1. Chapter 2
Matter & Change

2. Describing Matter Matter Anything that takes up space and has mass
A pure substance or as a matter of substances
Properties used to describe matter can be classified as extensive or intensive
Extensive Property
Depends on the amount of matter in a sample
Intensive Property
Depends on the type of matter in a sample (i.e. hardness)

3. Extensive Property Mass
A measure of the amount of matter the object contains
Volume
A measure of the space occupied by the object

4. States of Matter
Three states of matter are: solid, liquid, and gas.

5. Solid Matter that has definite shape and volume
Particles are tightly packed together (not easily compressed)

6. Liquid
Matter that flows, has a fixed volume, and takes the shape of its container
Particles are packed less tightly than in a solid (not easily compressed)

7. Gas (Vapor) matter that has no definite shape or volume
It takes the shape of its container and can be compressed
Particles in a gas are spaced far apart (easily compressed)

8. Sample Exercise
What is the physical state of each of the following at room temperature?
Gold
Gasoline
Helium

9. Physical Changes
The shape of a sample changes, but the composition stays the same
Boil, freeze, melt, condense, break, split, grind, cut, and crush.
Physical changes can be reversible or irreversible

10. Section Assessment In what way are liquids and gases alike?
In what way are liquids and solids different?
Is the freezing of mercury (Hg) a reversible or irreversible physical change?

11. Classifying Mixtures
Consists of a physical blend of two or more substances
Can be classified as heterogeneous mixtures or as homogenous mixtures

12. Heterogeneous mixture
not uniform in composition
Ex: salad, stew

13. 2. Homogeneous mixture A complete uniform composition
Ex: iced tea, lemonade
Also called a solution

14. Differences in physical properties can be used to separate mixtures
Distillation
A liquid is boiled to produce a vapor that is then condensed into a liquid
This process separates liquids by their boiling points (and impurities)
Separating Mixtures

15. Filtration
Separates a solid from the liquid in a heterogeneous mixture

16. Distillation
A liquid is boiled to produce a vapor that is then condensed into a liquid
This process separates liquids by their boiling points (and impurities)

18. Fermentation
Plums
Mashed Plums

19. Distiller

20. Plum Mash Poured into Distiller
Top View

21. Distiller Set Ablaze

23. Moonshine

24. 3. Chromatography – a technique that is used to physically separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material

25. Classify each of the following as a homogenous or heterogeneous mixture
Food coloring
Ice cubes in liquid water
Mouthwash
Mashed, unpeeled potatoes
Section Assessment

26. Section assessment
When would you use filtration to separate a mixture?
When would you use distillation to separate a mixture?

27. Elements Simplest forms of matter Cannot be broken down
Building blocks for all other substances
Ex: Periodic Table of Elements

28. Sodium (Na) Natrium

29. Chlorine (Cl)

30. Compounds
Contains two or more different elements chemically combined in a fixed proportion
Can be broken down into elements, by a chemical change
Ex: water, sodium chloride

31. Sodium Chloride (Table Salt)

32. Figure: 01-05a-d

33. Figure: 01-01

34. Distinguishing Substances and Mixtures
Beryl - Be3Al2(SiO3)6
Substance – if the composition of the material is fixed (elements, and compounds)
Distinguishing Substances and Mixtures

35. Mixture
If the composition of a material may vary
Various Granite

36. Practice Problems
Liquid A and Liquid B are clear liquids. They are placed in open containers and allowed to evaporate. When evaporation is complete, there is a white solid in container B, but no solid in container A. From these results, what can you infer about the two liquids?

37. Practice Problems
A clear liquid in an open container is allowed to evaporate. After three days, a solid is left in the container. Was the clear liquid an element, a compound, or a mixture? How do you know?

38. Symbols and Formulas
Chemists use chemical symbols to represent elements, and chemical formulas to represent compounds.

39. Chemical Symbol Each element is represented by a one or two letters
The first letter is always capitalized
When a second letter is used, it is lowercase
Chemical formulas are used to represent compounds: CO2

40. Section Assessment Write the chemical symbol for each element Lead
Oxygen
Silver
Sodium
Hydrogen
Aluminum

41. Section assessment
Name the chemical elements represented by the following symbols C Ca K Au Fe Cu

42. Chemical Change
Change that produces matter with a different composition than the original matter
Usually involves burning, rotting, decomposing, fermenting, exploding, rusting, corroding.
Ex: milk spoils, electrolysis of water

43. Figure: 01-10

44. Chemical Reactions Chemical Property
The ability of a substance to undergo a specific chemical change
During a chemical change, the composition of matter always changes
A substance that is present at the start of the reaction is a reactant
A substance produced in the reaction is a product

45. Recognizing Chemical Changes
Possible clues to a chemical change include:
A transfer of energy
A change in color
The production of a gas
The formation of a precipitate
Precipitate (ppt)
A solid that forms and settles out of a liquid mixture, and is usually indicated by a color change

46. A transfer of energy

47. A change in color (precipitate)

48. The production of a gas

49. Conservation of Mass
During any chemical reaction, the mass of the products is always equal to the mass of the reactants
Mass is conserved
Mass is neither created nor destroyed

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

52. Section Assessment
Hydrogen and oxygen react chemically to form water. How much water would form if 4.8 grams of hydrogen reacted with 38.4 grams of oxygen?
2H2 + O2  2H2O

53. Section Assessment
When ammonium nitrate (NH4NO3) explodes, the products are nitrogen, oxygen, and water. When 40 grams if ammonia nitrate explode 14 grams of nitrogen and 8 grams of oxygen form. How many grams of water form?
NH4NO3  N2 + O2 + H2O

54. Key Concepts - Properties of Matter
Properties used to describe matter can be classified as extensive or intensive
Every sample of a given substance has identical intensive properties because every sample has the same composition
Three states of matter are solid, liquid, and gas
Physical changes can be classified as reversible or irreversible

55. Key Concepts - Mixtures
Mixtures can be classified as heterogeneous mixtures or as homogeneous mixtures, based on the distribution of their components
Difference in physical properties can be used to separate mixtures

56. Key Concepts – Elements and Compounds
Compounds can be broken down into simpler substances by chemical means, but elements cannot
If the composition of a material is fixed, the material is a substance. If the composition may vary, the material is a mixture
Chemists use chemical symbols to represent elements, and chemical formulas to represent compounds
Key Concepts – Elements and Compounds

57. Key Concepts – Chemical Reactions
During a chemical change, the composition of matter always changes
Four possible clues to chemical change include a transfer of energy, a change in color, the production of a gas, or the formation of a precipitate
During any chemical reaction, the mass of the products is always equal to the mass of the reactants