Chemistry Final

reduction

• + to -

• oxidizing agent

• “gain”

oxidation

• - to +

• reducing agent

• “loss”

Breaking bonds is: endo or exothermic?

endothermic

H_mixture

less than 0 —> exothermic

H_solution

• H_solute + H_solvation

• H_lattice + H_hydration

H_hydration

less than 0 —> exothermic

H_solute

greater than 0 —> endothermic

H_solvent

greater than 0 —> endothermic

osmosis

• lower concentration —> higher concentration

• deals specifically with movement of solvents —> NOT ions

• attempting to reach equilibrium

Highest freezing point means…

the smallest change (in m x i)

“concentration”

M- molarity

higher charge density means…

releasing more energy, smaller size, and larger H_hydration

more H_hydration means…

stronger ion-dipole forces

Solution has higher/lower entropy compared to pure solvent/solute?

HIGHER

g —> s

• s < 0

• exothermic

s —> g

• s > 0

• endothermic

Main factors that affect rxn rate

• concentration: molecules must collide to react

• temperature: molecules must collide with enough energy

  • higher T = more energy = more collisions

• physical state: molecules must mix to collide

  • greater surface area = more contact to react

• catalyst: substance that accelerates chemical rxns —> not consumed itself

rate formula

change in concentration/change in time

Reaction rates

• average

• instantaneous

• initial

A catalyst is seen in the ____ side first, and the ____ side second

A catalyst is seen in the reactant side first (consumed first), and then in the product side second (produced second)

average kinetic energy depends on…

ONLY on the temperature —> the the same temperature, two molecules will have the same kinetic energy

average speed depends on…

the SIZE —> a bigger molecule will have a SLOWER average speed

what does a catalyst do to a rxn?

it lowers the activation energy; you know its a catalyst because it is above the arrow

order of HNO₂, order of NO; what if HNO₂ is tripled; what if NO is doubled; overall order?

• order HNO₂: 4

• order NO: -2

• HNO₂ tripled: 3⁴ = 81

• NO doubled: 2² = 1/4

• overall order: 2

Density equation

mass/volume

how is rxn order found?

found experimentally

collision theory

1. must collide

2. collide with enough energy

3. collide at right orientation

4. # collisions = product # particles

asking for how much of a product in a rate law question?

solve for amount of reactant, subtract from initial amount, and multiply by the balanced equation

overall rate is always positive/negative?

positive

the more likely for a collision to occur, the higher/lower the rate?

higher

what kind of substances dissolve in water?

ionic and polar substances —> like dissolves like

small alcohols will more easily dissolve in…

ionic compounds

large alcohols will more easily dissolve in…

hexane

1 cm³ =

1 mL

colligative properties depend on…

the number of particles present

“vapor pressure lowering”

delta P

for a BP question with water as the solvent, always add…

100 degrees C

for a FP question with water as the solvent, always subtract from…

0 degrees C

molality

mol solute / kg solvent

solute vs. solvent

• solute = what is dissolved

• solvent = what it is being dissolved in

are gases very soluble?

NO

solvation

surrounding a solute particle with solvent particles

solvation in water

hydration

charge density

ratio of ion’s charge to its volume

entropy is also known as

disorder

the solubility of gases in water increases/decreases as temperature increases?

decreases —> solubility of gases in water and temperature are inversely related

units S_g is usually in

gas solubility is usually in mol/L

molarity equation

amount of solute / volume of solution

examples of colligative properties

• VP

• BP

• FP

• osmotic pressure

simple cubic

• 1 atom/unit cell

• a = 2r

• r = a/2

• coordination number = 6

• worst packing efficiency

body cubic

• 2atoms/unit cell

• √3a = 4r

• r = a√3/4

• coordination number = 8

• middle packing efficiency

face centered

• 4 atoms/unit cell

• √2a = 4r

• r = a√2/4

• coordination number = 12

• highest packing efficiency

Angstrom to cm

1 A = 1 × 10^-8 cm

volatile liquids

• easily vaporized

• high VP

• weak IMK

polar shapes

• bent

• trig pyramidal

• T-shaped

• see-saw

• square pyramidal

As IMF increase…

• VP decreases

• BP increases

• size increases

polarizability

• increases as size increases

• Less cats, more ants!!

  • cation < neutral

  • anion > neutral

convex

strong cohesion but weak adhesion

concave

strong adhesion but weak cohesion

bond length

• more bonds = shorter

• bigger bond order = longer

finding enthalpy: given bond order

reactants - products

bond order

• larger bond order = stronger bond

a colling curve in endo/exothermic?

endothermic

a heating curve in endo/exothermic?

exothermic

“normal BP”

use 1 atm

the more dispersion forces, and larger/smaller?

larger

viscosity increases/decreases as IMF increases

increases

what do A and Z represent

• A = mass number —> protons plus neutrons

• Z = atomic number —> protons

group 1

alkali metals

group 2

alkaline earth metals

group 7

halogens

group 8

noble gases

covalent bonding

• between two non-metals

• share electrons

ionic bonding

• between a metal and a non-metal

• transfer of electrons

charge of Hg₂

2+

Alkanes are ____ compounds

• organic

• My Enormous Penguin Bounces Pretty High, Helping Our Neighbor David

• C_xH_2x+2

heterogeneous mixture

• visible boundary, not uniform

• oil and vinegar

homogeneous mixture

• no visible boundaries

• solution

• table salt dissolved in water

ways to separate a mixture

• filtration

• distillation

• crystallization

• chromatography

pure substances include…

elements and compounds

mass fraction

mass X / mass entire compound

theoretical yield definition

max product yield that can be expected based on the masses of the reactants —> can never be 100%

overall yield

multiply the yields of each step together (as decimals)

water’s solvent power

• uneven charge distribution

• bent molecular shape

• molecular polarity —> dissolves polar and ionic substances

strong vs. weak vs. non electrolytes

• strong electrolytes: completely dissolve —> ionic compounds

• weak electrolytes only partially dissolve

• nonelectrolytes: do not dissolve —> covalent compounds

strong acids

• hydro___ic acid

• nitric acid

• perchloric acid

• sulfuric acid

Strong bases

b on the periodic table

acid + base —>

salt + water

T/F: acids and bases must be ionic if they can dissociate?

FALSE

Bronsted-Lowry acid and base

• acid donates an H⁺

• base accepts an H⁺

How to find value of x for a hydrate?

1. find mols of hydrate

2. find mols of salt

3. divide mols hydrate by mols of salt

molecular vs. empirical formula

empirical is the formula you solve for initially, molecular formula is multiplied by an integer

effusion

• x effuses said times amount as y

• rate x / rate y = √y / √x

how to rank density of compounds

least dense = smallest molar mass

“neutralizes” means find…

which equation given an even number mols of H⁺ and OH^-

“collected over water”

find mols of thing you are looking for → subtract pressure of water from total pressure —> solve for volume

relationship between P and V

P and V are inversely related

relationship between T and V

proportional

P_final

P_initial x V_initial / V_final

partial pressure x

mole x / mole x + mole y