Chemistry 101 Final Exam Study Guide Part 1

Chemistry
– The study of chemicals and their chemical reactions.
Scientific Method
Steps:
– Observations
– Hypothesis; the problem to solve
– Experiment; designed to test hypothesis
– Data; collection of data to draw conclusions
– Reformulate hypothesis
Basic Units
– Weight/mass = Grams
– Volume = Liters
– Length = Meters
Weight Units
– 1,000 grams = 1 kilogram
– 1,000 milligrams = 1 gram
– 454 grams = 1 pound
Volume Units
– 1,000 liters = 1 kiloliter
– 1,000 milliliters = 1 liter
– 1 milliliter = 1 centimeter ^3
Length Units
– 1,000 meters = 1 kilometer
– 1,000 millimeters = 1 meter
– 100 centimeters = 1 meter
– 2.54 centimeters = 1 inch
– 12 inches = 1 foot
Density
Mass over Volume (g/mL)
Unit Conversion Scale
1000
100
10
1
0.1
0.01
0.001
Unit Conversion Rules
– Know what units you have
– Know where you’re going
– Never start with a ratio
– Don’t drop your units
– Units must always cancel
– Keep going until correct units are reached
– Don’t enter in calculator, until you are done writing it
– Enter all values into calculator before hitting the equal button
Significant Figures
– Measurements
– To know how accurate measurements taken in lab are
– Does not apply to counting numbers
– Atomic Masses don’t use; they use defined table values
– Table Values = Given/defined values and number of Sig. Figs.
Matter
– Anything that has mass and takes up space
Pure Substance
– Elements and compounds (1+ elements) only one type of matter is present.
Mixtures
– Contains one or more types of matter
Homogeneous Mixtures
– Types of matter cannot be distinguished with the naked eye (tap water)
Heterogeneous Mixtures
– Able to distinguish the components of the mixture and manually separate them (salad)
Atomic Theories of Matter (3):
1. Law of Conservation of Matter
2. Law of Definite Proportions
3. Law of Conservation of Mass
1. Matter’s neither created nor destroyed in chemical reactions
2. For a given pure compound, the proportion of elements by mass is fixed
3. Mass cannot be created nor destroyed in a chemical reaction; only changes form
Dalton’s Atomic Theory
1. Matter exists as elements, and nothing smaller.
2. Atoms of a given element, have identical chemical properties and identical masses.
3. Atoms of different elements have different chemical properties and different masses.
4. In a chemical reaction, atoms are indestructible and retain their identities.
5. Compounds are formed through combination of elements and small whole number ratios.
Protons
– Positively charged particle
Electrions
– Negatively charged particle
Neutrons
– Neutrally charged particle
Mass Number
– The sum of protons and neutrons in a nucleus.
Isotopes
– Same number of protons, but different number and weight of neutrons and different number of electrons.
– Generally only occurs in larger elements
Period Tables Organization
– Groups (Up and Down)
– Periods (Across)
– Organized by Atomic Number and chemical reactivity
Periodic Table Catergories
– Metals
– Nonmetals
– Metalloids
Atomic Number
– Number of protons in an element
Chemical Reactivity
– Organized in columns (up and down)
Metals
– Located on left side of Periodic Table
– Conduct electricity
– Ductile
– Shiny
Nonmetals
– Located on right side of Periodic Table
– Do not conduct electricity or heat
– Dull; not shiny
– Mostly gases
Metalloids
– Contain properties of both metals and nonmetals
– Except Al (metal) and At (nonmetal)
– Semiconductors ; in computer chips
Gas State
– Nonmetals on right side of PT
Liquid State
– Only Mercury (Hg); only element that’s a true liquid
Solid State
– Everything on left side of the PT.
– Excludes gases and mercury
Alkali Metals (Group 1)
– React vigorously with water
– 1-to-1 reactions with group 17
– 2-to-1 reactions with oxygen
Alkali Earth Metals (Group 2)
– React 1-to-1 with oxygen
– React 1:2 with group 17
Transition Metals (Groups 3 – 12)
– All conductors of electricity
– All are shiny
– They behave differently and have special properties
Halogens (Group 17)
– All gases
– React 1:1 with group 1
Noble Gases (Group 18)
– Chemically inert; don’t like to react with other elements
– They are chemically stable
– Used to provide inert atmosphere
Lanthanides
– Elements 58-71
– Rare earth metals
– Used in commercial magnets
Actinides
– Elements 90-103
– Mostly radioactive
– Not stable