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studies matter and the physical and chemical changes it undergoes
◦ Organic – carbon compounds (DNA, etc)
◦ Inorganic – non carbon cpds (medicines,etc)
◦ Physical – matter/energy changes (atoms)
◦ Analytical – material makeup (geometry of atoms)
◦ Biochemistry – chemistry of living things
◦ Theoretical – use of physics to understand chemical phenomena (quantum chemistry)

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Matter- anything that has mass and volume
Atom- smallest unit of an element that keeps the properties of element
Element- pure substance made of only one type of atom
Compound- substance made of 2 or more types of atoms that are chemically bonded
Molecule- type of compound in which bonds are covalent bonds

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Element
◦ Composed of identical atoms
◦ Cannot be made simpler by chemical or physical means
◦ EX: copper wire, aluminum foil

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Compound
◦ Composed of 2 or more elements in a fixed ratio that are chemically combined
◦ Able to be separated by chemical means
◦ Properties differ from those of individual elements
◦ EX: table salt (NaCl)

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Variable combination of 2 or more pure substances.
◦ Not chemically combined and can be separated through physical means
Heterogeneous Homogeneous

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Homogeneous (solutions)
◦ Very small particles
◦ Particles don’t settle
◦ Appear to be the same throughout
◦ Examples: air, brass, salt water
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Heterogeneous
◦ Medium/large particles
◦ Particles may/may not settle
◦ Not the same throughout
◦ Examples: concrete, cookie dough

Compound
One kind of piece-
Molecules
Making is a chemical change
Only one kind
Mixture
More than one kind -
Molecule or atoms
Making is a physical change
Variable composition

yes
no
Can it be physically separated?
PURE SUBSTANCE MIXTURE yes Is the composition uniform ?
Homogeneous
Mixture
(solution) no
Heterogeneous
Mixture yes
Can it be chemically decomposed?
Compound Element no

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Characteristic properties of matter are used to classify substances
Types of Properties:
◦ Extensive Property
 depends on the amount of matter
 Ex: volume, mass
◦ Intensive Property
 does not depend on amount
 Ex: density, boiling/melting point, ability to conduct heat/electricity

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Examples:
◦ boiling point
◦ volume
◦ mass
◦ density
◦ conductivity intensive extensive extensive intensive intensive

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Physical Property
◦ can be observed without changing the identity of the substance.
◦ Mixtures separated using physical properties
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Chemical Property
◦ describes the ability of a substance to undergo changes in identity
◦ Chemical reactions are evidence

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Examples:
◦ melting point
◦ flammable
◦ density
◦ magnetic
◦ tarnishes in air physical chemical physical physical chemical

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Physical Change
◦ Changes the form of a substance without changing its identity
◦ Properties remain the same
◦ Phase changes, dissolving, cutting, bending, etc
◦ Mixtures separated with a variety of techniques (filtering, evaporation, boiling, etc)
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Chemical Change
◦ Changes the identity of a substance
◦ Products have different properties
◦ Combustion, production of odors, gases, light, rusting, precipitation, cooking,etc

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Reactants – The substances that react in a chemical change (stuff you start with)
Products – The substances that are formed by the chemical change (what you make).
NEW PROPERTIES
Not easily reversed reactants product carbon + oxygen → carbon dioxide

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Signs of a Chemical Change
◦ change in color or odor
◦ formation of a gas
◦ formation of a precipitate (solid)
◦ change in light or heat

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Examples:
◦ rusting iron
◦ dissolving in water
◦ burning a log
◦ melting ice
◦ grinding spices chemical physical chemical physical physical

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Exothermic Reaction- reaction that gives off energy (feels warm on outside)
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Endothermic Reaction- reaction that uses up energy (feels cold on outside)

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Energy is always involved when physical or chemical changes occur.
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Energy can be in various forms.
◦ heat
◦ light
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Law of Conservation of Energy.
◦ Energy can be absorbed or released in a change, it is not destroyed or created.

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Solids
◦ very low KE - particles vibrate but can’t move around
◦ fixed shape
◦ fixed volume

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Liquids
◦ low KE - particles can move around but are still close together
◦ variable shape
◦ fixed volume

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Gases
◦ high KE - particles can separate and move throughout container
◦ variable shape
◦ variable volume

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Plasma
◦ very high KE - particles collide with enough energy to break into charged particles (+/-)
◦ gas-like, variable shape & volume
◦ stars, fluorescent light bulbs, CRTs

◦ Particles of matter are always in motion.
◦ As temperature increases, so does speed (Kinetic
Energy) of particles
◦ KMT evidence exists in the presence of the four states of matter

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Changing from any state to another state involves the addition or removal of energy from the system
Melting, freezing, vaporizing, evaporation, boiling, sublimation, condensation

Melt
Evaporate
Solid Liquid Gas

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Groups (aka: families)
◦ vertical columns
◦ numbered 1  18
◦ have similar chemical properties
Periods
◦ horizontal rows
◦ properties changes consistently across a period

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Metals
◦ an element that is a good conductor of electricity
◦ at room temperature, most are solids
◦ malleable- can be rolled or hammered into sheets
◦ ductile- can be made into wire
◦ high tensile strength- can resist breakage when pulled
◦ most have silvery or grayish white luster

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Nonmetals
◦ an element that is a poor conductor of heat and electricity
◦ many are gases at room temperature
◦ some are solids: usually brittle, not malleable
Various nonmetal elements
(a) carbon, (b) sulfur, (c) phosphorus, and (d) iodine

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Metalloids
◦ an element that has some characteristics of metals and nonmetals
◦ appear along staricase line
◦ B, Si, Ge, As, Sb, Te
◦ all are solids at room temperature
◦ less malleable than metals but less brittle than nonmetals
◦ are semiconductors

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Noble Gases
◦ generally unreactive gases
◦ in far right column of periodic table