Ion Concentration

Dissociation

- Ionic compounds are made up of two parts

- Cation: positively charged particle

- Anion- Negatively charged particle

- When ionic compounds are dissolved in water the cation and anion separate fro m each other

- This process is called dissociation (splitting apart the ions)

When writing dissociation equation, the atoms and charges must balance

The Dissociation of Sodium Chloride is:

NaCl ----> Na (+1) +  Cl (-1)

Complete the following dissociation equation:

Fe(OH)2  ---->   Fe (+2) + OH (-1)

Balanced ----->  Fe (+2) + 2OH (-1)

If the volume does not change then the concentration of individual ion depends on the balanced

coefficients in the dissociation equation.

Determine the [NA(+1)] and [PO4 (-3)] in a 1.5 M solution of Na3PO4:

Na3PO4 ---> 3Na (+1) + PO4 (-3)

1.5 M        (1.5x3) 4.5 M       1.5 M

If the [Cl (-1)] = 0.752 M in a solution of ZnCl2 determine the solution's concentration:

ZnCl2 -----> Zn (+2) + 2Cl (-1)

-0.752M = 0.376 M

-If two solutions are added together the volume changes.

-The ions are diluted (C1V1 = C2V2)

http://www.youtube.com/watch?v=EBfGcTAJF4o
Dissociation of Salt

Jomar Delos Santos