Chemistry - Aqueous

pH + pOH =

14

Relationship between Ka, Kb, and Kw

KW= Kb x Ka

Solubility product

Ks

MolL^-1 into gL^-1

multiply by molar mass (M)

gL^-1 into MolL^-1

divide by molar mass (M)

Precipitation will not occur if?

Q<Ks

Precipitation will occur if?

Q>Ks

Precipitation will continue until?

the ions concentrations decrease to the equilibrium levels

Common ion effect

solubility of one salt is reduced by the presence of another having a common ion

define Ks

equilibrium constant describing the solubility of compounds that are sparingly soluble in water

Define saturated solution

a solution that contains as much dissolved solute as it can under a given set of conditions

Define buffer solution

solution whose pH resists change upon addition of small amounts of H^+ and OH^-

When are buffer solutions most effective

when the concentrations of acid and base are equal

Define equivalence point

the pH when equivalent amounts of acid and base have been mixed

How to choose an indicator

working range of the indicator is approximately equal to pKa of indicator + pH unit

Define buffer region

region where acid/base conjugate pair are approximately equal concentrations

If a buffer is diluted…

its pH is unchanged but its ability to act as a buffer decreases as lower conc of acid and base

Salt hydrolysis

when salts dissolve in water, the solution is not always neutral due to the reversible reaction between the salt ions and the water

The equivalence point is reached when?

the moles of acid and base are equal

conductivity of strong acids/bases

goods conductors as their ionization with water is complete

conductivity of salts

strong conductors due to full dissociation in water

pH depends on?

the extent of the reaction with water

A substance’s solubility is expressed as either:

•  solubility (s) in g L^-1

• molar solubility in mol L^-1