Chemical Equilibrium

Question 1

define reversible reaction?

Question 2

what is chemical equilibrium?

Answer 2

a state of chemical reaction in which forward & reverse reactions take place at the same rate.

Question 3

why is chemical equilibrium called dynamic equilibrium?

Question 4

state law of mass action?

Question 5

define active mass?
expressed in? and unit

Answer 5

represents the concentartion of reactants & products in
mol.dm-3
[ ]

Question 6

what is kc & what does subscript c denotes?

Answer 6

equilibrium constant which is defines as the product of the conc. of products to the product of the conc. of reactants eash raised to the pwr = to the coefficient in the balanced chemical equation
kc is dependent upon temp. & independent of the initial concentration of reactants
molar concentration at equilibrium

Question 7

kf and kr?
derive equilibrium constant expression? what does the brackets indicate?

Answer 7

rate constants for forward & reverse reactions
active mass

Question 8

conditions for equilibrium?

Question 9

ways to recognize equilibrium?

Question 10

unit of equilibrium constant?

Answer 10

may or may have units
depend upon the form of equilibrium expression

Question 11

when does Kc have no units?

Answer 11

when the total no. of moles of reactant = total no. of moles of products in balanced chemical equation

Question 12

when does Kc have unit?

Answer 12

when the total no. of moles of reactant is different from total no. of moles of products in balanced chemical equation

Question 13

how to find equilibrium constant unit?

Answer 13

write equilibrium constant expression
write units

Question 14

what is Haber process?

Answer 14

By reacting nitrogen with hydrogen at 400 degrees and 200 atm pressure in the presence of catalyst, Haber process yields ammonia. this is a reversible process and produces only 33% Ammonia at equilibrium
high pressure is used to favor the formation of ammonia then cooling the equilirbrium mixture gives 98% ammonia.

Question 15

what is contact process?

Answer 15

sulphuric acid is produced on a large scale by the contact process in this process sulphur is converted into SO2
Sulphur dioxide is purified & further oxidized at 450 degree Celsius & 200 ATM pressure in the presence of Pt or V2O5 as catalyst.
SO2 + O2 = SO3 (reversible)
SO3 is then converted into 100% pure sulphuric acid.

Question 16

Le Chatellier’s law?

Answer 16

if you impose a change in conc, temp, or pressure on a chemical system at equilibrium, the system responds in a way that opposes the change.

Question 17

what conditions tend to increase the yield of NH3 & SO3 to about 98%?

Answer 17

first equilibrium is established in the presence of catalyst in minimum time
& then by increasing the pressure & decreasing the temperature equilibrium is shifted towards right.

Question 18

importance of equilibrium constant?

Question 19

in an Irreversible reaction equilibrium is ________?

Answer 19

never established

Question 20

will a reaction ever stop at equilibrium state?
At equilibrium state, concentration of reactants and products do/ do not change.

Answer 20

At equilibrium state, a reaction does not stop.
At equilibrium state, concentration of reactants and products do not change.

Question 21

describe the macroscopic characteristics of an equilibrium reaction?