odor  formation of a precipitate (solid)  formation of a gas  change in light or heat

30. Physical vs. Chemical Change  Examples:  rusting ironchemical  dissolving in waterphysical  burning a matchchemical  melting icephysical  grinding saltphysical

31. Classifying Matter Activity  Get out a sheet of paper and put your name on the top.  Create a data chart with the following headings  Make 20 rows and label 1-20 in the column “vial number” Vial Number Name of Material Pure Substance or Mixture Element, Compound, Hetero or Homo geneous Reasoning (Why did you classify it as this?)

32. Classifying Matter Activity  You will pair up and sit with your partner on one side of each lab table with 1 group at the back table if needed.  I will come give you a vial with matter in it, you will write the name of the matter in the appropriate column, decide whether it is a pure substance or a mixture and then what type of pure substance or mixture. Then pass it on to the next group

33. Analysis 1. Which classification was hardest to determine- Element, Compound, Heterogeneous or Homogenous? Why was this the hardest one? 2. If you had to separate the heterogeneous mixtures into colloids or suspensions, what property would you look at to separate the two? 3. Determine whether each sample below is an element, compound, heterogeneous or homogeneous mixture  A BC D E