Chemical Equilibria Flashcards
What is the definition of reversible
A reaction which goes in both forward and backwards directions
What is the definition of equilibrium
A reversible reaction in which the amount of each reactant/product remains constant
What is the definition of dynamic equilibrium
Rate of forward reaction is equal to the rate of backwards reaction
What are the three characteristics of the equilibrium star
Closed system
Both forward and backwards reactions
Dynamic
What are the two types of chemical equilibria
Homogeneous and heterogeneous
What is the definition of homogeneous equilibria
A reaction in which all the reactants and products are in the same physical state
What is the definition of heterogeneous equilibria
A reaction in which all the reactants and products are not in the same physical state
What is the equilibrium constant
Kc = [products]
—————
[reactants]
What does the number of moles in the equation represent in the equilibrium constant
The power
What does the equilibrium constant indicate and what is the only thing it depends on
Indicates how far the equilibrium is over to the rhs
Depends on temperature
What is Le Chatelier’s Principle
When a change is imposed on a system in equilibrium the system tends to adjust so as to minimise the change
What does the position of equilibrium mean
Proportion of reactants and products in the equilibrium system
What does a large Kc indicate
The position of equilibrium is to the rhs
What does a low Kc indicate
The position of equilibrium is to the lhs
How do you know when equilibrium has been achieved
Colour stays the same
What effect does a change in pressure have on solid liquid and gas
No effect in solid or liquid
In gas it moves to side with fewer molecules - if number of moles is the same then no effect on equilibrium
What effect does increase and decrease in temp have on the position of equilibrium
⭕️ Increase - shift in direction of endothermic process
⭕️ Decrease - shift in direction of exothermic process
What effect does a change in concentration have on the position of equilibrium
⭕️ Increase reactants - shift to rhs
⭕️ Increase products - shift to lhs
What effect does the presence of a catalyst on the position of equilibrium
No effect on position
What is the equation and conditions for the Haber process
See notes for equation Conditions: - 450°C - compromise temp - 200atm - favour NH3 production - iron catalyst - equilibrium attained more quickly
What is the equation for the contact process
See notes for equation Conditions: - 450°C - compromise temp - 2atm - favour SO3 production - V2O5 catalyst - equilibrium attained more quickly
