Topic 10 - Equilibrium I Flashcards
What is a reversible reaction?
A reaction that can go forward or backwards.
How do you show a reversible reaction in an equation?
Use an double arrow that points both ways in the equation.
See pg 118 of revision guide
What is dynamic equilibrium?
When the concentrations of reactant and products in a reversible reaction are constant, and the forward and backwards reactions happen at the same rate.
In dynamic equilibrium, what can be said about:
• The reaction rates
• The concentrations
- The forward and backwards reactions happen at the same rate
- The concentrations of the products and reactants stay constant (but not necessarily equal to each other)
In dynamic equilibrium, when there are more products than reactants, where does the position of the equilibrium lie?
To the right.
In dynamic equilibrium, when there are more reactants than products, where does the position of the equilibrium lie?
To the left.
Describe how dynamic equilibrium is reached from a system with just the reactants in at first.
- As the reactants get used up, the forward reaction slows down
- As more product is formed, the reverse reation speeds up
- Eventually, the two happen at the same rate and dynamic equilibrium is reached
Where can a dynamic equilibrium be reached?
In a closed system.
What is the equilibrium constant?
A measure of how far to the left or right the equilibrium is in a particular system.
What is the symbol for the equilibrium constant?
Kc
‘c’ is subscript
What is a homogeneous system?
One in which everything is in the same physical state,
What is a heterogeneous system?
One in which not everything is in the same physical state.
In a homogeneous system, which reactants and products are used in the equation for Kc?
All of them.
Write an equation for Kc for the reaction:
aA + bB dD + eE
Kc = [D]^d [E]^e / [A]^a [B]^b
In the equation for Kc, what goes on the top and bottom?
Top: Products
Bottom: Reactants
In the equation for Kc, what do the square brackets and powers mean?
- Square brackets: Concentration of each substance.
* Powers: Number of moles of each substance from equation.