AP Chemistry SUPER study

Stuff to MEMORIZE

Avogadro’s Number

6.022 × 10²³ particles in 1 mole

Average Atomic Mass

Weighted average of the mass of isotopes based on abundance

Mass Spectra

shows relative abundance of isotopes

Molecular Formula

A chemical formula that shows the number and types of atoms in a molecule, without indicating the arrangement of atoms.

Empirical Formula

Molecular Formula reduced to lowest terms

Elemental Analysis

determines purity of a substance

Coulomb’s Law

q₁ * q₂ / d² - magnitude of the attractive force

Electron Configuration Order

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁴ 6d¹⁰ 7p⁶

Orbital Notation

a way of representing electron configurations using arrows in boxes to indicate the spin and arrangement of electrons in orbitals.

Photoelectron Spectroscopy

Shows how much energy required to remove an electron. Height of peaks = how many electrons required. Label across left to right in same order as electron configuration.

First Ionization Energy

Energy required to remove the last electron in the gaseous form of an atom

Periodic Trends Show…

Atomic/Ionic Radius, Electronegativity, ionization energy,

Electronegativity

How well something can attract an electron (how badly does it want to be a noble gas)

Factors that Influence Atomic Radius

Magnitude of the attractive force, number of electrons (size of electron cloud)

Periodic Trends: Horizontal

Number of protons/magnitude of attractive force

Periodic Trends: Vertical

Number of electrons/size of electron cloud

Covalent Bond

two nonmetals share electrons

What decides Polarity

Uneven structure/more difference in electronegativity

When do atoms have the highest potential energy

When not bonded

When do atoms have the lowest potential energy

when bonded

Melting point of an ionic compound is influenced by…

Magnitude of charge (stronger charge = higher M.P.), size of atom (smaller atom = higher M.P.)

Substitutional Alloy

New metal takes the place of the old metal (roughly the same size)

Interstitial Alloy

New metal goes between atoms of the old metal (new metal is smaller)

Steps for Lewis Diagram

1. Figure out total number of valence electrons

2. Connect Molecules and subtract 2 ve for each bond created

3. complete octets

Octet Rule

An atom is most stable with 8 valence elctrons

Exceptions to the octet rule

H is stable with 2, B is stable with 6, Nonmetals with 3+ energy levels can have expanded octet ie noble gases.

Formal Charge

Valence Electrons — Showing Electrons (bonds count as 1). Molecules are most stable with each atom at a 0 formal charge.

Sigma Bond

Straight bond (1 in each single, double, triple bond)

Pi Bond

Looped Bond (1 in double bond, 2 in triple bond)

Bond Lengths (single, double, triple)

Longest to shortest: Single, double, triple

Hybridization

Orbitals that are partially one type and partially another type

Determining Hybridization…

1. add sigma bonds and unshared electron pairs

2. pair sum to hybridization type 2=sp

Hybridization sum = 2

sp

hybridization sum = 3

sp²

hybridization sum = 4

sp³

hybridization sum = 4

sp³d

4 sigma bonds (VSEPR)

Tetrahedral shape, 109.5 angle

3 sigma bonds + 1 unshared pair (VSEPR)

trigonal pyramidal shape, 107 angle (unshared pairs repel more than bonds do)

2 sigma bonds + 2 unshared pairs (VSEPR)

bent shape, 105 angle

3 sigma bonds (VSEPR)

trigonal planar, 120 angle

2 sigma bonds + 1 unshared pair (VSEPR)

angular, 117 angle

5 sigma bonds (VSEPR)

Trigonal Bipyramidal, 90 and 120 angles

4 sigma bonds + 2 unshared pairs (VSEPR)

square planar, 90 angle

6 sigma bonds

octahedral, 90 angle

What particles can experience London Dispersion Forces

All

What particles can experience Dipole-Dipole Forces

Polar molecules

What particles can experience Hydrogen Bonds

polar molecules with O-H, N-H, or F-H bonds

Order the Intermolecular forces by strength

London Dispersion - Dipole Dipole - Hydrogen Bond - Ion Dipole

Tiebreaker for determining strength of ionic forces

Charge differential, size

Tiebreaker for determining strength of london dispersion forces

more electrons = stronger LDF

shape of ionic solids

crystal lattice

Which type of solid conducts electricity the best (ionic, molecular, covalent network)

Ionic

Which type of solid is the strongest (ionic, molecular, covalent network)

Covalent network

properties of gases

P (pressure), V (volume), T (temperature), n (number of moles)

Pressure and Temperature are _______ proportional

directly

Volume and Temperature are _______ proportional

directly

Pressure and volume are _______ proportional

inversely

Combined Gas Law (formula)

P₁V₁T₂ = P₂V₂T₁

Ideal Gas Law (formula)

PV = nRT

Dalton’s Law of partial pressure (formula)

Partial Pressure of gas A = X_gas * P_total X=ratio of gas A to total

Temperature is the same as

Average Kinetic Energy

Graham’s Law of Diffusion

Larger (greater mass) gas molecules diffuse slower than smaller molecules

Ideal Gas

Zero mass, Weak attractive forces, High temperature, low pressure

A gas that is larger than an ideal gas has a (pos/neg) deviation from the ideal gas

Positive

A gas that is larger than an ideal gas has a (pos/neg) deviation from the ideal gas

Negative

Mole Fraction (formula)

Mole fraction = moles_substance/moles_total

How to create a solution

Dissolve a small amount of the solute in distilled water, then dilute the solution

Electrolytes

dissociate in water and conduct electricity in aqueous form

Distillation

Uses different boiling points to separate substances

Chromatography

Uses polarity and diffusion to create a chamber where one substance passes slower or faster in order to seperate them

Gases dissolve more in liquid at ______ temperatures

lower

Solids dissolve more in liquid at __________ temperatures

higher

Gases dissolve more in liquid at ______ pressure

higher

electromagnetic energy is (quantum/continuous)

quantum (in “packets” of photons)

UV visible light causes electrons to…

jump to different energy levels

Infrared radiation causes molecules to …

vibrate

Microwave radiation causes molecules to…

rotate

Wave Formulas (formula)

E = hv and c = lambda v

Spectroscopy

uses color intensity to determine the concentration

Beer Lambert Law (formula)

A = εbc Absorbance and concentration change

What Ions are always soluble

Nitrates (NO₃^—) and Alkali Metals (Li⁺, Rb⁺, Cs⁺, K⁺, Na⁺, NH₄⁺)

All chlorides, bromides, and iodides are soluble except…

Silver, lead, or mercury (Ag⁺, Pb²⁺, Hg₂²⁺)

All sulfates are soluble except…

Silver, lead, mercury, (Ag₂SO₄, PbSO₄, Hg₂SO₄) and group 2 alkali metals (CaSO₄, SrSO₄, BaSO₄)

Aside from the always soluble ions, what anions do not dissolve

chromates (CrO₄^— and Cr₂O₇^2—), phosphates (PO₄^3—), carbonates (CO₃^2—)

Spectator Ion

Ions that do not participate in the chemical reaction

Net ionic equation

shows the chemical equation for the ions that are actually reacting (excludes spectator ions)

Which three substances do not exist at normal conditions and produce a gas evolution reaction

H₂CO₃, H₂SO₃, NH₄OH

Metal Oxide + Water —>

Metal Hydroxide

Nonmetallic oxide + Water —>

Acid

Diphosphorus pentoxide + water —>

Phosphoric Acid

Metal Carbonate (heat) —>

Metal Oxide + Carbon dioxide

Metal Chorate (heat) —>

Metal chloride + Oxygen gas

Process for determining limiting reactant

convert both reactants’ amounts (in moles) to moles of the same product. Whichever produces less product is the limiting reactant

Percent Yield (formula)

% yield = Actual Yield / Theoretical Yield * 100

Oxidation - Reduction reaction (REDOX)

one atom oxidizes (loses electrons) and another reduces (gains electrons)

Oxidation

Losing electrons, becoming more positive

Reduction

Gaining Electrons, becoming more negative

Oxidation number for lone elements in their natural form

0

Oxidation number of monatomic ions

Same as charge

Oxidation number of alkali metals

+1