Ion Concentration

DISSOCIATION

• ionic compounds are made up of two parts
• Cation: positively charged particles
• Anion: negatively charged particles
• when ionic compounds are dissolved in water, the cation and anion separate from each other
• this process is called dissociation
• when writing dissociation equation, the atoms and charges must balance.
• the dissociation of sodium chloride is:

NaCl -> Na+ + Cl-

• if the volume does not change then the concentration of individual ions depends on the ba;anced coefficient in the dissociation

ex. Determine the [Na+] and [PO4 3-] in a 1.5 M solution of Na3PO4

Na3PO4 -> 3Na+ + PO4 3-

1.5 M = [PO4 3-]

1.5 x 3 = 4.5 M = [Na+]