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AQA A Level Chemistry復習筆記5.3.1 Kp Expressions

Category: A-level課程, 教材筆記, 福利干貨 Date: 2022年6月27日下午3:19

We have seen previously that equilibrium reactions can be quantified by reference to an equilibrium expression and equilibrium constant
The?equilibrium expression?links the?equilibrium constant,?Kc, to the?concentrations of reactants and products?at equilibrium taking the?stoichiometry?of the equation into account
So, for a given reaction:

aA + bB ? cC + dD

Kc?is defined as follows:

1.7-Equilibria-Equilibrium-Expression

Equilibrium expression linking the equilibrium concentration of reactants and products at equilibrium

Solids?are ignored in equilibrium expressions
The?Kc?of a reaction is constant and only changes if the?temperature?of the reaction changes

This section covers how we manage gases in calculating the equilibrium constant and how an equilibrium yield is affected by the partial pressures of reactants and products
Many industrial process involve reactions between gases so this application has important consequences for controlling reaction conditions
In the generic example above, if all the substances are gases, we can show the equation with that state symbol

aA (g) + bB (g) ? cC (g) + dD (g)

We can write a different equilibrium expression in terms of the?partial pressure?of the gases
This equilibrium constant is called?Kp?and is defined as follows

5.3.1-Kp-Expressions

Equilibrium expression linking the partial pressures of reactants and products at equilibrium

Solids?and?liquids?are ignored in?Kp?equilibrium expressions
The?Kp?of a reaction is constant and only changes if the?temperature?of the reaction changes