The partial pressure of a gas in a mixture is
the pressure that the gas would have if it alone occupied the volume occupied by the whole mixture.
If a mixture of gases contains 3 different gases then the total pressure will equal the 3 partial pressure added together
equation
P =p1 + p2 + p3
partial pressure =
word and symbol
mole fraction x total pressure of gas 1
p1 = x1 P
mole fraction =
number of moles of a gas/ total number of moles of all gases
moles of reactant at equilibrium =
initial moles – moles reacted
moles of product at equilibrium =
initial moles + moles formed
the techniques and procedures used to
determine quantities present at equilibrium
titrations and using colorimeter
expressions for Kc and Kp for homogeneous and heterogeneous equilibria
homogenous equilibrium-> involved reactants are in the same state
heterogenous equilibrium-> molar concentrations for solids and pure liquids do not change because volume is constant. so concentrations of pure solids and liquids are not included in Kc
The larger the Kc the greater the
amount of products.
If Kc is small we say the equilibrium favours the reactants
if K is… =,> or <
K= 1, position of equilibrium halfway between products and reactants
K>1= product side is favoured
K<1= reactant side is favoured
Kc and Kp only change with
temperature
Changing concentration would shift the position of equilibrium but
the value of Kc would not change.
Catalysts have no effect on the value of Kc or Kp or the position of equilibrium because
they speed up both forward and backward rates by the same amount.
exothermic reaction, increasing temperature will mean
less yield as equilibrium moves to the left(reactants) to lower temperature
endothermic reaction, increasing temperature will mean
more yield as equilibrium shifts to the right(products) to increase temperature
Increasing pressure does
not change Kc.
The position of equilibrium will change if(kp and pressure)
pressure is altered but the value of Kp stays constant as Kp only
varies with temperature
Kp expressions only contain
gaseous substances. Any substance with another state is left out
mole fraction definition
is a measure of how much of a given substance is present in a reaction mixture