1. Chemistry I Chapter 3 Matter Properties and Change

2. 1.)What is a pure substance?
Matter that has a uniform and unchanging composition

3. 2.)What is a physical property?
A characteristic that can be observed or measured without changing the composition of the substance.

4. Examples of physical properties include: density, color, odor, taste, hardness, melting point and boiling point

5. 3.)What are the two types of physical properties?
extensive and intensive

6. 4.)What are extensive properties?
Extensive properties are dependent on the amount of substance present.
i.e., length, volume, mass

7. 5.)What are intensive properties?
Intensive properties are independent of the amount of substance present.
i.e., density, melting point, boiling point

8. 6.)What type of physical property can be used to identify a pure substance?
Intensive properties

9. 7.What is a chemical property?
The ability of a substance to combine with or change into one or more substances. Also, the inability of a substance to change into another substance is a chemical property.

10. 8.)What are the four states of matter in order of increasing energy?
solid →liquid→gas →plasma

11. 9.)Describe the solid state
Definite shape and volume
Particles are tightly packed
incompressible

12. 10.)Describe the liquid state
Particles of matter can flow past one another.
Constant volume
Takes the shape of the container
incompressible

13. 11.)Describe the gas phase
Fills the entire volume of its container
Particles are far apart
Gases are compressible

14. 12.)Describe the plasma phase
Energy level is so high that intact atoms do not exist; protons and electrons are separated.
Most common phase in the universe, but is not common on earth.
Found in lightening strikes or in electrical sparks.

15. Changes in Matter

16. 13.)What are physical changes?
Changes that alter the appearance of a substance without changing its composition.
All changes of phase are physical changes.

17. 13.)What are physical changes?
*ice → water → steam
Still water (H2O)
*Nitrogen gas is cooled and become liquid nitrogen, but its still pure N2
*Crumpled aluminum foil is still aluminum

18. Examples of physical changes?
Melting, freezing, boiling, bending, grinding, crumpling, splitting, crushing

19. 14.)What are chemical changes?
A process that involves one or more substances changing into new substances.
Something new is formed.

20. 15.)What are some terms that imply that a chemical reaction has occurred?
Combust, rust, explode, corrode, tarnish, ferment, burn, decompose

21. 16.)What are some signs that a chemical reaction has occurred?
Evolution of a gas
Color change
Change of temperature
Formation of a precipitate
Change in magnetic properties

22. 17.)What is the Law of Conservation of Mass?
Mass is neither created nor destroyed during a chemical reaction. It is conserved.

23. What is the Law of Conservation of Mass?
For example
2HgO → 2 Hg O2
432g = g g
reactant products

24. Mixtures of Matter

25. 18.)What is a mixture?
A combination of two or more pure substances in which each pure substance retains its individual chemical properties

26. What is a mixture?
For example,
Stew – carrots, potatoes and beef
Air – oxygen, nitrogen, carbon dioxide and water vapor

27. 19.)What are the two classifications of mixtures?
1.) Heterogenous- does not blend smoothly, individual substances remain distinct.
Stew, concrete

28. What are the two classifications of mixtures?
2.) homogeneous- has a constant composition through ( the same)
Air, saline

29. 20.)What is another name for a homogeneous mixture?
A solution

30. 21.) Types of solutions
gas – gas: air
gas – liquid: CO2 in soda
liquid- gas: moist humid air
liquid – liquid: vinegar and water
solid- liquid: sugar water
solid – solid: steel

31. 22.)What are some methods that may be used to separate mixtures?
Filtration- uses a porous barrier to separate liquid and solid.
i.e., sand and water

32. 22.)What are some methods that may be used to separate mixtures?
Magnetic properties
Sulfur and iron filings

33. 22.)What are some methods that may be used to separate mixtures?
Distillation- a separation technique that is based on differences in boiling points
i.e., alcohol and water

34. 22.)What are some methods that may be used to separate mixtures?
Chromotography – a separation technique that separates the components of a mixture ( called the mobile phase) on the basis of the tendency of each to travel or be drawn across the surface of another (called the stationary phase)

35. 22.)What are some methods that may be used to separate mixtures?
Crystallization a separation technique that results in particles of a substance from a solution containing the dissolved substance.
Crystallization produces highly pure solids.

36. Elements and Compounds

37. 23.)What are the two subdivisions of all pure substances?
Elements and compounds

38. 24.) What is an element?
An element is a pure substance that cannot be separated into simpler means by chemical or physical means.

39. 25.)How many naturally occurring elements are there?91

40. 26.)What are the trans-uranium elements?
No elements past uranium are naturally occurring. These elements are unstable and must be made synthetically in the laboratory.

41. 27.)How are the elements represented by chemical symbols?
Most symbols are 1 or 2 letters. The first letter must be capitol, the second must be lower case.

42. 28.)What is the periodic table?
The periodic table organizes the elements into a grid of horizontal rows and vertical columns based on chemical and physical similarities and trends.

43. 29.)What do we call the vertical columns?
The columns are called groups or families.

44. 30.)What is significant about the elements in the same family or group?
These elements have similar properties.

45. 31.)Who is credited with designing the first periodic table?
The Russian chemist/professor
Dmitri Mendeleev

46. 32.)What is significant about the empty spaces that Mendeleev left on his original periodic table?
Mendeleev left empty spaces for elements he believed had yet to be discovered. He predicted the properties of these elements before they were discovered.

47. 32 contd. What is significant about the empty spaces that Mendeleev left on his original periodic table?
When the discovered elements matched the predicted properties, it gave support for the periodic table as a valid tool.

48. 33.)What is a compound?
A combination of two or more different elements that are chemically combined.
A compound can be broken down into simpler substances by chemical or physical means.

49. 34.) How are chemical symbols used to indicate the number of atoms of each element?
The symbol is written 1st . The # of atoms of each element is written as a subscript after the symbol. If only one atom is present the 1 is not written.

50. 34 contd. How are chemical symbols used to indicate the number of atoms of each element?
CO2 1 carbon;2 oxygen

51. 34 contd.How are chemical symbols used to indicate the number of atoms of each element?
If parenthesis are used, the subscript after the parenthesis applies only to the elements in the parenthesis.

52. 34 contd. How are chemical symbols used to indicate the number of atoms of each element?
Ca(NO3)2 1 calcium; 2 nitrogen; 6 oxygen
Ca3(PO4)2 3 calcium; 2 phosphorus; 8 oxygen

53. 35.) How do the properties of a compound compare to the elements that make it up?
They are very different.
H2O liquid water at room temp.
H2 gas at room temp.
O2 gas at room temp.

54. 36.) What are two ways that a compound can be broken down into simpler substances by physical means.
Electrolysis (passing an electric current through the substance) and heating it.

55. 37.) What is the classification diagram of all matter?

56. 38.)What is the Law of Definite Proportions?
Regardless of the amount, a compound is always composed of the same elements in the same proportions by mass.

57. 39.)How do you find % mass? % mass = mass of element x 100
mass of compound

58. Sucrose analysis – 20 gram sample
Column 1
Column 2
Element
Analysis by mass(g)
% by mass
carbon
8.44 g
8.44/20.0 x 100 = 42.2 %
hydrogen
1.30 g
1.30/20.0 x 100 = 6.50%
oxygen
10.26 g
10.26/20.0 x 100 = 51.30%
total
20.0 g
100.0 %

59. Sucrose analysis – 500 gram sample
Column 1
Column 2
Element
Analysis by mass(g)
% by mass
carbon
211.0 g
211.0/500.0 x 100 = 42.2 %
hydrogen
32.5 g
32.5/500.0 x 100 = 6.50%
oxygen
256.6 g
256.6/500.0 x 100 = 51.30%
total
500.0 g
100.0 %

60. 40.)What is the Law of Multiple Proportions?
When different compounds are formed by a combination of the same elements,different masses of one element combine with the same relative mass of the other.

61. For example, compare water H2Oand peroxide H2O2.
Compare masses
H2O 2 amu: 16 amu
11%: 89%
H2O2 2 amu; 32 amu
0.06%: 94%

62. 41.) What formula is used to show the Law of Multiple Proportions?
Mass ratio of compound I
Mass ratio of compound II
11/89 = = 2
.06/

63. For example, compare water H2Oand peroxide H2O2.
Mass ratio of compound I
Mass ratio of compound II
11/89 = = 2
.06/

64. Law of Multiple Proportions example
Compound
% Cu
% Cl
Mass Cu (g) in 100g
Mass Cl (g) in 100g
Mass ratio mass Cu
Mass Cl I
64.20
35.80
1.793 II
47.27
52.73
.08964

65. Law of Multiple Proportions example

66. Mass ratio compound I = 1.793 = 2
Mass ratio compound II