Solutions

Concentration of Solutions

Concentration = # of fish

volume (L)Concentration =

V = 1000 mL

n = 2 fish

Concentration = 2 “fishar”

V = 1000 mL

n = 4 fish

[ ] = 4 “fishar”

V = 5000 mL

n = 20 fish

[ ] = 4 “fishar”

1 fish

1 (L)

Concentration = 1 “fishar”

V = 1000 mL

n = 2 moles

Concentration = 2 molar

V = 1000 mL

n = 4 moles

[ ] = 4 molar

V = 5000 mL

n = 20 moles

[ ] = 4 molar

Concentration = # of moles

volume (L)V = 250 mL

n = 8 moles[ ] = 32 molar

Concentration…a measure of solute-to-solvent ratio

concentrated vs. dilute “lots of solute” “not much solute”

“watery”

Add water to dilute a solution; boil water off to concentrate it.

Making a Dilute

SolutionTimberlake, Chemistry 7th Edition, page 344

initial solution

removesample

diluted solution

same number ofmoles of solutein a larger volume

mix

moles ofsolute

Concentration“The amount of solute in a solution”

mol

L M

A. mass % = mass of solute mass of sol’n

B. parts per million (ppm) also, ppb and ppt – commonly used for minerals or contaminants in water supplies

C. molarity (M) = moles of solute L of sol’n

– used most often in this class

D. molality (m) = moles of solutekg of solvent

M = mol L

% by mass – medicated creams% by volume – rubbing alcohol