1. Zumdahl • Zumdahl • DeCoste
World of
CHEMISTRY

2. Chapter 2
Matter

3. 2.1 The Particualte Nature of Matter
Objective: To Learn about the composition of matter.
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4. Matter, the “stuff” the universe is made of.
Two Characteristics:
Mass
Occupies Space
Examples
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5. The Atomic Nature of Matter
All matter consists of tiny particles called ATOMS.
Consider a painting by George Seurat:
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9. Although objects in the macroscopic world appear continuous and uniform, they are really particulate in nature, i.e. they are composed of atoms.
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10. 2.2 Elements and Compounds
Objectives: To Learn the difference between elements and compounds.
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11. All Atoms Are Not Equal
All matter is composed of about 100 different atoms.
Example –
the air we breath is composed of: 80% Nitrogen (N2) and approx. 20% Oxygen (O2).
Words in a book are composed of different arrangements of our 26 letter alphabet.
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12. Compounds
Compounds are substances made by bonding atoms together in specific ways. They are composed of different atoms, configured (arranged) in the same way.
Example: H2O - Water
Contains 2 Hydrogen atoms (H2) and 1 Oxygen atom (O). O
H H
CO2 another compound (dry ice) composed of molecules of O=C=O
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13. Molecules Molecules are made up of atoms that are ‘stuck’ together.
A glass of water contains lots of molecules that are closely stuck together.
Steel is composed of iron (Fe) Carbon (C) and various other atoms depending on how it will be used (e.g. Chromium (Cr) and Nickel(Ni) are used for stainless steel).
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14. Atom Combinations
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15. Elements Elements are substances that contain only one type of atom.
A sample of Lead (Pb) contains may atoms but they are all the same.
Some pure elements do contain molecules: e.g. Hydrogen H H (H2)
A Compound always contains different atoms.
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16. Top Ten
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17. Figure 2.5: The three forms of the element carbon: Diamond.
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18. Figure 2.5: The three forms of the element carbon: Graphite.
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19. Figure 2.5: The three forms of the element carbon: Buckminsterfullerene.
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20. Objectives: To define the three states of matter.
2.3.The States of Matter
Objectives: To define the three states of matter.
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21. 3 States of Matter Solid Liquid Gas
Each state of matter changes the properties of a molecule.
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22. Characteristics of the 3 States of Matter for Water
Solid
Less dense (ice floats)
Increased strength (ice-skaters)
Liquid
Allows for diffusion
Takes the shape of the container
Gas
Invisible to the naked eye

23. Solid Liquid Gas Rigid Fixed Shape and Volume Definite volume
Takes the shape of the container
Liquid
No defined shape
No fixed volume
Gas

24. Focus Questions How do atoms, compounds, and elements differ?
How do elements differ from compounds? (consider the letters in the word ‘chemistry’)
Describe the differences between a solid, liquid and a gas.
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25. 2.4 Physical and Chemical Properties of Change
Objectives:
To learn to distinguish between physical and chemical properties.
To learn to distinguish between physical and chemical changes
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26. Physical Properties
A Physical Property is a characteristic that we use to recognize a particular substance:
Odor
Color
Volume
State (liquid, solid or gas)
Density
Melting/boiling point
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27. Chemical Properties
Chemical properties refer the ability of a pure substance to form new substances:
Wood burning → Heat + CO2 (g) + Ashes (s)
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28. Example 2.1 Identifying Physical and Chemical Properties
Physical or Chemical?
Gallium Metal Melts in your hand.
Platinum does not react with oxygen at room temperature.
This page is blue.
The copper sheets that form the “skin” of the Statue of Liberty have acquired a greenish coating over the years.
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29. Physical and Chemical Changes of Matter
Solid
Liquid
Gas
Melting
Boiling
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30. Figure 2.7: The three states of water: Solid.
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31. Figure 2.7: The three states of water: Water.
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32. Figure 2.7: The three states of water: Gas.
During all of these phase changes, the water molecule (H2O) stays bonded. The motions/distance of the individual molecules changes, i.e. the changes are “physical changes”.
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33. Figure 2.8: Electrolysis, the decomposition of water by an electric current, is a chemical process.
Exposure to an electrical current produces a “chemical” change.
2H2O → 2H2 +O2 molecules
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34. Summarizing It All
Physical Changes involve one or more physical properties change (Odor, Color, Volume, State (liquid, solid or gas),Density, and Melting/boiling point.
Chemical changes involves a change in the components of the substance, i.e. a given substance changes (reacts) to create a different substance.
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35. Example 2.2 Self Check
Chemical or Physical? 1. Milk Turns Sour. 2. Wax is melted over a flame and then catches fire and burns.
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36. 2.5 Mixtures and Pure Substances
Objectives: To learn to distinguish between mixtures and pure substances.
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37. Mixtures
A Mixture can be defined as something that has variable composition.
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38. Figure 2.9: The composition of air.
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39. Chart examining each substance of air.
The composition
of mixtures varies;
the atomic composition of compounds always remains the same.

40. Figure 2. 10: Twenty-four-karat gold is an element
Figure 2.10: Twenty-four-karat gold is an element. Eighteen-karat gold is an alloy. Fourteen-karat gold is an alloy.
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41. Figure 2.11: Representation of H2O molecules.
Compound or Mixture?
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42. Pure Substances A Pure Substance always has the same composition.
i.e they are either elements or compounds.
Mixtures can be separated into pure substances .
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43. Homogenous and Heterogenous Mixtures
Homogenous Mixtures is the same throughout. It is also called a Solution.
Example: Table salt mixed with water.
The composition is equally distributed throughout the entire solution.
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44. Homogenous and Heterogeneous Mixtures
A Heterogeneous mixture contains regions that have different properties from those of other regions.
Example: sand and water
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45. Example 2.3 Self Check
Classify each of the following as Pure, Homogeneous, or heterogeneous>
Maple syrup
The oxygen and helium in a scuba tank
Oil and vinegar salad dressing
Common salt (NaCl sodium chloride)
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46. 2.6 Separations of Mixtures
Objectives: To learn two methods of separating mixtures.
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47. Figure 2.14: The solution is boiled and steam is driven off.
Distillation
Liquid →Gas →Liquid
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48. Figure 2.14: Salt remains after all water is boiled off.
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49. Figure 2.15: No chemical change occurs when salt water is distilled.
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50. Figure 2.16: Filtration separates a liquid from a solid.
Filtration separates heterogeneous
Mixtures.
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51. Figure 2.17: Separation of a sand-saltwater mixture.
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52. Figure 2.18: The organization of matter.
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53. Setup to boil water.
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