Chemistry 1B

Forward Reaction

Products only

Reverse Reaction

Reactants only

Dynamic Equilirbium

Forward reaction = Reverse reaction

equilibrium expression

K= ([product1]^(coefficient) X [product2]^(coefficient))/([reactant1]^(coefficient) X [reactant2]^(coefficient))

What states of matter should be included in equilibrium expression?

Aqeous, gas

What states of matter should NOT be included in the equilibrium expression?

Solids, liquids

If K = 1

Reaction doesn't favor either side

If K>1

Reaction is product favored

If K

Reaction is reactant favored

If K>10^10

Reaction is NOT reversible

If K

No reaction

You can use the equilibrium expression for what quantities?

Partial pressure and concentrations

Molarity equation

M= n/V

moles equation

n = PV/RT

Partial pressure and concentration equilibrium values

Kp = Kc (RT)^Δn

K relationships: Rxn reversed

Inverted K (1/K)

K relationships: rxn multiplied

Raise K by factor (K^x)

K relationships: Rxn divided

Root K by factor (x√K)

2+ Reactions added

Multiply K values (K1*K2)

Lechatliers Principle

If rxn is disturbed, it will shift to a new equilibrium

What is RDS

The slowest reaction is the Rate Determining Step in a series and determines rate law

Molecularity

number of molecules involved

Activation energy and RDS

RDS will have the highest activation energy

What does Rate law do?

Shows relationship between rate of rxn and concentration

How is Rate law determined

experimentally ONLY

Rate law equation

rate = K [A]^m[B]^n[C]^c (m,n,c determined experimentally)

If:
A+B +C -> product
And you know:
rate =[A]^1*[B]^2*[C]^0
What happens if you double A?

Rate X 2

If:
A+B +C -> product
And you know:
rate =[A]^1*[B]^2*[C]^0
What happens if you double B?

Rate X 4

If:
A+B +C -> product
And you know:
rate =[A]^1*[B]^2*[C]^0
What happens if you double C?

no effect

If:
A+B +C -> product
And you know:
rate =[A]^1*[B]^2*[C]^0
What happens if you double A,B, and C?

Rate X 8

What is the rate of chemical reactions?

How fast reactants make products

what happens to the concentration of a reactant over time in a reaction?

Concentration lowers over time

How to find instantaneous rate of change of a reactant? products??

Rate = -1/coefficient * (change in concentration)/(change in time)

What are the three techniques used to monitor reaction mixtures?

Polarimetry, spectrophotometry, pressure measurement

What raises rate of reaction?

↑ Temperature, ↑pressure, ↑Concentration, ↑ volume, ↑ surface area, + catalyst

integrated rate law

Equation showing relationship between concentration and time

First order integrated rate law

ln[A] = -K*t*ln[Ἁ]

Second order integrated rate law

1/[A] = K*t + 1/Ἁ

Zero Order Integrated Rate Law

[A] = -K*t + Ἁ

Half life of zero order

Ἁ/2K

Half life of first order

0.693/K

Half life of second order

1/KἉ

Temperature effect on Rate equation

ln(K) = -(Ea/R)*(1/T)+ln(A)
Ea= Activation energy
T = temperature
R = 8.314 (gas constant)
A = frequency factor