Equilibrium 2 Flashcards
state le chatelier’s principle
If an exteneral stress is applied to a system in equalibirum, then the system will rearrange itself so as to nullfy/counteract/ remove the stress and achieve a new equilibrium
give the effects of change in concentration on the reaction and equilibrium:
(i) increase in conc of product
(ii) decrease in conc of product
(iii) increase in conc of reactnat
(iv) decrease in conc of reactant
(i) backward reaction to give reactant
(ii) forward reacn to give more priduct
(iii) forward racn to give more product
(iv) backward reacn to give reactants.
“When the concentration of any of the
reactants or products in a reaction at
equilibrium is changed, the composition
of the equilibrium mixture changes so as
to minimize the effect of concentration
changes”
what are the commercial applications of change in concentration
we can say
that removal of a product also boosts the
forward reaction and increases the
concentration of the products and this has
great commercial application in cases of
reactions, where the product is a gas or a
volatile substance.
In case of manufacture of
ammonia, ammonia is liquified and removed
from the reaction mixture so that reaction
keeps moving in forward direction.
Similarly,
in the large scale production of CaO (used as
important building material) from CaCO3
,constant removal of CO2
from the kiln drives
the reaction to completion.
It should be
remembered that continuous removal of a
product maintains Qc
at a value less than Kc
and reaction continues to move in the forward
direction.
effect of pressure on the equilibrium :
(i) increase in pressure
(ii) decrease in pressure
(iii) increase in volume
(iv) decrease in volume
(i) the reaction shifts to the side where there are less no of moles
(ii)the reaction shifts to the side where there are more no of moles
(iii) the reaction shifts to side where tthere are more no ofmols( due to decrease in pressure
(iv) the reacn shifts to the side with fewer no of moles( due to increase in pressure)
what will happen if we add inert gas to reaction mixture
If the volume is kept constant and an inert gas
such as argon is added which does not take
part in the reaction, the equilibrium remains
undisturbed. It is because the addition of an
inert gas at constant volume does not change
the partial pressures or the molar
concentrations of the substance involved in the
reaction. The reaction quotient changes only
if the added gas is a reactant or product
involved in the reaction
what will happen to quilibrium constannt if temperature is change
(i) is temperature increase
(ii) temperature decrease
(i) for endothermic reacn, if heat increases, then it will absorb more heat so K increases. so forward reacn will occur
For exothermic reaction, if heat increases, then it will absorb more heat, so K decreases because backward reacn will ocur
(ii) for endothermic reacn, if heat decreases, then it wil release heat so K decreases because backward reac will occur
for exothermic reacn, if heat decreases, then it will release heat so K increases because forward reacn will occur
if the forward reacn is endothermic then backward is exothermic and vice versa
give example of change in reacn constant
Effect of temperature can also be seen in
an endothermic reaction,
[Co(H2O)6]3+aq) + 4Cl-(aq)⇌ [CoCl4]2–(aq) +6H2O(l)
pink colourless blue
At room temperature, the equilibrium
mixture is blue due to [CoCl 4] 2–. When cooled
in a freezing mixture, the colour of the mixture turns pink due to [Co(H2O)6] 3+
what is the effect of catalyst
A catalyst increases the rate of the chemical
reaction by making available a new low energy
pathway for the conversion of reactants to
products. It increases the rate of forward and
reverse reactions that pass through the same
transition state and does not affect
equilibrium. Catalyst lowers the activation
energy for the forward and reverse reactions
by exactly the same amount. Catalyst does not
affect the equilibrium composition of a
reaction mixture.
