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Chemistry - Year 12 > Module 5: Equilibrium and Acid Reactions > Flashcards

Module 5: Equilibrium and Acid Reactions Flashcards

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1
Q

What is entropy?

A

It is the measure of number of possible arrangements of a system

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2
Q

When can entropy increase?

A

When the volume increase, number of particles increases, temperature increases or there is a change in state

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3
Q

What is a spontaneous reaction?

A

Is a reaction that occurs on its own accord

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4
Q

When is a reaction spontaneous?

A

ΔG < 0

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5
Q

When is a reaction not spontaneous?

A

ΔG > 0

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6
Q

When is a reaction at equilibrium?

A

ΔG = 0

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7
Q

How do you calculate gibbs free energy?

A

ΔG = ΔH - TΔS

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8
Q

When is a reaction always spontaneous according to S and H?

A

ΔH < 0 (Exothermic) and TΔS > 0 (increase in entropy)

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9
Q

When is a reaction never spontaneous according to S and H?

A

ΔH > 0 (Endothermic) and TΔS < 0 (decrease in entropy)

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10
Q

When is a reaction spontaneous at high temperatures according to S and H?

A

ΔH > 0 (Endothermic) and TΔS > 0 (increase in entropy)

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11
Q

When is a reaction spontaneous at low temperatures according to S and H?

A

ΔH < 0 (Exothermic) and TΔS < 0 (decrease in entropy)

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12
Q

What are irreversible reactions?

A

Are reactions which occur in one direction

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13
Q

What are some examples of irreversible reactions?

A

Baking a cake
Combustion reactions
Combustion of magnesium and iron wool

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14
Q

What are reversible reactions?

A

Are reactions where the products formed can react again and reform the reactants

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15
Q

What are some examples of reversible reactions?

A

Evaporation and condensation of water
Formation of saturated sugar solution
Reaction between de/hydrated cobalt (II) chloride
Reaction between iron (III) nitrate and potassium thiocyanate

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16
Q

When is equilibrium reached in the evaporation and condensation of water?

A

When the rate of evaporation is equal to the rate of condensation

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17
Q

What colour is dehydrated cobalt (II) chloride?

A

Blue

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18
Q

What colour is hydrated cobalt (II) chloride?

A

Pink

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19
Q

What colour is a solution of iron (III) nitrate?

A

Pale yellow

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20
Q

What colour is a solution of potassium thiocyanate?

A

Colourless

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21
Q

What colour is iron (III) thiocyanate?

A

Deep red

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22
Q

What is chemical equilibrium?

A

When both reactants and products are in concentrations which have no further tendency to change with time

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23
Q

What is dynamic equilibrium?

A

When the rate of forward reaction and the rate of reverse reaction is equal

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24
Q

What is the Haber process?

A

The production of ammonia from hydrogen gas and nitrogen gas

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25
What is the extent of a reaction?
It is how much product has been formed when equilibrium is met
26
What are the three factors which affect collision theory?
1. Frequency of collisions 2. Orientation of the particles 3. Whether there is sufficient energy to break chemical bonds
27
What is static equilibrium?
When the rate of forward reaction and reverse reaction is almost zero
28
What is an example of static equilibrium?
carbon (graphite) <----> carbon (diamond)
29
What are non-equilibrium systems?
Reactions that never reach an equilibrium and are irreversible
30
What are some examples of non-equilibrium systems?
Combustion and photosynthesis
31
What is Le Chatelier's principle?
If an equilibrium system is subjected to a change or disturbance in conditions, the system will adjust itself to counteract and minimise the effect of change
32
How does increase in concentration of reactants impact equilibrium?
Forward reaction is favoured, equilibrium shifts to the right
33
How does increase in concentration of products impact equilibrium?
Reverse reaction is favoured, equilibrium shifts to the left
34
How does increase in pressure impact equilibrium?
Causes the equilibrium to shift towards the direction with less number of moles
35
How does decrease in pressure impact equilibrium?
Causes the equilibrium to shift towards the direction with more number of moles
36
How does decrease in volume impact equilibrium?
(Increases pressure) Causes the equilibrium to shift towards the direction with less number of moles
37
How does increase in volume impact equilibrium?
(Decrease pressure) Causes the equilibrium to shift towards the direction with more number of moles
38
When is a reaction exothermic?
ΔH = -ve
39
Which side is the energy on for exothermic reactions?
Product side
40
When is a reaction endothermic?
ΔH = +ve
41
Which side is the energy on for endothermic reactions?
Reactant side
42
How does increase of temperature impact equilibrium?
Causes the equilibrium to shift towards the direction which does not produce energy to use up the extra energy
43
How does decrease of temperature impact equilibrium?
Causes the equilibrium to shift towards the direction which produces energy to make up for the lost energy
44
What does a rate vs time graph look like?
Forward rate decreases, reverse rate increases until they meet in the middle
45
What does an amount vs time graph look like?
Reactants and products increase and decrease until they are both straight lines
46
What does a sharp peak on one chemical mean on a concentration equilibrium graph?
Change in concentrations
47
What does a sharp peak of all chemicals mean on a concentration equilibrium graph?
Change in pressure or volume
48
What does a smooth peak of all chemicals mean on a concentration equilibrium graph?
Change in temperature
49
How do you remember the equilibrium constant equation?
PORK product over reactant = Keq
50
What is the symbol of equilibrium constant?
Keq
51
What does the Keq indicate?
The equilibrium position
52
What does it mean if the Keq is greater than 1?
Equilibrium tends towards the products (right)
53
What does it mean if the Keq is smaller than 1?
Equilibrium tends towards the reactants (left)
54
What does it mean if the Keq is very large?
The reaction is near completion
55
What does it mean if the Keq very small?
The forward reaction hardly occurs
56
What is the only thing that can impact Keq?
Temperature
57
When is the Keq accurate?
When a system is at equilibrium
58
What is reaction quotient?
When the equilibrium expression is different to Keq
59
What is the symbol for the reaction quotient?
Q
60
What reaction favoured if Q>Keq?
The reverse reaction
61
What reaction favoured if Q
The forward reaction
62
What reaction favoured if Q=Keq?
The system is at equilibrium
63
What are the only things considered when calculating Q?
Gases and aqueous solutions
64
How does an increase of temp impact Keq of endothermic reactions?
Favours forward reaction hence Keq value increases
65
How does a decrease of temp impact Keq of endothermic reactions?
Favours reverse reaction hence Keq value decreases
66
How does an increase of temp impact Keq of exothermic reactions?
Favours reverse reaction hence Keq value decreases
67
How does a decrease of temp impact Keq of an exothermic reactions?
Favours forward reaction hence Keq value increases
68
What is the structure of water?
2 hydrogen bonds covalently bond to an oxygen atom
69
Are the covalent bonds in water polar or non-polar?
Polar
70
What bonds exist between water molecules?
Hydrogen bonds
71
When is a substance soluble?
When more than 0.1 mol of it will dissolve in 1L of water at 25*C
72
When is a substance insoluble?
When less than 0.01 mol of it will dissolve in 1L of water at 25*C
73
When is a substance slightly soluble?
When 0.01-0.1 mol of it will dissolve in 1L of water at 25*C
74
What does SNAAP stand for?
Sodium Nitrate Ammonium Acetate Potassium
75
What are the SNAAP salts?
Salts which are soluble
76
What is the solubility product?
Is the product of the concentration of ions in a saturated solution of a insoluble salt
77
What does Ksp include?
Only aqueous solutions
78
What is the ionic product?
The product of the concentration of ions in any solution
79
When is a solution saturated?
When the ionic product = Ksp
80
How does Ksp show solubility?
The bigger the Ksp the more soluble it is
81
When will a precipitate not form?
Ionic product < Ksp
82
When will a precipitate form?
Ionic product > Ksp
83
Why is the undissolved solid not included in the Ksp calculation?
As it remains constant and there is no change in concentration
84
What is Kc?
It is like the Keq
85
What happens to the Kc when all moles are halved, doubled, tripled etc?
Kc to the power of what happened eg if halved Kc to the power of half
86
What happens to the Kc when the reaction is reversed?
It will be Kc to the power of a negative
87
What is Kp and how do you calculate it?
It is the equilibrium constant based on pressure and it is calculated the same way as Keq but with the pressures
88
How to calculate Ksp from molar solubility?
1. Write balanced equation A ⇌ B + C 2. Ksp = [B][C] 3. Substitute molar solubility in and if required multiply by the number of ions produced
89
What is a homogeneous equilibrium?
Is a reaction where all of the products and reactants are the same state
90
What is a heterogeneous equilibrium?
Is when there are different states in the reaction
91
Is the self-ionisation of water exothermic of endothermic?
Endothermic
92
How do you find concentration from Ksp?
Use a rice table and solve for x
93
Is the statement [H3O+] = [OH-] always true?
Yes at all temperatures pure water will always have [H3O+] = [OH-]
94
How does the addition of a catalyst affect a reversible reaction?
It decreases the activation energy of both the forward and reverse reaction

Chemistry - Year 12 (5 decks)

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