1. Introduction to Chemistry Matter and Change
Chapters 1 & 2

2. What is Chemistry?
The study of matter, its properties and the changes it underdoes
What is Matter?
Anything that has mass and takes up space

3. What is Mass?
The amount of matter an object contains
What is Volume?
The amount of space occupied by matter

4. Why Study Chemistry? Helps us better understand nature
Helps us understand how things work (cleaning products, pharmaceuticals, shampoos, biology)
Can improve quality of life (plastics, permanent press, recycling processes, medical treatments)
Develops critical thinking skills, analytical skills, skills to organize and manage information

5. Fields of Chemistry
Organic
Analytical
Physical
Inorganic
Polymer
Medicinal
Environmental
Biochemistry

6. How We Study Chemistry Collect data (observations, measurements)
Analyze data (tables, graphs, calculations)
Interpret & Explain data
Draw conclusions
Evaluate data
Design new experiments
Understand and evaluate what others have done
Develop models and theories
Identify laws

7. Scientific Method
Questions/Observations
Hypothesis
Design Experiment
Collect Data
Analyze Data
Revise Hypothesis

8. Theories and Laws
Theory
Well-tested explanation for a broad set of observations
Law
A statement that summarizes observations but does not explain them

9. What is a Model?
A representation
May or may not be to scale
May represent something very large or something very small
Models take many forms… a diagram, a graph, a physical model
Used to help explain a concept

10. Characteristics of States of Matter
Property
Solid
Liquid
Gas
Mass
Shape
Volume
Compressible?
Effect of Temp on Expansion

11. Characteristics of States of Matter
Property
Solid
Liquid
Gas
Mass
Definite
Shape
Indefinite
Volume
Compressible? No
Yes
Effect of Temp on Expansion
Slight
Moderate
Large

12. Molecular Representation of States of Matter

13. How we describe matter
Substance
A sample of matter having a constant (uniform or definite) composition. It can be either an element or a compound.

14. How we describe matter
Element
A substance that cannot be decomposed into simpler substances by chemical or physical means. It consists of atoms having the same atomic number.

15. How we describe matter
Compound
A substance with constant composition that can be broken down into elements by chemical processes.

16. How we describe matter
Allotrope
Different forms of the same element
Example:
Carbon: diamond, graphite, buckyballs
Phosphorus: red, white, black

18. Allotropes of Phosphorus
White phosphorus can be transformed to red, black or violet by in creasing temperature or pressure
By Weißer_Phosphor.JPG: BXXXD at de.wikipedia Phosphor_rot.jpg: Tomihahndorf Phosphor-rot-violett.jpg: Maksim derivative work: Materialscientist [GFDL ( or CC-BY-SA-3.0 ( via Wikimedia Commons

19. How we describe matter - Particles
Atom
Smallest particle of an element that retains the properties of that element; the fundamental unit of which elements are composed

20. How we describe matter - Particles
Molecule
A bonded collection of two or more atoms of the same element or different elements. A representative particle of a molecular compound.
Examples:
Br2, CH4, H2O

21. Properties of Matter
Extensive property
Depends upon the amount of matter in a sample
Examples – mass, volume
Intensive property
Depends upon the type of matter, not the amount
Example – density, absorbancy

22. Properties of Matter
Physical Property
A quality or condition of a substance that can be observed or measured without changing the substance’s composition

23. Examples of Physical Properties
Density
State
Boiling Point
Solubility
Melting Point
Ductility
Color
Malleability
Odor
Conductivity
Luster
Hardness

24. Properties of Matter
Chemical Property
Ability to form new substances

25. Examples of Chemical Properties
Reactivity – reacts, neutralizes
Flammability – burns
Note: The fact that a substance does NOT react is a chemical property

26. Physical or Chemical Property?
Water melts at 0oC
Propane burns in air
Leaves turn color in the fall
Lead is a very dense metal

27. Physical and Chemical Changes
Physical Change
A change in the physical form of a substance but not its chemical composition;
Chemical bonds are not broken

28. Physical and Chemical Changes
The change of one substance into another substance through a reorganization of the atoms by breaking or making of chemical bonds;
A chemical reaction

29. Indicators of Chemical Change
Unexpected color change
Formation of a precipitate
Evolution of a gas
Change in energy

30. Differentiating Between Physical or Chemical Change
Physical change does not alter the composition of a substance though it may alter the appearance of the substance
Key words
Bend Boil
Break Melt
Crush Solidify
Dissolve Evaporate

31. Differentiating Between Physical or Chemical Change
Examples Salt dissolves in water. Solubility is a physical property so the change is physical. A liquid boils and is converted from a liquid to a gas. Boiling point is a physical property. A change in state is a physical change.

32. Molecular Description of Change in State

33. Differentiating Between Physical or Chemical Change
Chemical change produces a different substance; composition and properties are different. Requires a chemical reaction to reclaim the starting material. Not always easily done! Reactants  Products

34. Differentiating Between Physical or Chemical Change
Key words that indicate a chemical change: Reacts Precipitates Burn s Explodes Bubbles Emits Fizzes A flame Gives off

35. Differentiating Between Physical or Chemical Change
Examples
A match lights when struck
Substances are combined and light is emitted
An antacid tablet fizzes when added to water

36. How to differentiate between physical and chemical change
Physical change does not alter the composition of a substance although it may alter its appearance
Chemical change produces a different substance

37. Mixture
A combination of two or more substances that are not chemically combined. The components of the mixture is variable (can be made up differently at different times).

38. Types of Mixtures
Homogeneous Mixture:
Completely uniform in composition
Components are not distinguishable
A solution

39. Homogeneous Mixtures
Examples:
Salt water
Stainless steel
Sugar in water
Gasoline
Brass
Clean air
Jello

40. Composition of Common Alloys – Solid Solutions
14 K Gold
39 % Gold
25% Silver
39% Copper
Sterling Silver
93% Silver
7% Copper
Coinage Silver
90% Silver
10 % Copper
Pewter
85% Tin
6% Bismuth
5% Antimony
Cast Iron
96% Iron
4% Carbon

41. Types of Mixtures
Heterogeneous Mixture:
Not uniform in composition
Components are readily distinguishable
Different composition in different parts of the mixture

42. Heterogeneous Mixtures
Examples:
Tossed salad
Soil
Granite

43. Mixture lingo
Phase Any part of a system with uniform composition and properties. Homogeneous mixtures consist of one phase Heterogeneous mixtures consist of two or more phases (e.g., vinegar and oil)

44. Classification of Matter
Differentiate whether a sample is a substance (element or compound) or a mixture (homogeneous or heterogeneous)

45. Separation of Mixtures
Mixtures of substances can be separated by physical means. The mixtures may be homogeneous or heterogeneous. One or more processes may be required to separate mixtures.
Make use of type of mixture and physical properties of its components to select the best means of separation.

46. Techniques for Separation of Mixtures
Filtration
Evaporation
Extraction
Chromatography
Distillation
Decantation
Sieve
Magnet
Centrifuge
Forceps

47. Examples
Water and salt
Water and ethanol
Salt and sand
Sand and wood chips

48. How are physical & chemical properties used?
Identification
Reactivity
Separation of mixtures
State of substance under certain conditions

49. Physical Properties of Some Common Substances
Formula
State
Color
Melting Point
(oC)
Boiling Point
Density
(g/cm3)
Neon Ne
Gas
Colorless
-249
-246
0.0009
Oxygen O2
-218
-183
0.0014
Ethanol
C2H5OH
Liquid
-117 78
0.789
Chlorine
Cl2
Greenish-yellow
-101
-34
0.0032
Mercury Hg
Silvery white
-39
357
13.5
Bromine
Br2
Red-brown -7 59
3.12
Water
H2O
100
13.00
Sulfur S
Solid
Yellow
113
445
2.07
Sucrose
C12H22O11
White
185 d*
1.59
Sodium chloride
NaCl
801
1413
2.17
d, decomposes on heating.

50. Changes in State

51. Given physical properties and current temperature, what is the state of the substance?BP
SOLID
LIQUID
GAS
Increasing Temperature

52. If temperature is 45 oC, what is state of water? (liquid)
Water: mp = 0 oC, bp = 100 oC
If temperature is 45 oC, what is state of water?
(liquid)
If temperature is -29 oC, what is state of water?
(solid)
If temperature is 150 oC, what is state of water?
(gas)

53. Bromine: mp = -7 oC, bp = 59 oC
If temperature is -59 oC, what is state of bromine?
(solid)
If temperature is 28 oC, what is state of bromine?
(liquid)
If temperature is 83 oC, what is state of water?
(gas)

54. Symbols and Formulas
Element or chemical symbols
Al = Aluminum
C = Carbon
Pb = Lead
Many symbols based on Latin or German names