1. Atoms, Molecules, and the States of Matter Chapter 1

2. Universe Classified
Matter is the part of the universe that has mass and volume
Energy is the part of the universe that has the ability to do work
Chemistry is the study of matter
The properties of different types of matter
The way matter behaves when influenced by other matter and/or energy 3

3. Elements and Compounds
Substances which can not be broken down into simpler substances by chemical reactions are called elements
Most substances are chemical combinations of elements. These are called compounds.
Compounds are made of elements
Compounds can be broken down into elements
Properties of the compound not related to the properties of the elements that compose it
Same chemical composition at all times 11

4. Elements Over 112 known, of which 88 are found in nature
others are man-made
Abundance is the percentage found in nature
oxygen most abundant element (by mass) on earth and in the human body
the abundance and form of an element varies in different parts of the environment
Each element has a unique symbol
The symbol of an element may be one letter or two
if two letters, the second is lower case 2

6. The periodic table

7. Distribution (Mass Percent) of the 18 Most Abundant Elements in the Earth's Crust, Oceans, and Atmosphere

8. Abundance of elements in the human body

9. Metallic Character Metals Metalloids Nonmetals malleable & ductile
shiny, lustrous
conduct heat and electricity
most oxides basic and ionic
form cations in solution
lose electrons in reactions - oxidized
Metalloids
Also known as semi-metals
Show some metal and some nonmetal properties
Nonmetals
brittle in solid state
dull
electrical and thermal insulators
most oxides are acidic and molecular
form anions and polyatomic anions
gain electrons in reactions - reduced 22

10. The classification of elements as metals, nonmetals, and metalloids

11. Dalton’s Atomic Theory
Elements are composed of atoms
tiny, hard, unbreakable, spheres
All atoms of a given element are identical
all carbon atoms have the same chemical and physical properties
Atoms of a given element are different from those of any other element
carbon atoms have different chemical and physical properties than sulfur atoms 3

12. Dalton’s Atomic Theory
Atoms of one element combine with atoms of other elements to form compounds.
Atoms are indivisible in a chemical process.
all atoms present at beginning are present at the end
atoms are not created or destroyed, just rearranged
atoms of one element cannot change into atoms of another element 4

13. Elements and Compounds
Substances which can not be broken down into simpler substances by chemical reactions are called elements
Most substances are chemical combinations of elements. These are called compounds.
Compounds are made of elements
Compounds can be broken down into elements
Properties of the compound not related to the properties of the elements that compose it
Same chemical composition at all times

14. Formulas Describe Compounds
a compound is a distinct substance that is composed of atoms of two or more elements
describe the compound by describing the number and type of each atom in the simplest unit of the compound
molecules or ions
each element represented by its letter symbol
the number of atoms of each element is written to the right of the element as a subscript
if there is only one atom, the 1 subscript is not written 6

15. Dalton pictured compounds as collections of atmosphere NO, NO2, and N2O are represented

16. Classification of Matter
Homogeneous = uniform throughout, appears to be one thing
pure substances
solutions (homogeneous mixtures)
Heterogeneous = non-uniform, contains regions with different properties than other regions 12

17. Pure Substances vs. Mixtures
All samples have the same physical and chemical properties
Constant Composition  all samples have the same composition
Homogeneous
Separate into components based on chemical properties
Mixtures
Different samples may show different properties
Variable composition
Homogeneous or Heterogeneous
Separate into components based on physical properties
All mixtures are made of pure substances 13

18. Table salt is stirred into water (left), forming a homogeneous mixture called a solution (right)

19. Sand and water do not mix to form a uniform mixture

20. Identify Each of the following as a Pure Substance, Homogeneous Mixture or Heterogeneous Mixture
Gasoline
a homogenous mixture
A stream with gravel on the bottom
a heterogeneous mixture
Copper metal
A pure substance (all elements are pure substances) 15

21. Colloids and Emulsions
Colloid = mixture of one finely divided material dispersed in another
Emulsions = colloids where both compounds are liquids; often commercially useful
Ice cream, mayonnaise
Emulsifying agent = helps keep two substances from separating (egg yolk keeps water and oil separate in mayonnaise)

22. The organization of matter

23. States of Matter
solid, liquid, gas 7

24. The three states of water

25. Changes in Matter
Physical Changes are changes to matter that do not result in a change of the fundamental components that make that substance
State Changes – boiling, melting, condensing
Chemical Changes involve a change in the fundamental components of the substance
Produce a new substance
Chemical reaction
Reactants  Products 8

26. Classify Each of the following as Physical or Chemical Changes
Iron is melted.
Physical change – describes a state change, but the material is still iron
Iron combines with oxygen to form rust.
Chemical change – describes how iron and oxygen react to make a new substance, rust
Sugar ferments to form ethyl alcohol.
Chemical change – describes how sugar forms a new substance (ethyl alcohol) 10

27. Kinetic - Molecular Theory
The properties of solids, liquids and gases can be explained based on the speed of the molecules and the attractive forces between molecules
In solids, the molecules have no translational freedom, they are held in place by strong attractive forces
May only vibrate 18

28. Solids amorphous solids crystalline solids show no definite structure
therefore strengths of intermolecular forces vary over the structure
glass, plastic, rubber
tend to soften and melt over a temperature range
crystalline solids
orderly, repeating, 3-dimensional pattern
pattern = crystal lattice
melt at one specific temperature 5

29. The arrangement of sodium ions (Na+) and chloride ions (Cl-) in the sodium chloride, NaCl.

30. Kinetic - Molecular Theory
In liquids, the molecules have some translational freedom, but not enough to escape their attraction for neighboring molecules
They can slide past one another, rotate as well as vibrate
In gases, the molecules have “complete” freedom from each other, they have enough energy to overcome “all” attractive forces 19

31. Describing a Gas Gases are composed of tiny particles
The particles are small compared to the average space between them
Assume the molecules do not have volume
Molecules constantly and rapidly moving in a straight line until they bump into each other or the wall
Average kinetic energy proportional to the temperature
Results in gas pressure
Assumed that the gas molecules attraction for each other is negligible 20

32. Gas Properties Explained
Gases have indefinite shape and volume because the freedom of the molecules allows them to move and fill the container they’re in
Gases are compressible and have low density because of the large spaces between the molecules 21

33. Gas Pressure Pressure = total force applied to a certain area
larger force = larger pressure
smaller area = larger pressure
Gas pressure caused by gas molecules colliding with container or surface
More forceful collisions or more frequent collisions mean higher gas pressure 3

34. The pressure exerted by the gases in the atmosphere can demonstrated by boiling water in a can

35. Liquid Crystals State of matter intermediate to solid and liquid
Only occurs for a few compounds, usually for molecules that are long and rod-shaped.
The ordered arrangement can be re-ordered by changing the liquid crystal’s environment
Numbers on a digital watch appear as a liquid crystal realigns due to electrical charge and becomes opaque

37. Metallic Mixtures
Alloys are mixtures of elements that show metallic properties
Substitutional Alloys have some host metal atoms replaced by metal atoms of similar size
Brass = Copper with Zinc substituted
Interstitial Alloys have small atoms occupying some of the holes in the crystal lattice of the host metal
Steel = Iron with Carbon added 24

38. Two types of alloys