1. Physical Science Chapter 15 The Classification of Matter 1

2. 15.1 Composition of Matter The Big Idea: Matter can be classified by what it is made of, by its physical properties, and by its chemical properties. Copy this into your notebook!

3. 15.1 Composition of Matter Section 1: Matter can be either a pure substance (an element or a compound) or a mixture (either heterogeneous or homogeneous.) Copy this into your notebook!

4. 15. The Classification of Matter 15.1 Composition of Matter: Matter can be either a pure substance (an element or a compound) or a mixture (either heterogeneous or homogeneous.) 3 Copy this into your notebook!

5. 15:1 The Composition of Matter A.Substances are either elements or compounds. 1. When all the atoms in a substance are alike, the substance is an element. 4

6. 15:1 The Composition of Matter 2. A compound is a substance with two or more elements combined in a fixed proportion. 5

7. 15:1 The Composition of Matter  All substances are built from atoms. If all the atoms in a substance have the same identity, that substance is an element.  The graphite in your pencil point and the copper coating of a penny are examples of elements. 3 Elements

8. 15:1 The Composition of Matter  About 90 elements are found on earth.  More that 20 others have been made in laboratories, but most of these are unstable and exist only for short periods of time. 7 Elements

9. 15:1 The Composition of Matter Can you imagine yourself putting something made from a silvery metal and a greenish-yellow, poisonous gas on your food? 8 Compounds

10. 15:1 The Composition of Matter Table salt is a chemical compound that fits this description. Even though it looks like white crystals and adds flavor to food, its components—sodium and chlorine—are neither white nor salty. 9 Video—CompoundsVideo—Compounds 2.14 Compounds

11. 15:1 The Composition of Matter B. Two or more substances that can be easily separated by physical means form a mixture such as the pizza or soft drink shown. 10 Mixtures—Video 1.33 Mixture

12. 15:1 The Composition of Matter Heterogeneous Mixtures Unlike compounds, mixtures do not always contain the same proportions of the substances that make them up. 1. A mixture in which different materials can be easily distinguished is called a heterogeneous mixture. 11 Video—Heterogeneous Mixtures.34

13. 15:1 The Composition of Matter 12 Most of the substances you come in contact with every day are heterogeneous mixtures. Some components are easy to see, like the ingredients in pizza, but others are not. For example, the cheese in pizza is also a mixture, but you cannot see the individual components.

14. 15:1 The Composition of Matter 13 Soft drinks contain water, sugar, flavoring, coloring, and carbon dioxide gas. Soft drinks in sealed bottles are examples of homogeneous mixtures. Homogeneous Compounds

15. 15:1 The Composition of Matter 14 2.A homogeneous mixture contains two or more gaseous, liquid, or solid substances blended evenly throughout. Video—Homogeneous Mixtures.27

16. 15:1 The Composition of Matter 15 3.Another name for homogeneous mixtures like a cold soft drink is solution. A solution is a homogeneous mixture of particles so small they cannot be seen without a microscope and will never settle to the bottom of the container. Copy this into your notebook!

17. 15:1 The Composition of Matter 16 Solutions remain constantly and uniformly mixed.

18. 15:1 The Composition of Matter 17 Milk is an example of a specific kind of mixture called a colloid. Colloids 4. A colloid is a type of heterogeneous mixture with particles that are larger than those in solutions but not heavy enough to settle out.

19. 15:1 The Composition of Matter 18 One way to distinguish a colloid from a solution is by its appearance. Detecting Colloids Fog appears white because its particles are large enough to scatter light. Sometimes it is not so obvious that a liquid is a colloid. You can tell for certain if a liquid is a colloid by passing a beam of light through it.

20. A light beam is invisible as it passes through a solution, but can be seen readily as it passes through a colloid. This occurs because the particles in the colloid are large enough to scatter light, but those in the solution are not. A solution does not scatter light. Detecting Colloids The scattering of light by colloidal particles is called the Tyndall effect. Video—Colloids.46Video 2—Colloids.45

21. 15:1 The Composition of Matter 20 e Video—Suspensions 1Video—Suspensions 1.47 Video—Suspensions 2Video—Suspensions 2 1.44 Some mixtures are neither solutions nor colloids. One example is muddy pond water. 4. Suspensions—a heterogeneous mixture containing a liquid in which visible particles settle. Pond water is a suspension, which is a heterogeneous mixture containing a liquid in which visible particles settle.

22. 15:1 The Composition of Matter 21 Question 1 A. colloid B. mixture C. substance D. solution A _______ is a type of matter with a fixed composition.

23. 15:1 The Composition of Matter 22 Answer The answer is C. A substance can be either an element or a compound.

24. 15:1 The Composition of Matter 23 Question 2 A. 5 B. 10 C. 30 D. 90 How many elements are found on Earth?

25. Answer The answer is D. About 90 elements are found on Earth, and more than 20 have been made in laboratories.

26. Question 3 How are compounds different from mixtures?

27. Answer The atoms in compounds are combined in fixed proportions and cannot be separated by physical means. A mixture is made of two or more substances that can be easily separated by physical means. 26 e

28. 15.2 Properties of Matter The Big Idea: A physical property can be observed without changing the identity of the material. A chemical property describes whether it can undergo a chemical change. 27 Copy this into your notebook!

29. 15.2 Properties of Matter A. Physical Property— characteristic of a material which can be observed without changing the identity of the substance in material. Examples of physical properties are color, shape, size, density, melting point, and boiling point. 15.2 Video-Physical changesVideo-Physical changes 6.4228

30. 15:2 Physical Properties 29 Appearance How would you describe a tennis ball? You could begin by describing its shape, color, and state of matter. You can measure some physical properties, too. For instance, you could measure the diameter of the ball.

31. 15:2 Physical Properties 30 Behavior Some physical properties describe the behavior of a material or a substance. Attraction to a magnet is a physical property of the substance iron. Every substance has a specific combination of physical properties that make it useful for certain tasks.

32. 15:2 Physical Properties 31 1. Appearance –physical description of a substance 2. Behavior—how a substance acts; for example, magnetism, viscosity, ductility 3. Physical properties such as size and magnetism can be used to separate mixtures.

33. 15:2 Physical Properties 32 Using Physical Properties to Separate Look at the mixture of iron filings and sand shown. You probably won’t be able to sift out the iron filings because they are similar in size to the sand particles. What you can do is pass a magnet through the mixture.

34. 15:2 Physical Properties 33 Using Physical Properties to Separate The magnet attracts only the iron filings and pulls them from the sand. This is an example of how a physical property, such as magnetic attraction, can be used to separate substances in a mixture.

35. 15:2 Physical Properties 34 B. Physical Change—change in a substance’s size, shape or state of matter. 1. Substance does not change identity when it undergoes a physical change.

36. 15:2 Physical Properties 35 The Identity Remains the Same Iron is a substance that can change states if it absorbs or releases enough energy—at high temperatures, it melts. Color changes can accompany a physical change, too.

37. 15:2 Physical Properties 36 The Identity Remains the Same For example, when iron is heated it first glows red. Then, if it is heated to a higher temperature, it turns white.

38. 15:2 Physical Properties 37 2. Distillation is a process for separating a mixture by evaporating a liquid and condensing its vapor.

39. 15:2 Physical Properties 38 The process for separating substances in a mixture by evaporating a liquid and recondensing its vapor is distillation. Distillation It usually is done in the laboratory using an apparatus similar to that shown.

40. 15:2 Chemical Properties and Changes 39 Video—Chemical PropertyVideo—Chemical Property 1.16 The tendency of a substance to burn, or its flammability, is an example of a chemical property because burning produces new substances during a chemical change. C. A chemical property is a characteristic of a substance that indicates whether it can change chemically.

41. 15:2 Chemical Properties and Changes 40 D. When one substance changes to another substance, a chemical change has occurred. The foaming of an antacid tablet in a glass of water and the smell in the air after a thunderstorm are other signs of new substances being produced.

42. 15:2 Chemical Properties and Changes 41 The Identity Changes Clues such as heat, cooling, or the formation of bubbles or solids in a liquid are helpful indicators that a reaction is taking place. However, the only sure proof is that a new substance is produced. The only clue that iron has changed into a new substance is the presence of rust.

43. 15:2 Chemical Properties and Changes 42 Video-Chemical Change Video-Chemical Change 6.09 1. Some chemical changes are indicated by temperature change, smell, or bubble formation. Tarnish is a chemical reaction between silver metal and sulfur compounds in the air which results in silver sulfide. It can be changed back into silver using a chemical reaction.

44. 15:2 Chemical Properties and Changes 43 2. Other chemical changes occur very slowly such as the formation of rust. 3. Chemical changes can be used to separate substances such as metals from their ores.

45. 15:2 44 E. Weathering of Earth’s surface involves both physical and chemical changes. Weathering—Chemical or Physical Change? 1. Physical—big rocks split into smaller ones; streams carry rock particles from one place to another. 2. Chemical—chemical changes occur in rocks when calcium carbonate in limestone changes to calcium hydrogen carbonate due to acid rain.

46. 15:2 45 A similar chemical change produces caves and the icicle shaped rock formations that often are found in them. Chemical

47. 15:2 46 Suppose you burn a large log until nothing is left but a small pile of ashes. The Conservation of Mass At first, you might think that matter was lost during this change because the pile of ashes looks much smaller than the log did.

48. 47 The Conservation of Mass In fact, the mass of the ashes is less than that of the log.

49. 48 The Conservation of Mass However, suppose that you could collect all the oxygen in the air that was combined with the log during the burning and all the smoke and gases that escaped from the burning log and measure their masses, too. Then you would find that no mass was lost after all.

50. 49 The Conservation of Mass Not only is no mass lost during burning, mass is not gained or lost during any chemical change. F. According to the law of conservation of mass, the mass of all substances that are present before a chemical change equals the mass of all the substances that remain after the change. Video—Conservation of MassVideo—Conservation of Mass 5.5

51. 15:2 Math Skills 50 Mass of reactants = mass of products Let’s look at page 463. Problem 6 on page 465.

52. 17:2 Conservation of Mass 51 Einstein’s famous equation, E = mc 2, indicates that mass can be changed into energy and vice versa. Mass is converted to energy in nuclear reactions. Therefore, it is more accurate to acknowledge that mass— energy cannot be created or destroyed.

53. 17:2 Conservation of Mass 52 Write the Law of Conservation of Mass in your notebook. Highlight this someway. The law of conservation of mass states that matter can neither be created or destroyed. Video—Conservation of MassVideo—Conservation of Mass 1.4

54. 53 Math Practice in Text

55. 54 Question 1 A. boiling point B. density C. flammability D. melting point Which of the following is a chemical property?

56. 55 Question 2 A characteristic of a material that can be observed without changing the identity of the substances that make up the material is a _______.

57. 56 Question 2 Answer The answer is physical property. Examples of physical properties include color, shape, and density.

58. 57 Question 3 What is the law of conservation of mass?

59. 58 Question 3 Answer According to the law of conservation of mass, the mass of all substances that are present before a chemical change equals the mass of all substances that remain after the change.

60. Prepare for test coming soon! Remember, Homework is Due!