Chem Sec 3

Mole fraction

1 gas type / all gas types

total pressure

isolate p in pv=nrt

partial pressure

isolate p in pv=nrt but only use moles of element wanted

solubility of solids

increase with temperature (think sugar in hot water)

solubility of gas

decreases with temperature (think soda in hot sun)

most soluable with

• like IMFS

• like polarities

miscibility

always mixes to form a solution

molarity

moles solute / liters solution

solute

gets dissolves

solvent

dissolved into (v like a vase)

dilutions

M1V1 = M2V2 *L

electrolytes

• breaks into cations and anions in water

• can conduct electricity

• stabilized electron movement

• salts

• nonpolar

• can form precipitates (nonsoluable)

thermodynamics

• ΔG

• E

• Gibbs free energy

• favorability of a reaction

• spontaneity of a reaction

finding favorability of a reaction

E_product - E_reactants

kinetics

rate of reaction

negative favorability of a reaction

• favorable

• energy was released

• system became more stable

• high to low on graph

positive favorability of a reaction

• unfavorable

• energy was absorbed

• system became less stable

• low to high on graph

total energy in universe

0

ΔE

change in energy of a system

heat + work

+q

system gained energy

-q

system lossed energy

+w

work done on system

-w

work done by system

Enthalpy

• ΔH

• heat change in reaction

• useable energy

+ΔH

• endothermic

• heat entered system

• unfavorable

• became less stable

-ΔH

• exothermic

• heat left system

• favorable

• became more stable

standard enthalpy

• most stable form

• 1 atm

• 298.15 k

• standard state reactants

vaporization enthalpy

• endothermic

• heating up

• gaining energy

• unfavorable

• less stable

freezin enthalphy

• exothermic

• cooling down

• losing energy

• favorable

• more stable

short bonds

stronger, more energy to break

multiple bonds

more energy to break

ΔH_rxn bond energy

Σ broken - Σ formed

favorable reactions bond energy

breaks weak bonds to form stronger ones (think freezing)

Entropy

• ΔS

• degree of freedom

• distribution / arrangement of energy

• more is better (think 6 book combos vs 2)

spontaneous reactions

overall favorability

exothermic

enthalopically favorable

endothermic

enthalopically unfavorable

ΔS_rxn 

S_product - S_reactant

state high in entropy

gas, everything else 0

+ΔS

• increasing entropy

• favorable

• more distributed

-ΔS

• decreasing entropy

• unfavorable

• less distributed

ΔS_rxn = 0

when # mol gas doesn’t change

-ΔG

• exergonic

• spontaneous moving forward

ΔG = 0

• energies equal

• thermodynamic equilibrium

+ΔG

• endergonic

• not spontaneous moving forward

ΔG equation

ΔH - (T*ΔS)

H

horrible (- favorable)

S

super (+ favorable)

G

glum (- favorable)

exergonic

x = - = favorable

k

king; final answer

J

jockey; used in work

E_{a equation}

top of hill - starting point

smaller E_a

faster reaction

transition state

• peak of graph

• can’t separate

• unstable

Rate_forward aq

K_f [x]^a[y]^b

Rate_reverse aq

K_r [x]^a[y]^b

solids and liquids in rate law problems

ignored

rate laws of gasses

partial pressure

Rate_forward gas

K_f P^a_x * P^b_x

Rate_reverse gas

K_r P^a_x * P^b_x

chemical equilibrium

• K_eq

• products over reactants

• favorability of a reaction

chemical equilibrium equation

K_f / K_r

+K_eq

• products forwards

• favorable

-K_eq

• reactants forwards

• unfavorable

k_eq equation

e^-ΔG/T*T

ΔG with K_eq equation

-R*T*ln(K_eq)

Le Chatelier’s Principle

ball rolling on wood

• add more to one side, speeds up reaction on other side

• remove on one side, decreases reaction on other side

T in reactions

treat heat as Le Chatelier factor

gas in reactions

treat partial pressure as Le Chatelier factor

raising pressure of total system

• shifts to favor side with less mols gas

• think high to low diffusion

• not le chatelier

lowering pressure of total system

• shifts to favor side with more mols gas

• think inverse relationship

• not le chatelier

ox state of pure element or 2 of same

0

ox state of singular but charged atoms

charge

fc of species

sum of ox states

activation energy

E_a

r in pv=nrt equation

.08206 Latm / molK

neutral metals ox state

0

halogen (row before noble gases) ox state

-1

bond analysis more eN

-1

bond analysis less eN

+1

oxidation

loss of electrons

reduction

gain of electrons

OILRIG

ox is loss, red is gain

Oxidant

gained electrons

reductant

losses electrons