Practice question · Sort into groups
Sort each species by whether it appears in the equilibrium constant expression.
Groups: Appears in the expression · Omitted from the expression
- A pure liquid solvent such as water
- A dissolved ion taking part in the reaction
- A gas taking part in the reaction
- A pure solid reactant
Hints
- Ask whether the concentration of that species can actually vary.
- The concentration of a pure solid or liquid is fixed by its density.
Show the answer
Appears in the expression: A gas taking part in the reaction, A dissolved ion taking part in the reaction
Omitted from the expression: A pure solid reactant, A pure liquid solvent such as water
Why
Only species whose concentrations can change appear. A pure solid or liquid has a concentration fixed by its density, so it is folded into the constant rather than written out.
Practise Chemical Equilibrium
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