chemical equilibrium Flashcards
1
Q
Closed system
A
- a system in which mass is conserved inside the system but energy can enter or leave the system freely
2
Q
Open system
A
- a system in which both energy and matter can be exchanged between the system and its surroundings
3
Q
forward vs. reverse reaction
A
- products can be produced into products
- products can be produced back into products
4
Q
dynamic chemical equilibrium
A
- forward and reverse reactions are taking place at the same rate
- constant concentration
- closed system and reversible reaction must exist
- rate of forward reaction = rate of reverse reaction
5
Q
Le Châteliers principle
A
- When an external stress (change in pressure, temperature or concentration) is applied to a system in dynamic chemical equilibrium, the equilibrium point will change in such a way as to counteract the stress
6
Q
phase equilibrium
A
- a state of dynamic equilibrium between liquid and vapour faze
7
Q
equilibrium state
A
- dynamic, not stopped and both reactions occur at the same rate
- closed system
- concentrations remain constant
- looks as if reaction has stopped, but is continuous
- reached from either direction
8
Q
Le Châteliers principle steps
A
- identify disturbance
- state system will oppose disturbance
- forward or reverse is favoured
- result, observation
9
Q
concentration changes
A
- solvent and solution (solid won’t change, pure liquid density won’t change)
10
Q
pressure
A
- only applies to gasses (any gas in either of the reactions)
- larger volume (increase) = less pressure (decrease), more moles of gas
- lesser volume (decrease) = more pressure (increase), less moles of gas
- increase in pressure due to decrease in volume
- side with less moles is favoured
- forward or reverse is favoured
- yield of favoured is increased
- new equilibrium is formed
11
Q
temperature
A
- increase
- shift to side that opposes
- endothermic is favoured
- decrease
- shift to side that opposes
- exothermic is favoured
12
Q
catalyst
A
- increases rate of reaction
13
Q
LCP
A
- stress
- counter
- favoured reaction
- result
14
Q
Kc effects
A
- temperature
- no effects
- pressure
- concentration
15
Q
concentration increase (rate time graph)
A
- substance increase
- opposes this decreasing amount of substance
- see and increase in other substance
- gradually increases until equal again
16
Q
change in pressure (rate time graph)
A
- sharp increase / decrease in all substances
17
Q
change in temperature (rate time graph)
A
- affects either endothermic or exothermic
18
Q
catalyst (rate time graph)
A
- increase both rates
19
Q
change in concentration (concentration time graph)
A
- sharp change
- gradual change in other substance till equilibrium
20
Q
change of temperature (concentration time graph)
A
- sharp change
- one of either the products or the reactants changed in one direction the other in the other direction
21
Q
catalyst (concentration time graph)
A
- no change if at equilibrium already
