Unit 3 Chapter 2: Chemical equilibrium Flashcards
Closed system
only energy, not matter, is exchanged with the surroundings
Open system
both matter and energy exchanged between the system and surroundings
Reversible reaction
reaction in which products can react together to be converted back to reactants (shown by a double arrow)
Irreversible reaction
reaction in which products cannot react together to be converted back to reactants
Dynamic Equilibrium
the point reached by a reversible reaction where the rate of the forward and reverse reaction is equal
Equilibrium can only be achieved in a closed system? Yes or No
Yes
Different reactions proceed to different extents therefore?
the ratio of reactants to products at equilibrium is different for different reactions
Equilibrium yield
indicates how much product is formed at equilibrium
Reaction rate
measure of the change in the concentrations of the reactants and products with time
Le Chatelier’s principle
if an equilibrium system is subject to change, the system will shift to partially oppose the change
Adding more reactant causes:
Equilibrium shift to the products
Adding more product causes:
Equilibrium shifts to the left
Decreasing pressure (increasing volume) causes:
Equilibrium shifts in direction of most particles
Adding inert gas (constant volume) causes:
No change
Adding water (dilution of solution) causes:
Shifts in direction of most particles
Increasing temperature (exothermic) causes:
Equilibrium shifts towards the reactions
Increasing temperature (endothermic) causes:
Equilibrium shifts towards the products
Adding a catalyst causes:
No change
Equilibrium constant (Kc):
The constant for a particular chemical reaction at a particular temperature; provides a measure of the extent of reaction and the relative concentrations of reactants and products at equilibrium
Kc > 10^4
almost complete reaction occurs
Kc < 10^-4
negligible reaction occurs
Kc =
[P]/[R]
Reaction quotient (Qc):
can be calculated for any stage of a chemical reaction
Qc < Kc
reaction must shift to the right to reach equilibrium
Qc = Kc
reaction has reached equilibrium
Qc > Kc
reaction must shift to the left to reach equilibrium
