13 CH Solutions!
Solution = stable homogeneous mixture;
has the same composition throughout,
does not settle out, and particles are
dissolved; cant distinguish phases under
a microscope
The solute is what gets dissolved and the
solvent is what does the dissolving.
In salt water the salt is the solute and
water is the solvent.
Not all solutions are liquids only:
1. Solid in a liquid = salt water
2. Gas in a liquid = soda pop (carbon
dioxide in water) or in a lake dissolved
oxygen in water.
3. Gas in Gas = Air around us is mixture of
mainly nitrogen and oxygen
4. Liquid in liquid = alcohol in water
5. Solid in a solid = these are also known as
alloys.
Ex. Liquid in liquid mixture
5 ounces of wine
24 proof
24 2 = 12
(% alcohol)
12 100 = 0.12
0.12 x 5 oz
=
0.6 ounces
ethanol
12 ounces of
beer
10 proof
10 2 = 5
(% alcohol)
5 100 = 0.05
0.05 x 12 oz
=
0.6 ounces
ethanol
1 1/2 shot
80 proof
8 0 2 = 40
(% alcohol)
40 100 = 0.4
0.4 x 1.5 oz
=
0.6 ounces
ethanol
FYI
Other types of alcohol are not safe to drink.
They can be toxic and even fatal is
consumed. They include:
Butyl alcohol, or butanol. This type of
alcohol, derived from butane, is commonly
used in products such as adhesives and
varnishes.
FYI
Methyl alcohol, also known as methanol or
wood alcohol. It is used in the manufacture
of formaldehyde and as industrial solvent.
During Prohibition wood alcohol gained
notoriety as a mixing agent with ethyl
alcohol to make liquor.
Several people became blind after
drinking this toxic mixture, as methyl
alcohol causes swelling of the optic nerve,
an irreversible condition.
FYI
Isopropyl alcohol, also known as rubbing
alcohol, is a common household product.
It is used as a disinfectant and as an
ingredient in cologne and after-shave
lotion.
Ethylene glycol, also known as antifreeze,
is the most harmful type of alcohol. It
should never be consumed, as it is deadly.
Examples of Alloys:
Brass copper + zinc
Bronze copper + tin/aluminum
Steel iron, carbon + others
White gold gold + Ni + Pd
Wrought iron iron + carbon
13.2 Concentration & Molarity
In a solution, the solute is distributed
evenly throughout the solvent.
Any part of the solution has the same
solute to solvent ratio or concentration
Concentrations can be expressed in many
forms Ex. molarity, ppm, molality
Name
Abbreviatio Units
n or symbol
Areas of
Application
Molarity
M
mol solute
L solution
Solution
stoichiometry
Molality
m
mol solute
kg solvent
calc. of
colligative
properties
Parts
per
million
ppm
g solute
1000 000 g
solution
To express
small
concentrations
Parts per million (ppm) =
gram solute per one million grams
solvent; used in measurements such as
pollution that involve very low
concentrations
1 mg/L = 1 ppm
Ex. Lead in drinking water
ppm = gram solute
1 000 000 g solution
Parts are measured by mass
Sample Problem A p. 461
A chemical analysis shows that there are 2.2 mg of lead in exactly 500 g of a
water sample (solution). Convert to ppm. (grams solute/one million grams
solution)
Convert mg to grams
1 gram
2.2 mg x1000 mg
=
2.2 x 10-3 g of Pb
Divide by 500 grams to get the grams (parts) in 1 gram
of water. Multiply by 1 000 000 to get the amount of
grams in 1 000 000 g water.
2.2 x 10-3 g of Pb x 1 000 000 parts = 4.4 ppm Pb in the
water
500 g H2O
1 million
4.4 grams of lead for every 1 000 000 grams of
Practice Problems #1-7 p. 461
1. Helium gas, 3.0 x 10-4g, is dissolved in
200.0g of water. Express in ppm.
3.0 x 10-4g He x 1 000 000 parts
1 million
200.0 g H20
= 1.5 ppm
Practice Problems #1-7 p. 461
2. A sample of 300.0g of drinking water is
found to contain 38 mg Pb. Express in
ppm.
38 mg Pb x 1 g
= 0.038 g
1000 mg
0.038 g Pb
300.0 g H20
x 1 000 000 parts
1 million
= 126.6
= 130 ppm
Practice Problems #1-7 p. 461
3. A solution of lead sulfate contains 0.425
grams of lead sulfate in 100.0 grams of
water. Express in ppm.
0.425 gPbSO4 x 1 000 000 parts
1 million
100.0 g H20
= 4250 ppm
Practice Problems #1-7 p. 461
4. A 900.0 g sample of sea water is found to
contain 6.7 x 10-3 g Zn. Express in ppm.
6.7 x 10-3 g Zn. x 1 000 000 parts
900.0 g H20
1 million
= 7.4 ppm
Practice Problems #1-7 p. 461
5. A 365.0 gram sample of water contains
23 mg Au. Express in ppm.
23 mg Au x
0.023 g Au
365.0 g H20
1g
= 0.023 g
1000 mg
x 1 000 000 parts
1 million
= 63 ppm
Practice Problems #1-7 p. 461
6. A 650.0 g hard-water sample contains
101 mg Ca. Express in ppm.
101 mg Ca x
0.101 g Ca
650.0 g H20
1 g = 0.101 g
1000 mg
x 1 000 000 parts
1 million
= 155 ppm
Practice Problems #1-7 p. 461
7. An 870.0 g river water sample contains
2.0 mg Cd. Express in ppm.
2.0 mg Cd x
1g
= 0.0020 g
1000 mg
0.0020 g Cd
870.0 g H20
x 1 000 000 parts
1 million
= 2.3 ppm
Which of the following would be the most
concentrated solution? (Hint: density of water
1g/1mL)
A.200 g of C12H22O11 in 1 kg of water
B.1000 ppm of C12H22O11 in water
C.1500 ppm of C12H22O11 in water
A. 00 grams C H O x 000 0000 = of 000 ppm
D.1 2mol of C12H22O111 in 1 L 200 solution
12
22
1000 grams water
11
1 million
D. 1 mol = 12(12) + 22(1) + 11(16) = 342 g SO
1 L x 1000 mL x 1 g = 1000 g
1L
1 mL
342 grams C12H22O11 x 1000 0000 = 342 000 ppm
1000 grams water
1 million
Application:
p. 489 # 37-40
Molarity
Allows chemists to describe the number
of solute particles in a volume of total
solution (not just solvent)
Molarity = moles of solute dissolved in a
liter of solution
M = mol/L
(read moles per liter or molar)
[ ] = molarity (in aqueous solution)
[CuSO4] = 0.5 M
The molarity of copper sulfate
is 0.5 M or moles per liter.
[NaNO3] = 1.0 M
The molarity of sodium nitrate is
1.0M. Also called a 1 molar
solution.
Sample B p.465
Calculating Molarity
Molarity = moles of solute
liters of solution
What is the molarity of a potassium
chloride solution that has a volume of
400.0 mL and contains 85.0g KCl?
Step 1 Convert solute to moles.
85.0 g KCl x
1 mol
= 1.14 mol KCl
74.55 g KCl
Step 2 Convert solution to liters.
400.0 mL x 1L
= 0.400 L
1000 mL
Step 3
Divide moles by liters. 1.14 mol KCl = 2.85 M
KCl
0.400 L
Practice p. 465 #1-7
Calculate molarity of the given
solutions.
1. Vinegar contains 5.0g of acetic acid,
CH3COOH, in 100.0 mL of solution.
5.0 g x 1 mol = 0.083 mol acetic acid
60 g
0.083 mol = 0.83 M acetic acid solution
0.100 L
2. If 18.25g HCl is dissolved in enough water
to make 500.0mL of solution, what is the
molarity of the solution?
18.25 g x 1 mol = 0.5005 mol HCl
36.46g
0.5005 mol = 1.001 M hydrochloric acid
solution
0.500 L
3. If 20.0 g H2SO4 is dissolved in enough
water to make 250.0mL of solution, what is
the molarity of the solution?
20.0 g x 1 mol = 0.204 mol
98.09g
0.204 mol = 0.816 M sulfuric acid solution
0.2500 L
4. A solution of AgNO3 contains 29.66 g of
solute in 100.0 mL of solution. What is the
molarity of the solution?
29.66 g x 1 mol = 0.175 mol
169.9g
0.175 mol = 1.75 M silver nitrate solution
0.1000 L
5. A solution of barium hydroxide, Ba(OH)2,
contains 4.285 g of solute in 100.0 mL of
solution. What is molarity the of the
solution?
4.285 g x 1 mol = 0.0250 mol
171.35g
0.0250 mol = 0.2501 M barium hydroxide
solution
0.1000 L
6. What mass of KBr is present in 25 mL of a
0.85 M solution of potassium bromide?
x mol = 0.85M x = 0.85 mol X 0.025 L = 0.021
mol
0.025L
L
0.021 mol KBr x 119 g = 2.5 g KBr
1 mol
7. If all of the water in 430.0 mL of 0.45 M NaCl
solution evaporates, what mass of NaCl will
remain?
x mol = 0.45M x = 0.45 mol X 0.4300 L = 0.19
mol
0.4300 L
L
0.19 mol NaCl x 58.44 g = 11 g NaCl
1 mol
Application:
p. 489 # 41-45
9.2 Review p. 467
# 2,4-9
Preparing a Solution of Specified
Molarity
If you add 1.000 mol solute to 1.000 L of
solution, the molarity would NOT be
1.000M.
Why not???
The added solute would change the total
volume of the solution.
Molarity would be = 1 mol = 0.83M
1.2 L
Preparing 1.000L of solution (p. 463)
1. Convert moles to mass using molar
mass.
2. Measure amount needed in grams.
3. Add small amount water (solvent) to
beaker and dissolve.
4. Pour into 1.000 L volumetric flask.
5. Rinse beaker and pour into flask.
6. Stopper flask & swirl.
7. Carefully add water to 1.000L mark on
flask.
Why dont you
fill with water to
the 1000 mL
mark and then
add solute?
Because then
the total
volume of the
solution will
be greater
Video
Application: Molarity Lab
Dilution = adding more solvent to a
solution so that the concentration of
the solute becomes lower.
The total number of solute particles in the
solution remains the same after dilution, but the
volume of the solution becomes greater, resulting
in a lower molarity, ppm, mg/L, or %
concentration.
Dilution video
Dilution Preparation of Solutions
END OF PART 1 NOTES
13.3 Solubility & Dissolving
Solubility =
ability of one substance to dissolve into
another at a given temperature &
pressure.
Dissolving Liquids
Miscible = 2 liquids that are able
to dissolve into each
other
Immiscible = do not mix; form 2
layers upon settling,
droplets when mixed
These liquids are
immiscible. Nonpolar
molecules form droplets
Two mutually immiscible
liquids in a cylinder are
heated with a light bulb.
The density of the liquids
change as they are
heated and cooled.
DISSOLVING SOLIDS
Solvation (aka dissolution) =
process of breaking apart the crystal
lattice of ionic solids
Hydration = as ions dissolve in a solvent
they spread out and become surrounded
by solvent molecules.
Water molecular are polar
Partially positive hydrogen surrounds neg.
ions
Partially negative oxygen surrounds pos. ions
Solubility depends on
1.Nature of solute & solvent molecules
2.Surface area
3.Temperature
4.Pressure (for gases only)
1. Nature of Solute/Solvent POLARITY
Like dissolves like
A polar covalent solvent will dissolve ionic
solutes and other polar covalent solutes
A nonpolar covalent solvent will dissolve
nonpolar solutes
Video
Why no discussion
of ionic solvents?
Water is a common example of a polar
solvent.
Carbon tetrachloride is a common
example of a nonpolar solvent unequal
sharing geometrically cancels/balances
immiscibl
e
Iodine Crystals
nonpolar
The purple iodine crystal remains
undissolved (insoluble) in the water
Iodine has dissolved (soluble) in the
CCl4
Iodine molecules are nonpolar (identical
atoms share equally).
WATER
CCl4
Sugar
WATER
CCl4
You can see that the sugar has
dissolved in the water but has not
dissolved in the carbon tetrachloride
Sugar molecules contain polar
angular C-O-H groups.
Ethanol
Miscible with both.
Half of each ethanol
molecule contains a
polar C-O-H group
and the other half
contains essentially
nonpolar C-H
bonds.
That gives ethanol
molecules both polar
and nonpolar
WATER
CCl4
There are many degrees of polarity, all
sorts of gradations in between the
extremes of polar and nonpolar.
WATER
ACETO
NE
ETHANO
L
CCl4
Ex. The solubility of nonpolar iodine
increases as the polarity of the solvent
decreases.
2. Surface Area
Greater the surface exposed to
the solvent, the faster dissolving
occurs
Coarse salt vs. table salt smaller
pieces
Mixing/shaking increases contact
What does a sugar cube have to
do with this concept?
Same mass of granules
dissolve faster than cube
3. Temperature
For most solids, solubility increases as
temperature increases
As temperature increases, solvent
particles move faster and collide more
often with surface of solute
From left to right temperature increases, does the curve of
solubility increase, stay the same, or decrease?
1. NaNO3 &
many
others
2. NaCl
3. Ce2(SO4)
3
For most gases,
solubility decreases
as temperature
increases
A short metal rod is
heated and then
dropped into a freshly
opened bottle of root
beer.
A fountain of foam
shoots out since
carbon dioxide is less
soluble in warm root
Saturation
= a solution that cannot dissolve any more
solute under the given conditions
As long as a solution is unsaturated, more
solute can be added and dissolved
What evidence can you see that might
indicate that this solution is saturated?
Supersaturated Solutions
= solution holding more than normal
dissolved solute at a given temperature.
Heat to dissolve, then allow to cool
Cooled add seed crystal and excess
solute comes out of solution.
Video: Sodium Acetate
Example: hot packs (same chemical)
Homework: Worksheet 13.3
19.4 Physical Properties of
Solutions
1. Conduct electricity if contain charged
particles (ions)
Nonelectrolytes do not increase the electrical
conductivity of water
Electrolytes do increase the electrical
conductivity of water
Weak electrolytes cause a mild increase
Strong electrolytes cause a greater increase
Electrical Conductivity of Solutions
Electrocuting a Pickle
Non-electrolytes
Strong electrolyte
Weak electrolyte
Dissolution of an Ionic and a Covalent Compoun
Does tap water conduct electricity?
Does pure water conduct electrity?
Water only conducts electricity if it
contains dissolved electrolytes.
Is bottled water pure water?
Is distilled water pure water?
2. Colligative Properties
The next time you see a container of
antifreeze, look on the label and it will
show you that as you increase the amount
(concentration, actually) of the antifreeze
in the car's cooling system the freezing
point of the solution decreases. There is a
limit to that, and the instructions usually
say that you should not exceed a certain
percentage. If you get to the point where
you have water in the antifreeze rather
The effect on the boiling point is just the
opposite; that is, the boiling point of a
liquid is increased if something is
dissolved in it.
Again, the antifreeze in a car radiator is an
example of this. In the advertisements it's
called summer protection against boilovers. Essentially what they have done is
raised the boiling point of the liquid, of the
water, by making it a solution.
Emulisifier
Kerosene and water are shaken together and separate rapidly.
Adding liquid soap to the mixture produces a temporary emulsion
when the flask is shaken again. The emulsion separates slowly.