Concentration of Solutions Dilution

is the process of preparing a less concentrated solution from a more concentrated one.

moles of solute before dilution = moles of solute after dilution

Dilution

is the procedure for preparing a less concentrated solution from a more concentrated solution.

Dilution Add Solvent Moles of solute before dilution (i)

M

i V i = = Moles of solute after dilution (f)

M

f V f 4.5

How would you prepare 60.0 mL of 0.2 M HNO 3 from a stock solution of 4.00 M HNO 3 ?

M

i V i =

M

f V f

M

i = 4.00

M

f = 0.200

V f = 0.06 L V i = ? L V i =

M

f V f

M

i = 0.200 x 0.06

4.00

= 0.003 L = 3 mL 3 mL of acid + 57 mL of water = 60 mL of solution

Another Dilution Problem If 32 mL stock solution of 6.5 M H 2 SO 4 is diluted to a volume of 500 mL What would be the resulting concentration?

M 1 *V 1 = M 2 *V 2 (6.5M) * (32 mL) = M 2 * (500.0 mL) M 2 = 6.5 M * 32 mL 500 mL M 2 = 0.42 M

Concentration of Solutions

Because most volumes measured in the laboratory are in milliliters rather than liters, it is worth pointing out that the equation can be written as

M

c

×

mL c mL d = M d

×