A2 OCR Salters B Chemistry 7.2 Equilibria and concentrations

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Created by: Emily
Created on: 08-01-13 18:19

What do square brackets [ ] represent?

Concentration in mol dm-3

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In equilibria reactions, What does p represent?

The pressure of a gas in atmosphere (atm)

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What is the equation for the equilibrium constant, Kc, for reaction aA + bB ↔ cC + dD?

([C]^c x [D]^d) divided by ([A]^a x [B]^b)

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What is the equilibrium constant Kc affected by?

The temperature only

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What is the unit of the equilibrium constant Kc?

It depends on the particular equilibrium expression. Use the equation for the equilibrium constant except use mol dm-3 with mole ratios as the indices.

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Based on Le Chatelier’s principle of reactions in equilibrium, what will happen to a reaction if some extra amount of a reactant/product was added?

The equilibrium of the reaction would shift to oppose the change and remove the extra chemical

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For the reaction H2 + Br2 ↔ 2HBr, describe how the equilibrium changes when the following happens: more Br2 is added, OH- is added or more HBr is added.

1 - Equilibrium shifts to right, 2 - O reacts to form water meaning loss of HBr so equilibrium shifts to right to counter this, 3 - Equilibrium shifts to left

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What is the effect of using a catalyst on the equilibrium of a reaction and the equilibrium constant Kc?

This only changes the rate. It doesn’t affect the position of eq or the Kc

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What is the effect of changing the pressure on the equilibrium of a reaction and the equilibrium constant Kc?

Increasing press moves eq to side with fewer gas molecules to reduce press and vice versa. Kc is unaltered

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What is the effect of changing the temperature on the equilibrium of a reaction and the equilibrium constant Kc?

Equilibrium shifts to side where endothermic reaction is taking place. Kc dos change

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Other cards in this set

Card 2

Front

In equilibria reactions, What does p represent?

Back

The pressure of a gas in atmosphere (atm)

Card 3

Front

What is the equation for the equilibrium constant, Kc, for reaction aA + bB ↔ cC + dD?

Back

Card 4

Front

What is the equilibrium constant Kc affected by?

Back

Card 5

Front

What is the unit of the equilibrium constant Kc?

Back

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A2 OCR Salters B Chemistry 7.2 Equilibria and concentrations