Chemical Equilibrium, Le Chatelier's Principle And Kc Flashcards

1
Q

Some reactions are reversible
What is a reversible reaction
How is energy transferred

A

A reversible reaction is when the products can react to form the original reactants
The same amount of energy is transferred in each direction

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2
Q

When can dynamic equilibrium be reached

A

When a reversible reaction is carried out in a closed system, it will eventually reach dynamic equilibrium

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3
Q

Give two features of a reaction at equilibrium

A

The rate of forward reaction is equal to the rate of backward reaction
The concentration of reactants and products remains constant under constant conditions

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4
Q

Equilibrium can be reached from…

A

Equilibrium can be reached from both directions

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5
Q

How can you change the conditions of a reaction in a closed system

A

Change the concentration of one of the reactants
Change the temperature of he entire reaction vessel
Change the pressure inside the vessel

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6
Q

What is Le Chatelier’s principle

A

If a factor affecting the position of the equilibrium is altered, the position of the equilibrium shifts to oppose the effect of change

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7
Q

H + Cl -> HCl
Changing an equilibrium
What happens if the concentration of H is increased

A

The equilibrium shifts to the right to oppose the change by increasing the concentration of the product

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8
Q

PCl -> PCl + Cl
Changing an equilibrium
What happens if the pressure is increased

A

The equilibrium shifts to the left as there are fewer moles of gas and this opposes the change as the pressure decreases

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9
Q

What happens to equilibrium if temperature is increased

A

The equilibrium will shift to the endothermic side to oppose the chnage as it reduces temperature by absorbing heat

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10
Q

What happens to the equilibrium if temperature is decreased

A

The equilibrium shifts to the exothermic side as it opposes the change by increasing temperature as it gives out heat

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11
Q

How do Catalysts affect equilibrium

A

It increases the rate of both the forward and backward reaction equally
Equilibrium is reached faster but Catalysts do not affect the position of equilibrium

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12
Q

State the effect of a Catalyst on time taken to reach equilibrium

A

Time taken decreases

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13
Q

State the effect of a Catalyst on the position of equilibrium

A

It does not affect the position of the equilibrium

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14
Q

What are the 3 important factors to look for in equilibrium reactions in industry

A

-Yield of product
-Rate of reaction
-Cost of maintaining reaction conditions

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15
Q

Is the forward reaction in the Haber process exothermic or endothermic

A

Exothermic

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16
Q

What product does Hydration of ethene form

A

Ethanol

17
Q

Is the forward reaction in Hydration of ethene exothermic or endothermic

A

Exothermic

18
Q

What are the conditions used in the Haber process

A

450°C
200 atmospheres
Iron Catalyst
Ammonia is liquefied and removed as it is formed

19
Q

What are the conditions used in Hydration of ethene

A

300°C
60 atmospheres
Concentrated phosphoric acid Catalyst
Ethanol is liquefied and removed as it is formed

20
Q

In Hydration of ethene and the Haber process, the forward reaction is exothermic, what conditions WOULD produce the largest yield

A

Low temperature
High pressure

21
Q

What is the equation for the Haber process

A

N2 + 3H2 -> 2NH3

22
Q

Why do you compromise when low temperatures are needed

A

High yield but rate of reaction is slow

23
Q

Why compromise when high pressures are needed
Why specifically in the Hydration of ethene

A

Good yield but higher energy costs for pumps to produce the pressure and for equipment to withstand high pressures
High pressure leads to unwanted polymerisation of ethene to form poly(ethene)

24
Q

How do Catalysts help industries

A

Speed up the rate of reaction without being used up so lower temperatures can be used so lower energy costs and there is no effect on the equilibrium

25
Q

What does Kc mean

A

Equilibrium constant

26
Q

K Samsung notes

A

🕊

27
Q

What unit is used in Kc

A

Mol dm-³