IBDP Equilibirum SL 2016

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Equilibrium J Midgley Head of Chemistry Guernsey Grammar and Sixth Form Centre 2015 these slides are in no way endorsed by the ………………………………..

Transcript of IBDP Equilibirum SL 2016

Equilibrium

J MidgleyHead of ChemistryGuernsey Grammar and Sixth Form Centre2015

these slides are in no way endorsed by the ………………………………..

Essential UnderstandingsMany reactions are reversible. These reactions will reach a state of equilibrium when the rates of the forward and reverse reaction are equal. The position of equilibrium can be controlled by changing the conditions.

A state of equilibrium is reached in a closed system when the rates of the forward and reverse reactions are equal.

Criteria for establishing equilibirum

1. Rate of forward = rate of backward reaction2. Closed system…..3. Equilibrium is the state of equal,

opposite rates, not equal concentrations.

7.1 Kc from the chemical equation

1. In LHS finish the expression for Kc.

2. Write the rules for working out Kc.

3. Write out the original reaction from the Kc expression above.

Problems - write Kc expression for...(The IB will only ask for homogeneous equilibria - catalyst need not be in same phase)

1. CH3COOH(l)+CH3CH2OH(l)⇌CH3COOCH2CH3(l)+H2O

2. 2SO2(g)+O2(g)⇌2SO3(g)

3. N2(g)+3N2(g)⇌2NH3(g)

7.2 Magnitude of Kc

The Haber Process ……Review effects of changing T,P on position of equilibirum and hence value of Kc.

Kc and Q

When Kc = Q we have equilibirum.

If Q > Kc then equilibirum shifts to _____.

If Q < Kc then equilibirum shifts to _____.

Q vs Kc

Le Chatelier’s Principle

Animation here.

Homework

Create a thoughtful colourful infosplurge contrasting the Haber process and the Contact process.