Chemical equilibrium + Stoichiometry Flashcards

1
Q

What is the definition of Equilibrium?

A

An Equilibrium is a balanced state of constant change in a system.

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2
Q

What is the Equilibrium Law?

A

The equilibrium law states that, for a reversible system, a constant tells us how far the reaction has gone to the right-hand side, by the time equilibrium has been established.

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3
Q

What is the formula associated with Equilibrium law?

A

A+BC+D, the equilibrium constant is given by: K=.

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4
Q

What is le Chatelier’s principle?

A

This principle states that if a system in equilibrium is subjected to a stress, then the system will alter so as to oppose the effect of the stress.

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5
Q

What are the four types of stress?

A
  • Concentration of reactants / products.
  • Temperature
  • Pressure
  • Catalysts
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6
Q

What happens if you change the conditions of a reaction at equilibrium?

A

The reaction readjusts itself to relieve the stress.

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7
Q

Which type of reactions does pressure only have an effect on?

A

Gaseous reactions

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8
Q

What prediction can be made of gaseous reactions in relation to Le Chatelier’s Principle?

A

An increase in pressure will favour the reaction which reduces the volume (ie towards the side with the smaller number of molecules).

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9
Q

What do Catalysts do in relation to chemical reactions?

A

Catalysts increase or decrease the rate of the forward and backward reaction by the same amount.

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10
Q

When an increase of pressure is applied, what is the systems response?

A

The equilibrium shifts to the side with a lower amount of molecules.

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11
Q

When an decrease of pressure is applied, what is the systems response?

A

The equilibrium shifts to the side with a higher number of molecules.

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12
Q

When an increase of temperature is applied, what is the systems response?

A

An endothermic reaction is favoured.

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13
Q

When an decrease of temperature is applied, what is the systems response?

A

An exothermic reaction is favoured.

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14
Q

When an increase of concentration of ‘x’ is applied, what is the systems response?

A

A reaction in which ‘x’ is removed is favoured.

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15
Q

When an decrease of concentration of ‘x’ is applied, what is the systems response?

A

A reaction in which ‘x’ is formed is favoured.

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16
Q

What type of catalyst does the Haber Process use?

A

It uses an Iron catalyst.

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17
Q

Is the Haber Process Exothermic or Endothermic?

A

It is exothermic in its forward reaction.

18
Q

What is the chemical equation for the production of ammonia?

A

N2 + 3H2 <=> 2NH3

19
Q

Where is most ammonia made in Ireland?

A

It is mainly produced in the IFI Plant in Cobh, Cork.

20
Q

Will increased or decreased pressure favour the production of ammonia (N2 + 3H2 <> 2NH3)? Explain why.

A

Increased pressure will favour the production of ammonia because of the four molecules on the left and the two molecules on the right.

21
Q

Name one problem with keeping pressures high in the production of ammonia.

A

Keeping high pressures is expensive.

22
Q

In the production of ammonia, what is the pressure that is kept? Why?

A

It is kept at 200 atmospheres because it is the most cost effective and safe.

23
Q

Will increased or decreased temperature favour the production of ammonia?

A

Lowering temperatures will favour the production of ammonia but too low of temperatures can slow down production too much.

24
Q

What temperature does the producing of ammonia using Haber Process normally take place at?

A

500*C

25
Q

In relation to the Haber Process, which types of temperatures and pressure are favoured?

A

The Haber Process favours high pressures and low temperatures.

26
Q

Is the forward reaction of Contact Process exothermic or endothermic?

A

It is exothermic.

27
Q

What is the equation for the formation of sulphuric acid?

A

2SO2 + O2 2SO3

28
Q

Does the process for forming sulphuric acid favour increased or decreased pressures? Explain why.

A

It favours increased pressure for production of 2SO3 because of the three molecules on the left and the two molecules on the right.

29
Q

What is the pressure that is normally maintained during the Contact Process? Why.

A

Atmospheric pressure is normally maintained during this process because it is the most cost effective.

30
Q

Will increasing or decreasing temperatures during the Contact Process favour the production of 2SO3?

A

Decreasing the temperatures will favour the production of 2SO3.

31
Q

What temperature is normally maintained during the production of 2SO3?

A

450*C

32
Q

What is Kc?

A

The equilibrium constant (Kc) indicates the extent to which the reaction has ‘gone to completion’.

33
Q

What does a larger Kc value mean?

A

The larger the Kc value, the more that the reaction has gone to completion.

34
Q

Turn “A + B <> C + D” into the equilibrium constant equation.

A

Kc = [C][D]/[A][B]

35
Q

What is the empirical formula?

A

It is the formula of a compound that shows only the ratio in which the different types of atoms are present in the molecule.

36
Q

What is a molecular formula?

A

The molecular formula of a compound indicates the number of atoms of each kind in the molecule.

37
Q

What is the structural formula?

A

The formula of a compound showing the way in which the atoms are arranged in the molecule.

38
Q

Name the 7 diatomic elements.

A
  • Hydrogen
  • Nitrogen
  • Fluorine
  • Oxygen
  • Iodine
  • Chlorine
  • Bromine
39
Q

What is diffusion?

A

The spontaneous spreading out of a substance and is due to the natural movement of its properties.

40
Q

How do you find the percentage yield?

A

(Actual yeild / theoretical yeild) x 100

41
Q

What is chemical equilibrium?

A

Chemical Equilibrium refers to the state in a reversible reaction when the rate of the forward is equal to the rate of the backwards reaction.