1. Properties of MAtter

2. Objectives Identify properties of amtter as extensive or intensive
Define physical property and list several common physical properties of substances
Differentiate among three states of matter
Describe a physical change

3. Key Concepts
How can properties used to describe matter be classified?*
Why do all samples of substance have the same intensive properties?*
What are three states of matter?*
How can physical changes be classified?*

4. Describing MAtter
Properties used to describe matter can be classified as extensive or intensive*

5. Describing MAtter 2 properties used to describe matter:
Extensive property
Intensive property

6. Extensive property Depends on the amount of matter in a sample
Common extensive properties:
Mass – measure of the amount of matter the object contains (grams)
Volume – measure of space occupied by the object
Length
Particle number
Electrical charge
Don’t confuse mass with weight (a measure of gravity)

7. Intensive property Depends on the type of matter in a sample
Common intensive properties:
Density – mass per unit volume
Melting point and boiling point – temp at which substance melts or boils
Magnetization

8. Identifying substance
Substance – matter that has a uniform and definite composition
Every sample of a given substance has identical properties because each sample is the same

9. Properties Words that describe matter
2 types of identifying properties:
Physical property
Chemical property

10. Physical property
Property that can be observed and measured without changing the material’s composition
Examples:
Color
Hardness
Melting point
Boiling point

11. Chemical property
Property that can only be observed by changing the composition of the material
Examples:
Ability to burn
Decomposition
Fermentation
Fermentation – metabolic process converting sugar to acid

12. Recap Properties describing matter Extensive Intensive
Properties identifying matter
Physical
Chemical

13. States of matter*

14. Solid Definite shape and volume Does not flow
Does not take shape of container
Increase in temperature = small expansion
Does not compress
Compressibility = measure of volume change resulting from pressure

15. Liquid Definite volume Take the shape of container Flows
Increase in temperature = small expansion
Does not compress

16. Gas
No definite volume
No definite shape – will take shape of container
Flows
Increase in temperature results in large expansion
Can be compressed

17. Gas (Vapor)
Substance that is currently a gas but normally is a liquid or solid at room temperature
Occurs with an increase in temperature
“Water vapor”

19. Plasma 4th state of matter Formed at high temperatures
Ionized phase of matter as found in the sun

20. Examples of each

21. Copper phases - solid

22. Copper phases - liquid

23. Copper phase – vapor (Gas)

24. Physical vs. chemical change
Physical change – changes the visible appearance, without changing the composition of the material
Boil, melt, cut, bend, split
Is boiled water still water?
Can be reversible or irreversible*

25. Physical vs. chemical change
Chemical change – change where a new form of matter is formed
Rust, burn, decompose
Irreversible

26. Assessment
In what way are liquids and gases alike? In what way are liquids and solids different?
Why do all samples of a given substance have the same intensive properties?

27. Mixtures

28. objectives Categorize a sample of matter as a substance or a mixture
Distinguish between homogeneous and heterogeneous samples of matter
Describe two ways that components of mixtures can be separated

29. Key Concepts How can mixtures be classified?*
How can mixtures be separated?*

30. mixtures Mixture – made of 2 or more different components
Classified as either:*
Heterogeneous mixture
Homogeneous mixture

31. Heterogeneous mixture
Mixture is not uniform in composition
Examples:
Chocolate chip cookie
Soil

32. Homogeneous mixture Mixture with same composition throughout
AKA “solution”
Examples:
Kool-aid
Salt water

33. Solutions
Mixed molecule by molecule thus too small to see different parts but no definite composition
Can occur between any state of matter
Gas in gas
Gas in liquid
Solid in liquid

34. phase Any part of a sample with uniform composition of properties
How many phases in a homogeneous mixture?
How many phases in a heterogeneous mixture?

35. Separating mixtures
Some mixtures can be separated easily by physical means
Can you name some?
Differences in physical properties can be used to separate mixtures*

36. filtration
Separates a solid from the liquid in a heterogeneous mixture

37. Paper chromatography
Separate components of dyes such as ink

38. distillation Takes advantage of different boiling points
Liquid is boiled to produce vapor that is then condensed to liquid
Separate homogeneous mixtures

39. assessment
Classify each of the following as homogeneous or heterogeneous:
Food coloring
Ice cubes in water
Mouthwash
Mashed, unpeeled potatoes

40. Assessment
How are a substance and a solution similar? How are they different?
When would you use filtration to separate a mixture? When would you use distillation?

41. Elements and compounds

42. objective Explain the difference between an element and a compound
Distinguish between a substance and a mixture
Identify the chemical symbols of elements and name elements given their symbols

43. Key concepts How are elements and compounds different?*
How can substances and mixtures be distinguished?*
What do chemists use to represent elements and compounds?*

44. Elements and compounds
Substances are classified as either elements or compounds

45. element Simplest kind of matter
Cannot be broken down any simpler and still have properties of that element
All one kind of atom
Elements are found on the periodic table

46. compounds Substance that can be broken down only by chemical methods
Made of 2 or more elements chemically combined in fixed proportion
When broken down, the pieces have completely different properties than original compound

47. Element vs. compound
Compounds can be broken down into similar substance by chemical means
Elements cannot*

49. Compound vs. mixture Compound Mixture Made of one kind of material
Made of more than one kind of material
Made by a chemical change
Made by a physical change
Definite composition
Variable composition
Water, salt, sugar, hydrogen, carbon
Seawater, sugar water, atmosphere

50. Chemical change
A change in which one or more substances are converted into different substance
Heat and light are evidence of chemical change

51. Properties of compounds
Different properties than their component elements
Due to a CHEMICAL CHANGE, the resulting compound has new and different properties:
Table sugar – carbon, hydrogen, oxygen
Sodium chloride – sodium, chlorine
Water – hydrogen, oxygen

52. Classification of Matter

53. Symbols and formulas Currently 117 elements
Elements have a 1 or 2 letter symbol and compounds have a formula*
Thus formula is made up of more than one symbol
Symbol can be the same – O2

54. Symbols and formulas Elements first letter is always capitalized
If there is a second letter it is always lowercase B Ba C Ca

55. Elements Start looking at element names Table B.7 on page R53
Page 52 Table 2.2 states a few

57. assessment
Classify each of these samples of matter as an element, a compound, or a mixture:
Table sugar
Cough syrup
Tap water
Nitrogen

58. Assessment
What elements make up the pain reliever acetaminophen, chemical formula C8H9O2N?
Which element is present in the greatest proportion by number of particles?

59. Chemical reactions

60. objectives Describe what happens during a chemical change
Identify 4 possible clues that a chemical change has taken place
Apply the law of conservation of mass to chemical reactions

61. Key Concepts What always happens duringa chemical change?*
What are four possible clues that a chemical change has taken place?*
How are the mass of the reactants and the mass of the products of a chemical reaction related?*

62. Chemical property
Ability of substance to undergo a specific chemical change
Iron + oxygen = rust
Rust is chemical property of iron
Once again, during a chemical change the composition of matter always changes*

63. Chemical reaction One or more substances changes into a new substance
2H2 + O2  2H2O
Reactants – what you start with
Products – what you make
Have different properties than reactants

64. Recognizing chemical changes
Energy – either absorbed or released as heat
Color change
Gas production – bubbling, fizzing, smoke or odor change
Precipitate formation – solid that separates from solution (won’t dissolve)
Irreversibility***

65. Check point
What energy transfer takes place when food cooks?

66. Conservation of mass During a chemical reaction
mass of products = mass of reactants*
All mass is accounted for:
Burning of wood results in products that appear to have less mass as ashes; where is the rest?
Carbon dioxide
Water vapor

67. assessment
What is the different between physical changes and chemical changes?

68. Assessment
Classify the following changes as physical or chemical changes
Water boils
Milk turns sour
Salt dissolves in water
A metal rusts

69. assessment
Hydrogen and oxygen react chemically to form water. How much water would form if 4.8 grams of hydrogen reacted with grams of oxygen?