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Chem Final Study Guide!!!hey **Puns are Appreciated** We’re always making bad chemistry jokes

Frozone dies in incredibles 2  Unit 1: Measurement, Matter and Change You are living. You take up space. You have mass. You MATTER SI Units: Prefix

Symbol

Meaning

Giga

G

1,000,000,000

Mega

M

1,000,000

Kilo

K

1,000

Hecto

H

100

Deci

d

10

Centi

c

100

Milli

m

1,000

Micro

□

1,000,000

nano

n

1,000,000,000

Units- one divided by...

Dimensional Analysis-- converting units ○ unit you are trying to get rid of goes on the bottom ● Validity- how good the tools are ○ how well they measure ● Accuracy-- how close the measurement is to the actual value ● Precision-- how close the group of measurements are to one another Types of Measurements ● Quantitative-- data that can be measured ● Qualitative-- data that is observed SIGFIGS! ● RULES: ■ ■

Any number that’s not 0 is significant If the 0 is between two other numbers, it’s significant

■

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Atlantic/ pacific ● absent-- atlantic-- start from the right ● present-pacific--start from the left the answer can only have the same number of sigfigs as the number with the lowest number of sigfigs ADDITION/SUBTRACTION-- decimal places MULT/DIVIDE-- sigfigs the answer has as many decimal places as the number with the least decimal places

PERCENT ERRORs

Physical Properties- quality/condition that can be measured or observed without changing the substance’s condition ex. pH, boiling point, state of matter Kinetic Molecular Theory of Matter 1. All matter is composed of tiny particles 2. These particles are in constant motion 3. The amount of motion relates to temperature (higher temp= more motion) 4. solids/liquids/gases differ in motion and interaction of particles Solid

Liquid

Gas

close particles

close, not in orderly pattern

particles far apart

definite shape

particles free to flow-high temp

high temp-- spread out

definite volume

indefinite shape

indefinite shape and volume

can’t be compressed

definite volume, not easily compressed

easily compressed

Physical Changes- properties change, composition does not ● reversible or irreversible ● ex. rip a piece of paper Chemical Changes- composition is changing-- formation of new chemical substances ● burn, rot, rust, explode ● transfer of energy, change in color, produce gas, form precipitate (solid in water) Heating Curve

Law of Conservation of Mass and Energy ● mass and energy are neither created nor destroyed during a chemical reaction in a closed system (energy=heat) ● in all chemical or physical changes -- heat is absorbed or released ○ exothermic- release heat (freezing, combustion) ○ endothermic- absorb heat (melt, bake) Matter Classification 1. Pure Substance- uniform and definite composition a. elements- simplest form of matter, unique set of properties b. compounds- two or more elements chemically combined in a fixed proportion 2. Mixtures- physical blend of two or more substances a. heterogenous-- not evenly mixed, can tell there’s different things i. soup, oil and water, choc. chip cookies b. homogenous-- evenly mixed AKA SOLUTIONS i. salt and water, smoothie Separating Mixtures ● use differences in physical properties ○ magnetic, density, boiling  Unit 2: Atomic Structure and Nuclear Chemistry

Don't trust atoms… They make up EVERYTHING

Subatomic Particles ● protons-- inside nucleus, positively charged ● neutrons-- in the nucleus, no charge ● electrons-- outside nucleus, negative charge ● always have the same number of protons and electrons ● atomic number= how many protons ● isotopes= same element, differ in # of neutrons ● mass number= protons + neutrons ● ions- atoms that have lost or gained electrons Isotope Notation

OR X-mass# Average Atomic Mass (mass1 x relative abundance 1) + (mass2 x RA2) + … Radioactivity ● the stability of a nucleus depends on the ratio of neutrons to protons ○ N/P= 1.5 -- any higher or lower= radioactive ○ unstable nucleus emits radiation through radioactive decay ● Types of Radiation: ○

Alpha particle -- helium isotope

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Beta particle -- electron gamma radiation-- pure energy

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Deflection in a magnetic field:

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Penetration Power:

NUCLEAR REACTIONS ● Reactants➡Product ● reactions where radiation is produced are emission, decay or absorption reactions ● Natural Transmutation

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an atom of one element changes into an atom of a different element(ONE REACTANT) Artificial Transmutation ○ nucleus of an atom is bombarded by another particle (TWO REACTANTS) Balancing Nuclear Reactions: ○ make sure numbers on top add up to the numbers on top (and bottom/bottom)

HALF LIFE

NUCLEAR FISSION/FUSION ● Fission: splitting of a nucleus into smaller fragments ○ most use Uranium 235 as their fuel ○ Critical mass: min. amount of fissionable material there needs to be in order to keep the reaction going

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chain reaction FUSION: small nuclei combining to form a nucleus of greater mass ○ only occur at extremely high temp. (the sun)

ENERGY RELEASED DURING A REACTION: ● mass defect-- matter is “lost” by being converted into energy

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E- energy(joules), m- mass(kg), c- speed of light (3x10^8 m/s)

 Unit 3: Electrons and Periodic Table

I think I lost an electron… in fact, i’m positive! Bohr's Model: ● Energy is quantized ○ The electrons can only have specific amounts of energy Light as a wave: ● Wavelength and frequency are inversely proportional to each other C=λV V=frequency λ=wavelength light Wavelength:freezing point ●

Distance from one crest to another (usually measured in nanometers)

Frequency: ● How often the wave repeats in one second (1/s or Hertz) Photons: ● A packet of energy released when an electron emits energy ○ Energy of a photon : hv= hc λ ○ h= Planck’s constant: 6.63 x 10−34 J•S Quantum Numbers: ● Electrons are found in different positions around the nucleus, based on how much energy they have ● Each electron has four quantum numbers, which perfectly describe its position Quantum Numbers 1: Principal Energy Level ● Designated by the letter n ● n= 1, 2, 3, 4… ● Max numbers of electrons Sub-Levels (l) ● can be any integer between 0 and +/- (n-1) ● each possible value is assigned s, p, d, or f Orbitals ● within each sub-level-● any integer between +l and -l ● each kind has a different shape Spin

●

each orbital holds two electrons-- must have opposite spin ○ either +½ or -½

Electron Configurations: 1. Pauli Exclusion Principle ○ two electrons can only be in the same orbitals if they have opposite spin 2. Aufbau Principle ○ electrons fill the orbitals with the lowest energy first 3. Hund’s Rule ○ electrons will try to have their own orbitals before they have to share

Abbreviated Electron Configuration: [nearest noble gas] configuration from there THE PERIODIC TABLE ● Group 1= Alkali Metals ● Group 2= Alkaline Earth Metals ● Group 17= Halogens ● Transition Metals= groups 3-12

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Inner Transition Metals= f block

PERIODIC TRENDS: ● Nuclear charge- how strongly the electrons are attracted to the nucleus ○ more protons=more attraction ● Shielding- how electrons on the outside ring have less attraction because the inner rings are repelling it(more levels-- more shielding ● Atomic Radius- when two atoms of the same element are joined, measure atomic radius ○ distance between nuclei /2 ○ decreases across rows, increase across columns ● ionic radius- atoms that have gained or lose electrons ○ cations are always smaller ○ anions are always bigger ● ionization energy- amount of energy needed to “make” a positive ion ○ increase across rows, decrease across columns ○ farther from nucleus, easier to take away electrons ● electronegativity- ability of an atom to attract electrons when it’s in a compound ○ increase across rows, decrease across columns ● electron affinity- energy change that occurs when an atom gains an electron ○ don’t want electrons=low, want electron=high ○ increases across rows-- more valence electrons, want “just one more” ○ stays the same across columns-- same # of valence

Octet Rule- electrons want a full valence shell ● metals want to lose electrons ● nonmetals want to gain electrons

Lewis Structures:

ion lewis structure: IONIC BONDS- one metal, one non-metal ● requires the transfer of electrons, makes one positive and the other negative ○ attracted by electrostatic forces ● structure of ionic compounds: ○ Arranged in repeating 3D patterns ○ each ion is attracted to its neighbors-- CRYSTALLINE SOLIDS ■ high melting point ● electrical conductivity: ○ ions can conduct electricity if their ions are free to move around ● Crisscross method:

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○ switch charges of ions to get ratio cations- +, lost electrons anions -, gained electrons NAMING BINARY IONIC COMPOUNDS ○ first element keeps its name, second element -ide ○ ex, sodium chloride Polyatomic Ions:

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Units 4 & 5: Bonding and Chemical Formula Writing and Nomenclature Organic chemistry is difficult. Those who study it have alkynes of trouble.

COVALENT BONDING-- two or more nonmetals share electrons b/c neither will give them up ● physical properties ○ state at room temp-- not always solid (ionic is always solid) ○ melting/boiling point is lower than ionic

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Lewis Dot Structures: ○ find total # of valence electrons ○ least electronegative atom in the middle ○ dash between central atom and each outside atom (single bond) ○ fill in remaining valence electrons ■ use formal charge to check work ● (# of valence electrons)-(#of bonds)-(# of unshared electrons)=0 Bond Dissociation Energy ○ energy needed to break a bond ○ single=weakest, triple=strongest Resonance: when it has a double or triple bond that could be in multiple places and still mean the same thing

Exceptions to the octet rule: ○ when the total # of valence electrons is odd, the octet can’t be satisfied can have fewer or more than a complete octet ○ can only have expanded octet if it is in P3 or higher-- needs to fit the formal charge Molecular Orbital Theory: ○ 1. Sigma Bonds-- first bond of double/triple bonds and single bonds ○ 2. Pi Bonds-- second bond of double/triple bonds VSEPR Theory-- molecular geometry

Orbital Hybridization: ○ # of bonded atoms + # of lone pairs= # of hybrid orbitals ■ two: sp (linear, 180 deg) ■ three sp^2 (trigonal planar, 120 deg) ■ four: sp^3 (tetrahedral, 109.5 deg) ■ five: sp^3d (trigonal bipyramidal) ■ six: sp^3d^2 (octahedral)

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DIATOMIC ELEMENTS: ○ Br I N Cl H O F Polar Covalent Bonds vs Molecules ○ bond-- only talking about the bond ○ molecule, bonds can be polar, but pulling in opposite directions, making it a non-polar molecule Polar compounds only dissolve in other polar compounds non-polar only dissolve in non-polar

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“Like dissolves like”

NAME MOLECULAR COMPOUNDS: 1. name elements in compound 2. first keeps name, second ends in -ide 3. use greek prefixes always on second, don't use on first if there is only one (don’t need mono-)

Organic Compounds-- compounds that primarily contain carbon ● carbon has 4 valence electrons, so it can form a maximum of 4 bonds ● carbon is a relatively small atom, so other atoms can bond closely to it Examples of Organic Compounds: 1. natural gas, petroleum, coal 2. carbohydrates, proteins, lipids (fats) 3. DNA/RNA 4. aromatics (like perfumes/colognes) 5. every biological molecule that exists

Hydrocarbons: ● The simplest organic compounds, which only contain hydrogen and carbon ○ ex. motor oil, asphalt Alkanes: ● Hydrocarbons that only have single bonds ○ a) straight chained ○ b) branched ● CNH2N+2 Because these compounds have the maximum amount of hydrogen atoms attached to them as possible, they are called saturated To name a straight-chain alkane: 1. Count the number of carbons in the compound 2. Write down the appropriate by the ending -ane 1-Meth 4-But 7-Hept 10-Dec 2-Eth 5-Pent 8-Oct 3-Prop 6-Hex 9-Non How to name branched chain alkanes: 1. Find the longest continuous carbon chain in the molecule ( parent chain) 2. Start numbering the carbons in the parent chain, such that the branches have the lowest possible numbers 3. Write down the number where the branch occurs. then count the number of carbons and that branch. Use the appropriate prefix, followed by the ending -yl

4. If a group shows up more than once, write down both numbers, separated by a comma. Use appropriate prefix 5. Name the branches in alphabetical order, ignoring any prefixes 6. Commas separate numbers, hyphens separate numbers and words. The entire name is written without spaces. Intermolecular forces of attraction 1. London dispersion forces: a force of attraction that exists between molecules, because of the motion of electrons 2. Polar molecules are attracted to each other, because of the formation of permanent dipoles a. stronger than London dispersion forces 3. Hydrogen bonding: the strongest of the three types, which occurs when N, O, or F is directly bonded to a H atom Boiling point of Alkanes Boiling Involves separating each of the molecules that are attracted to each other 1. bigger molecules have more electrons, so the attraction will be stronger 2. bigger molecules also pack well together, so their boiling point will be higher 3. straight chain alkanes pack much more than branched alkanes, so their boiling point will be higher Unsaturated hydrocarbons Hydrocarbons that have less than the maximum amount of hydrogens possible Naming: 1. Find the longest, continuous carbon that contains a double or triple bond 2. Number the chain, so that the double or triple bond has the lowest possible number 3. Count the number of carbons to find the appropriate prefix 4. Alkenes have double bonds and their names end in -ene. alkynes have triple bonds and their names end in -yne Isomers: ● Structural isomers: compounds that have the same chemical formulas, but different molecular structures ● Geometric isomers: groups are arranged differently around a double bond ● Stereoisomers: isomers that has the same molecular structure, but are arranged differently in 3D space

Hydrocarbon rings: 1. Cyclic Hydrocarbon: A hydrocarbon found in the form of a ring

2. Aromatic Hydrocarbons: an organic compound that contains a benzene ring (or other ring with similar bonding) a. groups attached to benzene: named as derivatives of benzene b. benzene attached to a parent chain: called aphenyl group

Functional Group: ● A small group of atoms, which are responsible for how a particular organic compound reacts with other compounds Halocarbons: ● A carbon containing compound, which includes a halogen (group 17 element) substituted for a hydrogen atom ○ Naming: ■ Name the parent chain ■ Add the stem of the name for the halogen to the beginning of the name Boiling point of Halogens: ● The boiling point will increase as more halogen atoms are substituted for H atoms.

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Unit 6: Chemical Reactions and Predictions

A neutron walks into a bar. He asks the bartender, "How much for a beer?" The bartender offers him a warm smile and says, "For you, no charge". Chemical reactions: ● Reactants: one (or more) substances present before the reactions ● Products: one (or more) new substances present after the reaction ● As reactants are converted, the bonds holding them together are broken and new bonds are formed Symbols used in chemical reactions (s)- solid, (l)- liquid, (g)- gas, (aq)- aqueous solution (has been dissolved in water) +- used to separate two reactants or two products ➡- used to separate the reactants and the products Balancing chemical equations: Coefficients: Numbers that are placed in front of chemical formulas Coefficients multiply with the subscripts in the chemical formula to give you how many atoms of each element you have Steps to balance: 1. Count up how many atoms of each element you have on the left and on the right. If there are any polyatomic ions that are on both sides, count that as one group

2. Use coefficients to make sure that there is the same amount of each element/polyatomic ion on each side. Work on one element at a time Types of Chemical reactions: ● Combination ○ two or more substances react to form a single new substance ● Decomposition ○ a single compound breaks down into two or more simpler products ● Single Replacement ○ a single element replaces a second element in a compound ■ - replace ■ + replace + ● Double Replacement ○ two ionic compounds exchange their positive ions ● Combustion ○ an element or compound reacts with oxygen

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Unit 7: The Mole & Chemical Equation Stoichiometry What do you get when you cut an avocado into 6.02x10^23 pieces? GuacaMOLE! How is matter measured? 1. Counting a. Count up how many things you have 2. By mass (grams) a. Weigh how much of the thing you have 3. By volume (liters) a. Measure the volume of the thing you have Conversion Factors ● Fractions where the numerator and the denominator are the same amount of something, expressed in different units ○ Multiply by a conversion factor to move from one unit to another ○ Unit you want goes on top ○ Unit you want to get rid of goes on bottom Measuring matter ● 1 Mole= 6.02 x 1023 representative particles ○ ○

Works for any substance Abbreviated “mol”

Converting from particles to moles: 12.04 x 1023 rp ( 1 mole

) = 2 moles

23

( 6.02 x 10 rp ) Converting from moles to particles 9 moles (6.02 x 1023 rp ) = 4.418 x 1024 rp (

1 Mole

)

Volume ● Applies only to gases at STP (standard temperature and pressure) ○ -0°C and 1 ATM ● -22.4L of any gas= 1 mole Molar Mass: # of grams of a substance in one mole ● NOT the same for every substance ○ Depends on the # of atoms of each element ● Same as mass on periodic table 1. 2. 3. 4.

Write down # of each element (chemical formula) Look up average atomic mass of each element Multiply number of atoms by average atomic mass Add everything

Percent Composition ● Percentages that tell us how much of a whole is made of a single part (adds up to 100%) Percent Composition from Mass Data ● (M ass of an element ÷ M ass of a compound) × 100 Composition from The chemical Formula ● (M ass of element in 1 mole of a compound ÷ molar mass of a compound) × 100 Empirical Formulas ● A formula that shows the lowest whole number ratio of the atoms in the compound ○ The subscripts in the formula cannot be divided by the same number Steps for Using the Percent Composition to Determine the Empirical Formula 1. Write the percentages out as grams 2. Convert the number of grams of the elements you have to moles 3. Write the number of moles of each element as the subscripts in your chemical formula 4. Divide your subscripts by the smallest number 5. If the subscripts are still not whole numbers, multiply by the lowest number you can to make them whole numbers Molecular Formulas

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Definition: a formula that tells exactly how many of each kind of atom is present in the compound ○ Ethanoic Acid- C2H4O2 ...