Important Things to remember for Ap Chem

Strong Acids

H2SO4, HI, HBr, HNO3, HCl, HClO4

Strong Bases

LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

What do acids do?

Donate proton

What do bases do?

Recieve a proton

smaller Ka=

weaker acid

what side does equillibrium favor for strong acids and bases?

The opposite side of the strong acids and bases

small k=

equilibrium shifts to the reactants

large k=

equillibrium shifts towards the products

reactions are driven by

decreasing enthalpy and increasing entropy

what happens to entropy when volume is decreased

entropy is decreased

what do you use as concentration for pH

mol excess/ L solution

when thermodynamically favorable, what is g?

g<0

when volume is reduced, where does equilibrium shift?

the direction with the least mols of gas

what elements can have expanded octets?

Xe, I, Se, S, P

what is the equation to calculate the pH of a buffer?

pH=pKa+log H3O/OH

if reactants increase, what happens to Q and what is favored?

Q decreases and products are favored

if products increase, what happens to Q and what is favored?

Q increases and reactants are favored

formal charge

valence electrons in periodic table- valence electrons in structure

calculate percent yield

actual yield/calculated yield *100

percent error

|correct-calculated|/correct *100

enthalpy of bonds

H=bonds broken- bonds formed

% dissociation of a weak acid

H3O/HA *100

at the equivalence, what is the relationship between acid and base?

MV of acid=MV of base

E of a cell is calculated by

E cathode- E anode

characteristics of ionic bonds

metal and nonmetal, brittle, high melting point, conduct electricity when dissolved in solution

characteristics of covalent bonds

nonmetals, lower melting point, don’t conduct electricity well when dissolved

how to calculate hybridization

atoms the central atom touches + unshared pairs

London Dispersion Forces

more electrons, causing more polarizable, causing stronger LDF

Dipole dipole

polar molecules only

Hydrogen bonding

Only with O-H, N-H and F-H

covalent network solids

highest melting point, very hard and brittle

molecular solids

low melting point, weak intermolecular forces

ideal gases are

high temp, low pressure, or are small molecules

UV or visible light

transition to different energy level

infared

vibrational

microwave

rotational

Oxidation

lose electrons

Reduction

gain electron

what happens if the reaction intermediate is part of the rate determining step?

the rate law for the formation of the intermediate needs to be plugged in

endothermic

gains heat, surrounding colder, H is positive

exothermic

lose heat, surroundings warmer, H is negative

make sure to omit these things from equilibrium

solids and liquids

the only way equilibrium constants can be changes is with

temperature

if k is greater than one

equilibrium lies to the right, and there are lots of products that are going to be used up

what happens when K is less than one

equilibrium lies to the left, lots of reactants that are going to be used up

what happens to k when the reaction is flipped

k becomes the reciprocal

what happens to k when the reaction is doubled

k gets squared

what happens to k when reactions are added

k is multiplied by the two k of the reactions

adding a substance results in

a shift to the other side

removing substance results in

a shift to the same side

adding heat results in

a shift to opposite side

decreasing heat results in

a shift to same side

if Q<K

reaction goes to the right

if Q>K

reaction goes to left

before pKa (half equivalence point), what dominates?

the weak acid, it is greater than the conjugate base

after pKa (half equivalence point)but before equivalence point, what dominates?

the conjugate base, it is greater than the weak acid

after the equivalence point, what dominates?

the strong base begins to dominate

stronger acids tend to have

more oxygen

weak bases tend to have

N and H

for an acid base indicator

the indicator should have pKa close to the pH of equivalence point

a reaction is thermodynamically favorable if H is

negative (exothermic)

a reaction is thermodynamically favorable if S is

positive

if H and S are positive

favorable at high temps

if H and S are negative

favorable at low temperatures

electrodes flow from

the anode to cathode

does the anode or cathode gain mass

the cathode

reduction is in the

cathode

oxidation is in the

anode

in the salt bridge, positive ions (cations) go to

the cathode

in the salt bridge, negative (anions) ions go to

the anode

how to calculate E

cathode-anode

standard conditions

25 C, 1 atm, 1 M

for non standard conditions, use

E-RT/nF *lnQ