Chem eqm Flashcards
Irreversible
- Chem rxn taking place in 1 direction only
- Limiting reagant present
3.Chem rxn goes to completion and only produced at the end
Reversible
- Chem rxn takes places in 2 directions
- No limiting reagent
- Chem rxn does not go to completion
- Forward and backward rxns take place simultaneously both reactants and products remain at the end
Arrow
Reversible
2 half arrows pointing in opposite directions
Irreversible
Full arrow pointing in only one direction
Types of equilibrium
1.Static
2.Dynamic
Static
No movement
Rate of forward and backward rxns =0
Occurs when there ix no exchange between reactants and products
E.g.: C(graphite) To C (diamond)
Dynamic
- Opposing movements at same rate
- Achieved in a closed system/vessel
3.Rate of forward= rate of backward
4.concentration of reactants and products do not change
Conc & rate graphs of dynamic eqm
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Kc formula
[C]^c[D]^d /[A]^a[B]^b where C and D are products and A and B are reactants
All of them are raised to their stochiometric ratio
What does Kc mean
Kc is an eqm constant representing the ratio of eqm conc of prod to reactants. It is only affected by temperature
Things that are not included
Solvents such as water not included as change in their concentration is negligible as they are present in large excess.
Solids are not included as their conc=density remains rather constant since vol and mass decrease proportionally hence density/conc remains unchanged
Kp formula
(PC)^c (PD)^d/(PA)^a (PB)^b
P is partial pressure
Partial pressure formula
PA= nA/ntotal x Ptotal
What is Kp
Ratio of eqm partial pressure of products to reactants
Le Chatelier’s Principle
A system @ eqm when subjected to change will shift its POE to partially oppose effect of change in order to reach new eqm
POE
proportion of products to reactants in an eqm mixture
Conc change
effect on POE
Effect of partial pressure
on POE
Effect of temp
on POE
How graph reflects changes in conc/partial pressure when
1.when reactants added
2. Reactants change
3.Products change
Extent of change depends on stochiometric ratio
Catalyst on Kc/Kp
the use of a catalyst does not in anyway affect the value of Kc/Kp
It allows for the eqm to be established more rapidly
E.g. Finely divided iron in haver process
Haber Process
🔺 H <0 N2+3H2 –>(half arrow reversible) 2NH3
Low temp to increase rate of forward rxn at 450C
Pressure High to increase forward rxn at 250atm
Rate of haber increase
High conc of N2 and H2
Using finely divided Fe catalyst
Yield of haber increase
continuous flow process ,NH3 continuously removed as it forms
