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Classification of Matter
Matter
Pure
Substances
Elements
Compounds
Mixtures
Homogeneous
Mixtures
Heterogeneous
Mixtures
Mixtures
homogeneous:
• will not separate
heterogeneous:
• settles upon standing
• small particles
• variable particle sizes
– evenly distributed
– too small to be seen
– can’t be sorted or trapped by
filter
– won’t scatter light
– uneven distribution
– visibly different regions
– can be separated depending
on particle sizes
– scatters light
Solution
homogeneous mixture of 2 or
more substances in a single
physical state (phase)
Parts of a Solution
• solute = substance being
dissolved
• solvent = dispersing medium
substance being dissolved into
Can you identify the
solute and solvent in
each picture?
solute = ?
solvent = ?
hints to identify solute & solvent
• solute:
–substance that changes phase
–substance that have less of
• solvent:
–substance that maintains phase
–substance that have more of
Aqueous Solutions
• water is
solvent
• transition
metals form
brightly
colored
solutions
solutions occur in all 3 phases
solute
solvent
example
gas
gas
air
liquid
gas
water vapor in air
solid
gas
SO2(s) in air - smog
gas
liquid
CO2(g) in water (soda)
liquid
liquid
antifreeze(l) in water in car radiator
solid
liquid
salt water
gas
solid
H2(g) in palladium metal
liquid
solid
dental amalagum fillings: Hg (l) in Au(s)/Ag(s)
solid
solid
alloys: Brass, etc.
gas in a liquid:
CO2 in and out of water
bubbles mean it’s a mixture not a solution!
Concentration
of
Solutions
Concentration
• measurement that describes
how much solute in given amount of
solvent or solution
• express concentration using many,
many different units
– pick the unit according to task at hand
Percent
• by mass
OR
• by volume
% =
part x
whole
100
Twists in Word Problems
• sometimes ask for part or whole, not percent
• sometimes give volume/mass of solution
• sometimes give volume/mass of solvent and
volume/mass of solute
mass solution = mass solute + mass solvent
ppm (parts per million)
• used when solute is present in very small
amounts
(Regents board doesn’t quite follow this rule)
ppm (parts per million)
ppm =
grams solute x
grams solution
1,000,000
• ppm is ratio between mass solute & mass soln
• similar to % except the whole is 1,000,000
instead of 100
About 0.0043 g of O2 can be
dissolved in 100 mL of water at
20oC. Express in ppm.
[memorize: 1 mL water has mass of 1 g]
• ppm = 0.0043g x
100.0043g
= 43 ppm
1,000,000
CO2 gas has solubility of
0.0972 g/100 g water at 40oC.
Express in parts per million.
ppm =
0.0972 g solute
x
100.0972 g solution
= 971 ppm
1,000,000
What is the concentration in ppm of a
solution with 30.0 g NaNO3 in
70.0 g water?
ppm =
30.0 g NaNO3
100.0 g solution
x
1,000,000
= 300,000 = 3.0 X 105 ppm
How many grams of KOH are
needed to be dissolved in water to
make 2000.0 grams of a 10.0 ppm
solution?
10 ppm =
? grams KOH
X 1,000,000
2000.0 g solution
? = 0.02 grams KOH