Chem Exam 2

exothermic equation

Ea’ = Ea + △H

endothermic equation

Ea’ = Ea - △H

Arrhenius Equation

K = A x e ^ (- Ea/RT)

slope equation

-Ea/RT

△n

(# of molds of gaseous products) - (# of mols of gaseous reactants)

what is K

Rate constant or Equilibrium constant

What is A

frequency factor

what is a frequency factor

the number of effective collisions

What is Kf

rate constant for the forward reaction

what is Kr

rate constant for the reverse reaction

what is Q

reaction quotient, moving value not in equilbrium

what increases the rate of a reaction

increase of temperature

increase of concentration increases

rate

homogenous

catalyst is same phase as reactant

heterogenous

catalyst is different phase as reactants

absorption

penetrates

adsorption

does not penetrate the surface

each step reaction in a reaction mechanism is called a

elementary reaction

order of elementary reaction depends on the

coefficient of reacting species

reaction intermediate

a substance that is produced and consumed during the course of the reaction and never shows up as a product (can be used to identify)

slowest step in the reaction mechanism is called the

rate-determining step

rate of reaction depends on the

rate of the slowing step

a reaction is said to be in a state of equilibrium when

rate of the forward reaction is equal to the rate of the reverse reaction

at equilibrium, the ratio of product to reactant concentrations, all raised to appropriate exponents is

constant at constant temperatures

Q is at

any time

K is at

equilibrium

Q = K

reaction is in equilibrium

Q > K

reaction moves at a faster rate in the reverse direction

Q < K

reaction moves at a faster rate in the forward direction

Q or K =

Products / Reactants

(s) (l)

value is 1 and is left out

(g) (aq)

only these are included

Le Chatelier’s Principle of Mobile Equilibrium

if a reaction in equilibrium is disturbed the equilibrium will shift in a direction to counter that disturbance

yield will increase if

reaction moves towards the products (right)

what would happen if △H is +

the reaction would move to the right

What does reaction equilibrium favor if K = 1

none

What does reaction equilibrium favor if K > 1

products

What does reaction equilibrium favor if K < 1

reactants

energy of activation

the minimum amount of energy required to initiate a chemical reaction

inhibitor

raises energy of activation of a reaction

catalyst

lowers energy of activation of a reaction

Collision Theory of Reaction rate (1)

reactants must collide

Collision Theory of Reaction rate (2)

collisions must occur with proper orientation of bonds, molecules

Collision Theory of Reaction rate (30

collision must occur with certain minimum energy called Energy of Activation (Ea)