Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SCH4U - Chem > 7.4 Qualitative Changes To Equilibrium > Flashcards

7.4 Qualitative Changes To Equilibrium Flashcards

1
Q

What happens when there’s a disturbance to equilibrium?

A

A new equilibrium will be established so that the rate of the forward reaction and reverse reaction is equal

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

What can disturb an equilibrium?

A

Pressure, temperature, concentration, or a combination of these

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

What is Le Chatelier’s Principle

A

When a chemical system at equilibrium is disturbed by a change in a property, the system will adjust to OPPOSE the change

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

What did Chatelier discover

A

That changing a property of a system creates a temporary “non equilibrium” state in the system, before a new equilibrium is established

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

How does ammonia synthesis use le Chatelier’s principle?

A

By increasing the pressure, equilibrium shifts to the right because it has fewer mols, so more ammonia is yielded

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

What happens to a chemical system if you increase pressure? decrease?

A
  • Increase: equilibrium shifts to side with fewer mols
  • Decrease: equilibrium shifts to side with more mols
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an equilibrium shift

A

A change in concentration of reactants and products to restore an equilibrium state

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

What happens if you remove reactants

A

Reaction shifts left

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

What happens if you add reactants

A

Reaction shifts right

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

Explain how in Fe + SCN <-> FeSCN more product can be yielded

A

By adding more of a reactant one at a time (for example SCN), it will combine with Fe to create more products and vice versa. Adding a reactant will shift the rxn to the right to yield more product.

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

What happens if you remove a product

A

Reaction shifts right

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

What happens if you add product

A

Reaction shifts left

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

Define collision theory

A

Entities in a chemical system must collide to react

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

What happens when you increase concentration of an entity according to collision theory

A

It will most likely collide with other entities since there is more present

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

What kind of collisions can potentially contribute to a reaction

A

Collisions between reactant entities

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

The more frequently collisions occur, the more likely a…

A

Reaction will take place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can collision theory tell us about a chemical reaction system

A

It can tell us how a system at equilibrium responds to changes in concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

More reactant added = (collision theory)

A

More successful collisions; forward reaction increases, reaction shifts right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

More product added = (collision theory)

A

More successful collisions; reverse reaction rate increases, reaction shifts left

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the rate of a chemical reaction reflect (collision theory

A

How often reacting entities are colliding (whether its reactants or products)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

If you increase the concentrations of the reactants, what happens to the rate of the forward reaction and how does the system compensate

A

The rate of the forward reaction increases, leading to more products yielded until the reverse reaction rate begins to increase until both rates are equal. The new equal rate is how the new equilibrium is established

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why do chemical engineers use Le Chatelier’s principle

A

To get a reaction to shift right to yield more product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is Chatelier’s used in:
3NO2 + H2O <-> 2HNO3 + NO

A

Since nitric acid is very useful, NO gets removed by reacting it with O2. Since its a product, the system shifts right so that more desired nitric acid is yielded

24
Q

How is Chatelier’s used in:
CO + H2O <-> CO2 + H2

A

In the gasification of carbon, it creates usable hydrogen fuel. More reactants get added to maximize yield of H2

25
Q

How is Chatelier’s used in:
Hb + O2 <-> HbO2

A

In the lungs, there is a high concentration of oxygen so the reaction shifts right to form HbO2 which gets pumped to the body cells with low concentrations of oxygen. The reaction shifts left so that the oxygen is released from hemoglobin for body cells to use.

26
Q

How is oxyhemoglobin formed?

A

From oxygen binding to hemoglobin

27
Q

What happens if an endothermic reaction loses energy?

A

The reaction is losing a reactant, so rxn shifts left and energy is released

28
Q

What happens if an exothermic reaction loses energy?

A

The reaction is losing a product, so rxn shifts right to make more products

29
Q

What happens if an endothermic reaction gains energy?

A

Reactant was added, rxn shifts right

30
Q

What happens if an exothermic reaction gains energy?

A

Product was added, rxn shifts left

31
Q

What is an ideal gas?

A

A hypothetical gas:
- made up of entities with no size
- travels in a straight line
- has no attraction to each other (no intermolecular forces)
- obeys all gas laws

32
Q

What does Boyle’s law state

A

As the volume of a gas changes, the pressure changes proportionally

33
Q

State example of Boyle’s Law

A

In a bicycle pump, decreasing volume of gas in the cylinder to a third of its size increases the pressure threefold

34
Q

What is partial pressure

A

The pressure that a gas in a mixture of gases would exert if it occupied the whole volume alone

35
Q

All the pressure in a bicycle pump is…

A

the sum of the partial pressures of the gases in the cylinder

36
Q

In ammonia synthesis, which side has more partial pressure of gas and why

A

The reactants, because there is 4 mols on the reactants side and 2 on the products

37
Q

If you reduce the volume of a container involved in NH3 synthesis, which change in concentration would be greater? why?

A

The change in concentration of reactants will be greater because it has more mols

38
Q

If volume was reduced, where would equilibrium shift? What is the purpose of the equilibrium shift here?

A

Since pressure would increase, and pressure shifts reaction to the side with fewer mols, rxn shifts right to reduce pressure in the system

39
Q

Why would we want to change an equilibrium system without affecting equilibrium position? Is it possible?

A

For efficiency and productivity of yielding desired products. Despite limitations on how much concentration, pressure, and temp can be changed, it is possible.

39
Q

How does a catalyst change an equilibrium system without affecting equilibrium position

A

It increases the reaction rates of both the forward and reverse reaction so that products are yielded faster

40
Q

How does an inert gas change an equilibrium system without affecting equilibrium position

A

Since inert gases are unreactive it will not enter a chemical rxn. Adding an inert gas to a gas mixture (with constant volume) increases pressure to regulate the system. And, since equilibrium depends on partial pressures and an inert gas doesn’t affect partial pressure, the equilibrium position is left unaffected.

41
Q

What is an inert gas

A

A noble gas with low reactivity since it has a full valence shell

42
Q

What happens to entities colliding with an inert gas? Does equilibrium shift?

A

It does not result in a chemical reaction but the inert gas can redirect the movement of the entity. The collision frequency of forward and reverse rxns remain unchanged so equilibrium does not shift

43
Q

How does the state of reactants affect equilibrium

A

Equilibrium can only be affected by concentrations of entities in the same states of matter as the substances in the system

44
Q

Why does solid iodine not have an affect on the equilibrium of::
H2 (g) + I2 (s) <-> 2HI (g)

A

We ignore solids and liquids when determining equilibrium because their concentrations are constant and do not affect the equilibrium expression.

45
Q

If K > 1, what is favored?

A

Products

46
Q

If K < 1, what is favored?

A

Reactants

47
Q

What happens to K if temperature increases in an endothermic reaction

A

K increases

48
Q

What happens to K if temperature increases in an exothermic reaction

A

K decreases

49
Q

What is the dependent variable

A

It is what’s being affected in an experiment
Example: When adding HCl to determine the affect on CuCl2, CuCl2 is dependent because it is being affected

50
Q

What is the independent variable

A

It is what’s being changed in an experiment
Example: When adding HCl to determine the affect on CuCl2, HCl is independent because we are testing its effect on CuCl2

51
Q

What’s a control

A

The experiment setup without any changes

52
Q

What happens to a system with equal mols of gas on each side if volume is changed

A

Pressure cannot be changed, so equilibrium remains unaffected

53
Q

Are liquids and solids affected by pressure changes

A

No

54
Q

Which way does a reaction shift if you add a catalyst

A

No shift, catalysts don’t affect equilibrium position

SCH4U - Chem (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions