3-Equilibria Flashcards Preview

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Flashcards in 3-Equilibria Deck (20)
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1
Q

What is a static equilibrium?

A

All the processes which might disturb the reaction have stopped

2
Q

What is a dynamic equilibrium?

A

The forward and reverse reactions are occurring at the same rate, represented using the double arrow

3
Q

What is Kc for the reaction:

aA + bB –> cC + dD

A

[C]^c [D]^d / [A]^a [B]^b

4
Q

What is Kc?

A

Equilibrium constant

5
Q

How would you work out Kc for the backward reaction from the other Kc value?

A

1/ Kc

6
Q

What does an equilibrium constant in terms of concentration apply to?

A

When all the reactants and products are in the same phase, a homogenous equilibria

7
Q

What is partial pressure?

A

The pressure that the gas would have if it occupied the volume alone

8
Q

How can partial pressure be worked out?

A

Pa = (no. mol of a/total mol) x total pressure

9
Q

What is Kp for the reaction:

aA + bB –> cC + dD

A

p(C)^c x p(D)^d

p(A0^a x p(B)^b

10
Q

What is a heterogenous equilibria called?

A

An equilibria which exists in more than one phase

11
Q

Why are solids not included in K?

A

‘Concentrations’ of solids are constant so are removed

12
Q

What does a very large value of K (K>1x10^10) show about the extent of reaction?

A

Reaction proceeds almost to completion, leaving very small amounts of reactants at equilibrium
Position of equilibrium lies to the right

13
Q

What do a very small value of K (K

A

Reaction hardly occurs, producing very small quantities of products at equilibrium
Position of equilibrium lies to the left

14
Q

What do values around 1 of K show?

A

Concentrations of reactions and products are almost the same at equilibrium

15
Q

How do you determine an equilibrium constant?

A

Combine known quantities under controlled conditions and allow them to go to equilibrium
Accurately measure the conc in the mixture to allow to you to calculate the other concs
Substitute into equilibrium expression and calculate

16
Q

How can you calculate the equilibrium constant for the distribution of iodine in two immiscible liquids? What is it called?

A

partition constant

Kpart= conc iodine in hexane/ conc in water

17
Q

What is ΔStotal in reversible reactions?

A

Forward and backward reaction must be spontaneous so it is positive
0

18
Q

What does ΔStotal between 40 and -40 tell you about the extent of reaction?

A

Mixture of reactants and products

19
Q

What does ΔStotal >+200 tell you about the extent of reaction?

A

Reaction is complete

20
Q

What does ΔStotal >-200 tell you about the extent of reaction?

A

Reaction does not take place