OCR A 5.1.2 How Far?

reversible reaction

reversible reaction

-where reaction can go back and for

for reaction

-initially reactants

-used up quickly but then slow as their conc drops

back reaction

-initially reactants are reformed slowly

-but then speed up as conc of products increases

what is red, green

red: forward reaction; reactants

green: backward reaction; products

dynamic equilibrium

-rate of for reaction = rate of back reaction

-conc of each substance remains constant

-only occurs in closed system

Kc

-equilibrium constant

-can be worked out from the molar conc in a reaction

kc of this

products/reactants

molar value = power

homogeneous reaction

all reactants and products in same state

homogeneous reaction and Kc

all reactants and products included in final Kc expression

heterogeneous reaction

all reactants and products in dif states

total pressure

sum of all pressures of individual gasses (partial pressures)

partial pressures

mol fraction of gas

Kp

-equilibrium constant for equil reaction involving gases

-parital pressure used to calc

Kp expression

Kp and heterogeneous equilibria

when doing equation only use gages

le chatelier’s principle

which way will poe shift if pressure goes up

-shoft to side with fewestr gas particles

if delta H is negative

reaction is exo

increase temp in exo reaction: what happens to poe

-shifts to left to favour endo side

temp and Kp

if temp causes poe to shift to right Kp will increase

if temp change causes poe toshfit to left Kp will decrease

pressure and Kp

no effect

catalyst and Kp

no effect

conc and Kp

no effect