56 terms

Chemistry Exam

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Homogeneous
A mixture with the same particles
Heterogeneous
A mixture with different particles
Atom
The smallest particle of an element
Molecule
Atoms linked together. The smallest particle of a compound.
Element
A pure substance made of the same atoms.
Compound
A pure substance made of the same molecules.
Mixture
An impure substance made of a combination of atoms, molecules, or both.
Pure Substance
Made of the same element or compound.
As the temperature of matter increases...
The mollecular motion increases and the molecular interractions decreases.
Solids
Move little
Don't need a container
Definite shape
Definite volume
Liquids
Move easily
Needs a container
Indefinite shape
Definite volume
Gases
Move rapidly
Can fill a container
Indefinite shape
Definite volume
You can compress a gas
Plasmas
Extreme amount of energy
Electrons knocked off by collisions
Most abundant state of matter!!!
Kinetic Theory of Matter
1. All matter is composed of small particles.
2. The particles are in constant motion.
3. The particles are colliding with each other and their container.
States of Matter Cycle
Solid to Liquid- melting
Liquid to Solid- freezing
Liquid to Gas- evaporation
Gas to Liquid- condensation
Solid to Gas- sublimation (like dry ice)
Atomic Mass Units (AMU)
Roughly how much a part of an atom weighs:
Protons= 1 AMU
Neutrons= 1 AMU
Electrons= 0 AMUs
How do you calculate the number of neutrons?
1. Round the Atomic Mass to the nearest whole number. (This gives you the Mass Number)
2. Mass Number- Atomic Number= Number of Neutrons
Isotopes
An element with the same protons and electrons, but with extra neutrons.
Isotopic Notation
Cl OR Chlorine- 35
17 35

17 is the atomic # and 35 is the mass #
The CLOSER an electron is to the nucleus, the _______ amount of energy it has.
Less
# of electrons per shells
Shell 1= 2 electrons
Shell 2= 8 electrons
Shell 3= 18 electrons
Shell 4= 32 electrons
Periods
Rows <----> Tell the number of electron shells the element has
Groups
Columns (Up and down) Tell how many electrons go in the outer shell (Valence Electrons)
Bohr Diagrams
Draws little rings around the nucleus with dots on them
Properties of Metals
Good conductors of heat and electricity
Malleable
React with water
Properties of Nonmetals
Poor conductors
Not malleable
Break easly
Properties of Metalloids/Semi-conductors
Conduct heat better than nonmetals, but worse than metals
Transition Metals
Have a variable number of VEs
Ion
An atom that has gained or lost electrons
Ionic Bonds
Metal+Nonmetal
LOSE/GAIN VEs

To write: Flip flop the oxidation numbers.
Ex: Fe(III) O = Fe2O3

ALWAYS END IN -IDE
Covalent Bonds
Nonmetal+Nonmetal (Coworkers)
SHARE VEs

To write: DO NOT flip flop!
Ex: Tribromine Tetraoxide = Br3O4

If the first element has only 1, don't use a prefix.
Always use prefixes for the second element, however.
ALWAYS END IN -IDE, TOO!
Organic Compounds
Covalently bonded
Always have Carbon and Hydrogen
Hydrocarbons
Compounds made of only Carbon and Hydrogen
C- Single bonds, called Alkanes
C= Double bonds, called Alkenes
C (3 lines) Triple bonds, called Alkynes

1 Meth 5 Pent
2 Eth 6 Hex
3 Prop 7 Hept
4 But 8 Oct

Used for fuels
Polymers
Large organic molecules made up of bonded monomers

PROTEINS are linked together by AMINO ACIDS in ENZYMES in tissue building. (Meat, beans)
NUCLEIC ACIDS (controls reproduction of cells) are linked together by NUCLEOTIDES in DNA and RNA
CARBOHYDRATES are linked by MONOSACHARIDES in STARCHES (rice, potatoes, pasta)
LIPIDS (fats and oils)
What is the difference between a CHEMICAL change and a PHYSICAL change?
You can change the products of a physical reaction back into the reactants, but if there's a chemical change, you can't undo it!
Law of Conservation of Mass
1. Matter cannot be created or destroyed (Therefore chemical equations should be equal)
2. The number of atoms in the reactants should equal the number of atoms in the products.
Synthesis Reaction
A+B=AB
Decomposition Reaction
AB--> A+B
Single Replacement Reaction
AB+C--> CB+A
Double Replacement Reaction
AB+CD--> CB+AD
Combustion Reaction
O2 + hydrocarbon --> CO2 + H2O + energy.
Water and Carbon are always the products
What can we do to make something dissolve faster?
Increase the surface area (crush up the alka seltzer)
Stir it
Increase the temperature
Increase the concentration
Dilute
Small amount of solute is dissolved in the solvent
Concentrated
Large amount of solute dissolved in solution
Unsaturated Solutions
Are able to hold more solute
Saturated Solutions
Can't hold any more solute
Supersaturated Solutions
Are holding more dissolved solute than it's able to. To do this, you have to heat up the solution
Properties of Acids
All contain hydrogen
Produce Hydrogen (H) ions and Hydronium (H3O) ions
Are electrolytes
Are corrosive
TASTE SOUR
Properties of Bases
Produce Hydroxide (OH) ions
Are electrolytes
TASTE BITTER
Two different types of Bases
Antacids (anti-acids) and Cleaners
How can we tell if a substance is an Acid or a Base?
Look at the formula. If there are Hydrogen or Hydronium ions, then it's an acid. If there are Hydroxide ions, then it's a base.
Strength of Acids and Bases
Depends on how completely a compound is pulled apart when dissolved in water. If the acid/base is STRONG, then the compound will totally seperate. If it's WEAK, then some will seperate and soem will not.
pH
The measure of concentration of H+ ions in a solution.
The more H+ ions, the lower the pH
The fewer H+ ions, the higher the pH

As you approach neutral, the acids/bases weaken!!!
Neutralization
Bases can neutralize the effects of acids, and vice versa.
If you eat a bunch of Italian food (acidic), take a Tums (base) to neutralize the effects.
Acid + Base --->
H2O and a salt
Polyatomic Bonding
END IN -ATE or -ITE
Ex: Barium Nitrate = Ba(N)3)2

You DO flip-flop!
Keep the -ates and -ites from the polyatomic atoms if it's last, but if it's first, then put -ide at the end of the elements.