Page 32 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

Writing equilibrium constant expressions

• For a reversible balanced reaction:

aA + bB ⇌ cC + dD

• the equilibrium constant K is defined as:
eq

[ ] [ ]
=

[ ] [ ]

• Note: The concentrations of solids and pure liquids are not included in the

equilibrium expression because their concentrations are assumed to be constant during
reactions.

Quiz

What is the equilibrium constant expression K , for the following balanced
eq
equation?
2+ −
PbCl (s)⇌Pb (aq)+2Cl (aq)
2

What is the equilibrium constant expression K , for the following balanced
eq
equation?
P (g) + 5O (g) ⇌ P O (s)
4 2 4 10

What is the equilibrium constant expression K , for the following balanced
eq
equation?
+ 2+
Cu(s) + 2Ag (aq) ⇌ Cu (aq) + 2 Ag(s)

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