Kc and Le Chatelier's Principle Flashcards

1
Q

What is the definition of dynamic equilibrium

A

•dynamic: the rate of forwards reaction= the rate of backwards reaction
•equilibrium: the concentrations of products and reactants are constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is dynamic equilibrium reached? (3m)

A

•at the start, the forwards reaction is fast and the backwards reaction is slow
•after the start, the forwards reaction slows and the backwards reaction speeds up
•the rates become equal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a closed system

A

Carried out in a sealed container

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why are closed systems used

A

So no products escape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

On equilibrium graphs, where I’d dynamic equilibrium reached

A

When the reactants and products are constant
(Both straight horizontal lines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which way does equilibrium shift for products and reactants to “cross” on the graph

A

To the right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which way does equilibrium shift for products and reactants to never meet on the graph

A

To the left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

State Le Chateliers principle

A

The position of equilibrium will always shift to oppose any changes made to it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What can affect position of equilibrium

A

•concentration
•temperature
•pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which way does equilibrium shift when conc of reactants increases

A

To the right
To oppose increase in concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is yield of products affected when conc of reactants increases and why

A

Equilibrium shifts to the right to oppose conc increase
Yield increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which way does equilibrium shift when pressure increases
2reactants –> 1product

A

Fewer moles on right
Equilibrium shifts to the right to oppose pressure increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When can pressure affect equilibrium

A

Gaseous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which way does equilibrium shift when pressure increases
3reactants –> 3products

A

No change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

If reaction is endothermic, which way does equilibrium shift when temperature increases

A

Forwards reaction is endothermic
Equilibrium shifts to the right to oppose increase in temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a catalyst

A

Speeds up the rate of reaction
By providing an alternate reaction pathway
With a lower activation energy

17
Q

How does a catalyst work when added to equilibrium

A

•forwards and backwards reaction increase equally
•no change in position to equilibrium
•dynamic equilibrium is reached faster

18
Q

What are the ideal conditions of the harder process

A

400atm
350°c

19
Q

Why are ideal conditions of the harder process not used in the industry

A

High pressure is too expensive

20
Q

What are the compromised conditions of the harder process

A

200atm
450°c

21
Q

What catalyst is used in the harber process

A

Iron

22
Q

What is the formula for Kc

A

[Products]/ [reactants]

23
Q

When Kc>1 equilibrium shifts to the…

A

Right

24
Q

When Kc<1 equilibrium shifts to the…

A

Left

25
Q

What happens when your units cancel out when calculating Kc

A

NO UNITS

26
Q

What must you always consider when calculating Kc

A

If moles are in equilibrium
(Use an ice box)

27
Q

When do you not need to calculate concentration

A

Number of reactions=number of products
Volumes cancel out