1. Chapter 2
Properties of Matter

2. Matter anything that has mass and volume
Mass: measure of the amount of matter an object contains
Volume: measure of space occupied by the object

3. Matter Every sample of matter is Pure Substance Mixture
Element or Compound
Mixture
Homogeneous or Heterogeneous

4. Matter

5. Elements
A substance that cannot be broken down into simpler substances by chemical means
Elements are made up of one type of atom
Atom: smallest unit of matter that keeps its chemical properties

6. Elements
Elements are represented by an element symbol

7. Molecules Smallest unit of a substance that behaves like the substance
Chemically bonded together

8. Compounds A substance made up of atoms of different elements.
Contains 2 or more elements
Chemically combined
Definite proportions
Elements combine in the same proportions
Ex: water, H2O
hydrogen peroxide, H2O2

9. Chemical Formula Represent compounds C12H22O11 table sugar
3 molecules of table sugar (3C12H22O11) are equivalent to
___Carbons
___Hydrogens
___ Oxygens

10. Pure substances and Mixtures
All matter is either a pure substance or a mixture
Pure substance
Compound or Element
Mixture
Heterogeneous or Homogenous

11. Pure substance Element or Compound
Matter that has fixed composition and definite properties
Table Salt (NaCl – sodium chloride)

12. Mixtures Physical blend of 2 or more compounds
Heterogeneous: composition is not uniform throughout (2 or more phases)
Homogeneous: composition is uniform throughout (1phase)
aka: solution
Phase: any part of a sample with uniform composition

13. Properties of Matter Extensive: depends on amount of matter
Ex: volume, mass
Intensive: depends on type of matter
Ex: density, m.p., hardness

14. Properties of Matter
Physical property: properties that can be observed or measured without changing substance’s composition
They help identify substances
They can be observed or measured mass or volume
They also help determine uses- socks-clean/dirty, matching clothes-color
Can you think of other physical properties that help us determine how can use a substance?

15. Properties of Matter
Chemical property: ability of substance to undergo a specific chemical change
Flammability, reactivity, etc.
Gold vs. Copper

16. Density is a physical property = Mass per Volume
Grams/cubic centimeter (g/cm3)
Grams/ milliliter (g/ml)
D= mass
volume

17. Classification of Matter

18. Physical Changes
Some properties of a material change, but the composition of the material does not change
Reversible: Boil, freeze, melt, condense
Irreversible: Break, split, grind, cut, crush

19. Physical Changes
Affects one or more physical properties – does not change the identity
Composition of substance remains unchanged
Reversible: melt, freeze, sublime, etc
Irreversible: cut, crack, chip, etc

20. Chemical Changes A complete new substance is formed
Reversible/Irreversible
Burn, rot, rust, decompose, ferment, explode, corrode, grow

21. Chemical Change
A change in which one or more substances are converted into different substances.
Heat and light are often evidence of a chemical change.

22. Separating Mixtures
Physical means: rocks and marbles, iron filings and sulfur (use magnet)
Differences in physical properties can be used to separate mixtures.
Magnetic, temperature, etc.
Filtration - separates a solid from the liquid in a heterogeneous mixture (by size)
Distillation – liquid boiled to produce a vapor that is condensed into a liquid

23. Separation of a Mixture
Distillation: takes advantage of different boiling points.
NaCl boils at 1415 oC

24. Separation of a Mixture
Paper chromatography - Components of dyes such as ink may be separated

25. States of Matter Solid: def shape, def volume
Liquid: indef shape, def volume
Gas: indef shape, indef volume
Easily compressed
Vapor: the gaseous state of a substance that is generally a liquid

26. Three Main Phases – page 41

27. States of Matter Definite Volume? Definite Shape? Solid Liquid Gas
Result of a TemperatureIncrease?
Definite Volume?
Definite Shape?
Will it Compress?
Small Expans.
Solid
YES
YES NO
Small Expans.
Liquid NO NO
YES
Large Expans.
Gas NO NO
YES

28. Condense
Freeze
Melt
Evaporate
Solid
Liquid
Gas

29. Substances: Element or Compound
Elements- simplest kind of matter
cannot be broken down any simpler and still have properties of that element!
all one kind of atom.
Compounds are substances that can be broken down only by chemical methods
when broken down, the pieces have completely different properties than the original compound.
made of two or more atoms, chemically combined (not just a physical blend!)

30. Elements vs. Compounds
Compounds can be broken down into simpler substances by chemical means, but elements cannot.
A “chemical change” is a change that produces matter with a different composition than the original matter.

31. Compound vs. Mixture Compound Mixture Made of one kind of material
Made of more than
one kind of material
Made by a
chemical change
physical change
Definite
composition
Variable

32. Which is it?
Mixture
Compound
Element

33. Volume is:
A measure of the space occupied by the object

34. Describing Matter
Properties used to describe matter can be classified as:
Extensive – depends on the amount of matter in the sample
- Mass, volume, length are examples
Intensive – depends on the type of matter, not the amount present
- Hardness, Density, Boiling Point

35. Properties are… Words that describe matter (adjectives)
Physical Properties- a property that can be observed and measured without changing the material’s composition.
Examples- color, hardness, m.p., b.p.
Chemical Properties- a property that can only be observed by changing the composition of the material.
Examples- ability to burn, decompose, ferment, react with, etc.

36. States of matter
Solid- matter that can not flow (definite shape) and has definite volume.
Liquid- definite volume but takes the shape of its container (flows).
Gas- a substance without definite volume or shape and can flow.
Vapor- a substance that is currently a gas, but normally is a liquid or solid at room temperature. (Which is correct: “water gas”, or “water vapor”?)

37. 4th state: Plasma - formed at high temperatures; ionized phase of matter as found in the sun

38. Copper Phases - Solid

39. Copper Phases - Liquid

40. Copper Phases – Vapor (gas)

41. Physical vs. Chemical Change
Physical change will change the visible appearance, without changing the composition of the material.
Boil, melt, cut, bend, split, crack
Is boiled water still water?
Can be reversible, or irreversible
Chemical change - a change where a new form of matter is formed.
Rust, burn, decompose, ferment

42. MIXTURES
Mixtures are a physical blend of at least two substances; have variable composition. They can be either:
Heterogeneous – the mixture is not uniform in composition
Chocolate chip cookie, gravel, soil.
Homogeneous - same composition throughout; called “solutions”
Kool-aid, air, salt water
Every part keeps it’s own properties.

43. Solutions are homogeneous mixtures
Mixed molecule by molecule, thus too small to see the different parts
Can occur between any state of matter: gas in gas; liquid in gas; gas in liquid; solid in liquid; solid in solid (alloys), etc.
Thus, based on the distribution of their components, mixtures are called homogeneous or heterogeneous.

44. Phase?
The term “phase” is used to describe any part of a sample with uniform composition of properties.
A homogeneous mixture consists of a single phase
A heterogeneous mixture consists of two or more phases.
Note Figure 2.6, page 45

45. Section 2.3 Elements and Compounds
OBJECTIVES:
Explain the differences between an element and a compound.

46. Section 2.3 Elements and Compounds
OBJECTIVES:
Distinguish between a substance and a mixture.

47. Section 2.3 Elements and Compounds
OBJECTIVES:
Identify the chemical symbols of elements, and name elements given their symbols.

48. Properties of Compounds
Quite 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

49. Symbols & Formulas
Currently, there are 117 elements
Elements have a 1 or two letter symbol, and compounds have a formula.
An element’s first letter always capitalized; if there is a second letter, it is written lowercase: B, Ba, C, Ca, H, He
Start learning the elements names and symbols listed in Table B.7 on page R53
Some names come from Latin or other languages; note Table 2.2, page 52

50. Section 2.4 Chemical Reactions
OBJECTIVES:
Describe what happens during a chemical change.