Midterm review- Equilibrium Flashcards
Chemical Equilibrium
state of dynamic equilibrium that occurs in a closed system when the forward and reverse reactions of a reversible reaction occur at the same rate
Steps in EQ reaction
- Forward reaction occurs rapidly
- Reverse reaction cannot occur at first due to lack of products
- C and D start to form
- Reverse reaction slowly begins to occur
- Rate of both reactions become equal, concentrations of reactants and products becomes equal
- Equilibrium is established
Forward rate
Kf [A][B]
Reverse rate
Kr [C][D]
Mass Action Expression
[C][D] / [A][B]
Kc >1
Products are favored, EQ lies on right side
Kc < 1
Reactants are favored, EQ lies on left side
Large Kc
Reaction goes to completion
Small Kc
No reaction
What is omitted from Mass Action Expression?
Pure solids and liquids
Le Chatelier’s Principle
“If a change is made to the conditions of a chemical equilibrium, then the position of the equilibrium will readjust so as to minimize the change made.”
Increase concentration @ EQ
EQ moves to opposite side
Decrease concentration @ EQ
EQ moves to same side
Increase pressure @ EQ
EQ shifts to side with least moles of gas
Decrease pressure @ EQ
EQ shifts to side with most moles of gas
