Name: ___________________________________
CHAPTERS 15 and 16: Water and Solutions
Period:___________________
PART I Solutions - https://youtu.be/TNxHEgLO6ig
1. DETERMINING THE RIGHT SOLUTE/ SOLVENT COMBINATION: REVIEW “Like dissolves Like”
If the SOLUTE is:
The SOLVENT is:
Ionic (+/-) dissolves in 
water
Polar covalent: dipole forces (stronger)
Ex: CH2O, PH3 dissolves in 
Water, other polar covalent (alcohol)
NEW: extremely polar molecules (Hydrogen Bonding)
Ex: NH3, HF, H2O dissolves in 
Nonpolar covalent: (weak London dispersion forces)
Ex: CH4, fats, I2 dissolves in 
Nonpolar covalent (hexane,CCl4)
a. STOP and THINK Which substances below would you predict to be soluble in water? In alcohol? First
identify if the solute is I (ionic) , M (metallic). PC (polar covalent) or NPC (non-polar covalent)
https://youtu.be/gxmpr09Xk4Y
Soluble in Water? (a
Soluble in Alcohol?
Soluble in Nonpolar Solvents?
VERY Polar Solvent)
(Polar – dipole; but not as polar as
water)
(ex. CCl4)
K2SO4
C5H12
Cu
C2H5OH
b. How and why do solutes dissolve in water? https://youtu.be/OPLU_tKFIEU
Solution Formation is a 3 step process
Step 1: Solvent particles must separate from other solvent particles .
Solvent particles are attracted to other solvent particles by
Intermolecular forces which must be broken
Step 2: Solute particles must separate from other solute particles .
For example: since the ions of solutes like NaCl are in a crystal
lattice structure, the electrostatic attractions between them must be broken .
Step3: Solvation has occurred when solvent particles surround and
interact with solute particles.
c. Do all ionic solids dissolve in water?__ NO – many do not. If the ions are more attracted to each other than to
water, they are insoluble (e.g. carbonates, sulfates)
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2. Intermolecular Forces - https://youtu.be/BqQJPCdmIp8 (liquid lesson)


Weak forces between covalent molecules.
Dispersion, Dipole Forces, and Hydrogen bonds
Hydrogen Bonds : These are the strongest Intermolecular Forces. Look for molecules that contain “H”
bonded to N, O, or F.
STOP and THINK: Looking at the diagrams above
Is there a hydrogen bond between one H2O and another H2O?______
Are there a hydrogen bonds within a water molecule?______
Are hydrogen bonds found in a molecule of H2?______
Is there a hydrogen bond between two H2 molecules ?_____
3. Properties of Water due to Hydrogen Bonding:
PROPERTY
1) Heats up/cools down
slowly:
2
EFFECT
Pool water “colder” than outside temp. during summer (especially in
the morning). Lake water warmer at night.
2) Requires a lot of energy to
melt/vaporize:
Low molar mass usually means low boiling point at normal atm
pressure. Comparing H2O and NH3 (18g/mol and 17g/mol). H bonds
between H2O are very strong.
3) Solid is less dense than
liquid until 4°C (DENSITY)
Ice floats on water
4) Surface Tension
More dense substances can float on water (insects can walk on
water), forms droplets
4. SOLUBILITY - https://youtu.be/hut2Qujue_c
Effects of
Temperature
and
Pressure
1. Temperature affects the solubility of solids, liquids and gases.
If the temperature is increased, then the solubility of liquids and solids( increases / decreases )
If the temperature is increased, then the solubility of gases( increases / decreases )
2. Changes in pressure only affect the solubility of ( solids / liquids / gases )
An increase in pressure will ( increase / decrease ) the solubility
of a gas.
2. List 3 factors that affect the RATE of solubility (the speed that you can dissolve a substance).
a.________________________________________________
b.________________________________________________
c.________________________________________________
3
5. UNDERSTANDING and READING SOLUBILITY CURVES - https://youtu.be/AG6wcmrYRro
On the line: Saturated solution
 Solvent holds as much solute as
possible at that temperature.
Below the line: Unsaturated Solution
 Less than the maximum
amount of solute for that
temperature is dissolved in the
solvent.
 No solid remains in flask.
Above the line: (not heated)
 Undissolved solid (precipitate)
remains in flask.
 *Supersatured: (heated then
slowly cooled)
 Appears clear, no
precipitate
Reading Solubility Curves:
a. What is the solubility of potassium nitrate at
50°C?
b. What mass of potassium nitrate could dissolve in 250g of water at 50ºC?
c. What mass of potassium nitrate could dissolve in 250g of water at 10ºC?
d. What happens to the solubility of potassium nitrate as the temperature decreases?
4
e. Is this true for every salt?
f. Ammonia (NH3) is a gas. What happens to its solubility as the temperature increases?
g. Which substances solubility seems to be least affected by temperature?
5
READING SOLUBILITY CURVE:Saturated, unsaturated, and super saturated
The solubility curve below is just for sugar and sodium chloride.
a. Find the solubility of sugar at 20°C. _______________________
b. If I add 125.0g of sugar to 100g water at 20°C and stir, the solution will be ____________________.
The solution will appear:
c. If I add 200g of sugar to 100g of water at 20°C and stir, the solution will be____________________.
The solution will appear:
c. If I add 250g of sugar to 100g of water at 20°C and stir, the solution will be____________________.
The solution will appear:
The solution will NOT be supersaturated because: _________________________________________
________________________________________________________________________________________
d. The solubility of sugar in 100g of water at 90°C is ________________. 400g of KCl are added to 100g of
water at 90°C. The solution is then slowly cooled to 20°C. Two things could happen:
1. If solid sugar begins to precipitate, the solution is ______________________.
A total of _________ g of sugar will precipitate.
2.
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If no solid appears, the solution is ________________________________.
6. UNITS OF CONCENTRATION - https://youtu.be/ZXnRMVhRptk
a. Molality
Molality(m) =
𝒎𝒐𝒍𝒆𝒔 𝒔𝒐𝒍𝒖𝒕𝒆
𝒌𝒈 𝒔𝒐𝒍𝒗𝒆𝒏𝒕
1.
Determine the molality of a solution prepared by dissolving 20.0g of CaCl2 in 500g of water.
2.
A student dissolves 42.0g of KNO3 in 650g of water. Determine the molality of the resulting solution.
3.
How many moles of sugar must be dissolved in 450g of ethanol in order to prepare a 0.75m solution?
b. % Solution
% Solution =
𝐦𝐚𝐬𝐬 𝐬𝐨𝐥𝐮𝐭𝐞
𝐭𝐨𝐭𝐚𝐥 𝐦𝐚𝐬𝐬 𝐨𝐟 𝐬𝐨𝐥𝐮𝐭𝐢𝐨𝐧
-OR-
𝐯𝐨𝐥𝐮𝐦𝐞 𝐬𝐨𝐥𝐮𝐭𝐞
𝐭𝐨𝐭𝐚𝐥 𝐯𝐨𝐥𝐮𝐦𝐞 𝐨𝐟 𝐬𝐨𝐥𝐮𝐭𝐢𝐨𝐧
Note: Solution =
Solute + Solvent
STOP and THINK Using one of the equations above, find the % of NaCl in a saline solution prepared by
dissolving 15.0g of sodium chloride in 125g of water. (Remember: Solute + Solvent = Solution)
1. Rubbing alcohol is 70% isopropyl alcohol and 30% water.
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a.
Why are alcohol and water able to mix together so well?
b.
What volume of isopropyl alcohol would be needed to prepare 450mL of rubbing alcohol?
7. COLLIGATIVE PROPERTIES - https://youtu.be/9i26eK6xyNI
and part 2 - https://youtu.be/Y-wtTUPPeww
1. Colligative properties of a solution are properties that depend only on the ______________________ or
________________ of solute particles and NOT the nature of the solute or solvent.
2. When a ____________ is added to a _____________, some of the properties of the pure solvent are
changed. Three of those changes are vapor pressure, boiling point and freezing point.
Vapor pressure( lowers / raises ) as compared to the pure solvent. Therefore,
Boiling Point( elevates / depresses ) as compared to the pure solvent and
Freezing Point ( elevates / depresses ) as compared to the pure solvent.
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8. CALCULATION OF FREEZING POINT AND BOILING POINT OF AQUEOUS SOLUTIONS
Solutes in aqueous solutions affect the freezing point and boiling point of the solvent. Solutes in solution elevate
(increase) or depress (decrease) freezing point and boiling point compared to the freezing and boiling points of
the pure solvent. These changes can be calculated:
Change in freezing point = freezing point constant x molality x # of particles:
ΔTf = kf . m . i
Change in boiling point = boiling point constant x molality x # of particles:
ΔTb= kb . m . i
You already know how to calculate m (molality).
kf and kb are freezing and boiling point constants.
kf for water = 1.86°C/m
kb for water = 0.512°C/m
So, how do we determine “i” ? It is different depending on whether the compound is ionic or molecular:
For ionic compounds, the number of particles in solution result from the dissociation of ions in the
solvent. “i” also known as the Van ’t Hoff factor, is determined by the number of ions of an ionic
compound in one formula unit of that ionic compound.
For molecular compounds, the one particle is equal to one molecule of the compound.
Glucose dissolving in Water
How to calculate freezing point depression: Follow along and write as he does.
https://youtu.be/uIMrETHCAOM
Problem: A solution is made by dissolving 10.20g of glucose (C6H12O6) in 355g of water. What is the
freezing-point depression of the solvent if the freezing point constant is 1.86 C/m?
9
STOP AND THINK: Determine “i” for the following compounds.
a.
NaCl

H2O
Na+(aq) + Cl-(aq)
NOT: NaCl + H2O
b.
i =
i =2
c.
K2SO4 
d.
i =
e. Al(C2H3O2)3 
i =
CaCl2 
Pb(NO3)2 
i =
f.
C6H12O6
(Glucose)
i =
PRACTICE:
1.
Determine the freezing and boiling point of a solution prepared by dissolving 1.2 moles of glucose
(C6H12O6) in 875g of water.
a.
Is solute ionic?________
b. Calculate molality
c. Determine change in boiling/freezing point
d. Determine final boiling/freezing point
2.
Determine the freezing and boiling point of a solution prepared by dissolving 1.2 moles of sodium
sulfate in 875g of water.
a. Is solute ionic?________
b. Calculate molality
c. Determine change in boiling/freezing point
d. Determine final boiling/freezing point
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PART II - https://youtu.be/96oNrVnTk50
https://youtu.be/hiWlL8uqIC0
1. MOLARITY OF SOLIDS: moles solute per liter solution
[ ] = “the molarity of”
Molarity [M] =
𝐦𝐨𝐥𝐞𝐬 𝐬𝐨𝐥𝐮𝐭𝐞
𝐋 𝐬𝐨𝐥𝐮𝐭𝐢𝐨𝐧
a. Find the molarity of a solution prepared by dissolving 1.5moles of sodium nitrate in 350mL of solution.
b. Find the molarity of a solution prepared by dissolving 10.0g of sodium nitrate in 425mL of solution.
c. How many moles of sodium nitrate would be needed to prepare 250mL of a 0.80M solution?
d. What volume of 0.90M sodium nitrate can be made with 0.50moles of sodium nitrate?
e. What mass of sodium nitrate would you need to prepare 250mL of a 0.707M sodium nitrate solution,
starting with solid sodium nitrate and water.
f.
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What volume of 0.75M sodium nitrate solution can be prepared using 22.5g of sodium nitrate?
2.
DILUTION - https://youtu.be/v6dnEp58mVk
https://youtu.be/Zh40LDb3XSA
(Making a weak solution from a stronger one)
M1V1 = M2V2
PROBLEMS:
1. a. What volume of 12M HCl is needed to prepare 500mL of a 0.50M solution?
b. What volume of water would also be needed?
2. Enough water is added to 350mL of 0.75M KOH to bring the volume to 600mL. Find the molarity of the
new solution.
***3. Find the molarity of a solution prepared by adding 125mL of water to 375mL of 2.0M KNO3 solution.
TRY: 1. What volume of 5.0M NaBr solution is needed to prepare 250mL of 0.15M solution? What volume
of water is needed?
2. Enough water is added to 1.2L of 6.0M HNO3 to bring to volume to 2.5L. Find the molarity of the new
solution.
3. Find the molarity of a solution prepared by adding 25mL of water to 55mL of 0.40M KOH.
12
IN CLASS PRACTICE:
MOLARITY
1. How many moles of magnesium sulfate that must be dissolved in 250mL of water in order to prepare a
1.75M solution.
2. What mass of magnesium sulfate would be needed to prepare 1.5L of a 0.75M solution?
3. Find the molarity of a solution prepared by adding 5.00g of sodium hydroxide to 650mL of water.
4. What volume of 0.35M sodium hydroxide solution can be made using 15.0g of solid sodium hydroxide?
DILUTION
5. What volume of 0.75M potassium hydroxide solution is needed to make 350mL of a 0.15M solution? What
volume of water is also needed?
6. A student adds 250mL of water to 4.0L of 1.0M barium nitrate solution. What is the molarity of the
resulting solution?
13
3. REACTIONS IN SOLUTIONS
SINGLE REPLACEMENT: A + BX(aq) AX(aq) + B
http://preparatorychemistry.com/Zn_CuSO4_flash.htm
Mg(s) + HCl(aq)
1.
2.
Al(s) + CuSO4(aq)
3.
F2(g) + KBr(aq)
4.
Na(s) +
H2O(l)
DOUBLE REPLACEMENT:
AX(aq) + BY(aq) AY(aq) + BX(s)
http://preparatorychemistry.com/precipitation_flash.htm
precipitate:
1.
KBr(aq) + Cu(NO3)2(aq)
2.
Fe(NO2)3(aq) + Na3PO4(aq)
Rules for deciding which product is the solid:
All nitrates, nitrites and acetates dissolve in water – they are not the solid
Salts containing alkalai metals and ammonium dissolve in water – they are not the solid
If there is a heavy metal, it usually is part of the solid (if not with nitrate, nitrite or acetate)
14
4. SOLUTION STOICHIOMETRY
1.
What volume of 0.25M HNO3 is needed to react completely with 1.0g of magnesium ribbon?
REACTION:______________________________________________________________________
2a. A student prepares lead (II) chloride by reacting 0.55M lead (II) nitrite solution with excess sodium chloride
solution. What volume of 0.55M lead (II) nitrite solution would be needed in order to form 0.50g of lead
(II) chloride?
REACTION: ________________________________________________________________________
b. Using the reaction above, what mass of lead (II) chloride would precipitate if 120mL of
0.55M lead (II) nitrite solution react?
15
HW #1 WATER AND HYDROGEN BONDING
1. Draw a diagram of water molecules. Label the positive and negative poles, and use dotted lines to show
hydrogen bonding between the molecules.
2. What does electronegativity have to do with hydrogen bonding?
3. What elements, when joined with hydrogen, can be found in molecules that hydrogen bond?
4. Explain how hydrogen bonding in water leads the following properties:
Adhesive forces
Cohesive forces
high surface tension
high specific heat capacity (absorbs a lot of heat as it warms up)
solid water (ice) floats on liquid water
oil and water can’t mix
5. List two biological examples of hydrogen bonding.
a.
6.
16
b.
What is a surfactant? Give one example of a surfactant. (you will need to Google or use your textbook)
HW #2 Solubility (Polar vs. Nonpolar)
Check the appropriate columns as to whether the solute is soluble in a polar or nonpolar solvent.
SOLUTES
1. NaCl
2. I2
3. Ethanol
4. Benzene
5. Br2
6. KNO3
7. Toluene
8. Ca(OH)2
17
Water
SOLVENTS
CCl4
Alcohol
HW #3
18
HW #4
MORE SOLUBILITY CURVE
PRACTICE
1. What is the solubility of the following solutes in water?
a) NaCl at 60ºC =
b) KCl at 40ºC =
c) KNO3 at 20ºC =
2. Are the following solutions saturated or unsaturated?
Each solutioncontains 100 g of H20.
a) 2g of KCl at 30ºC =
b) 106g KNO3 at 60ºC =
c) 40g NaCl at 10ºC =
d) 150g KNO3 at 90ºC =
3. For each of the following solutions, explain how much of
the solutewill dissolve and how much will remain
undissolved at the bottom ofthe test tube?
a) 180 g of KNO3 in 100 g of water at 80ºC
b) 180 g of KNO3 in 100 g of water at 20ºC
c) 60 g of NaCl in 100 g of water at 60ºC
4. A saturated solution of KNO3 is formed from one hundred grams ofwater. If the saturated solution is cooled
from 90°C to 30°C, how many grams of precipitate are formed?
5. A saturated solution of KCl is formed from one hundred grams ofwater. If the saturated solution is cooled
from 90°C to 40°C, how many grams of precipitate are formed?
19
HW #5 MOLALITY AND MASS %
1. Determine the molality and mass % of solute in each of the solution below:
a. 10.0g of magnesium sulfate dissolved in 250g of water.
Molality =
Mass % =
b. 44g of glucose (C6H12O6) mixed with 450g of ethanol
Molality =
Mass % =
c.
350g of water mixed with 250g of ethanol(C2H5OH)
Molality =
Mass % =
2.
What volume of hydrogen peroxide is in a 250mL of 3% hydrogen peroxide solution?
3. What mass of sodium hydroxide must be added to 500g of water in order to prepare a 0.75m
solution?
20
HW #6 COLLIGATIVE PROPERTY PRACTICE
1. What is a colligative property?
2. Why is salt added to water when making pasta?
3. A student is making popsicles from Kool-Aid. He finds that the popsicles made with a strong Kool-Aid
solution take longer to freeze than the popsicles made with a weak solution. Use colligative properties to
explain why.
4. Use the information in the box below to solve problems a & b.
ΔTf = kf x m x i
Kf for water = 1.86°C/m
0.512°C/m
ΔTb= kb x m x i
Kb for water =
a. Find the boiling point and freezing point of a solution prepared by dissolving 25.0g of potassium
chloride in 500g of water. (Hint: first find the molality of the solution).
BP = _______
FP = _______
b. Find the boiling point and freezing point of a solution prepared by dissolving 0.75 moles of sugar in
500g of water.
BP = _______
21
FP = _______
HW #7
22
HW #8 MOLARITY PRACTICE PROBLEMS
SOLID
1. Determine the molarity of a solution prepared by dissolving 45.0g of CaCl2 in 450mL of water.
2. What mass of sodium nitrate must be added to 750mL of water in order to prepare a 0.55M solution?
3. What volume of 3.2M saline solution can be made using 2.0moles of salt?
DILUTION
4. What volume of 12.0M HCl solution is needed to prepare 550mL of a 0.75M solution? What volume of
water is also needed to prepare the solution?
5. Find the molarity of a solution prepared by adding 150mL of water to 250mL of 0.75M sodium hydroxide
solution.
**6. What volume of water was added to 500mL of 2.0M sulfuric acid solution if a 1.5M solution was
produced?
23
HW #9
REACTION WRITING PRACTICE
PART I: Identify the reaction type and complete each aqueous reaction given below. If there is a precipitate,
identify it.
________________________ a. K(s) +
ZnSO4(aq) 
________________________ b. Cl2(g) + NaBr(aq)
_________________________c. Zn(s)+Fe(NO3)3(aq)
_________________________ d. sodium + hydrochloric acid  (write out the complete reaction below)
___________________________e. solutions of magnesium nitrate and potassium fluoride are mixed
PART II: Review of Other Reaction Types: Label each reaction below as SYNTHESIS, DECOMPOSITION
OR COMBUSTION. Then write out the balanced equation for each reaction. If there is a precipitate, identify
it.
___________________________ a.
calcium carbonate  calcium oxide + carbon dioxide
____________________________ b. barium reacts with nitrogen to form barium nitride
____________________________ c. propane (C3H8) burns in oxygen to form carbon dioxide and water
24
HW #10
SOLUTION STOICHIOMETRY
1.A student places a copper wire in a solution of 1.2M silver nitrate, as we did in our chemical reactions lab.
Write the equation for the reaction that occurs on the line below. Assume that copper forms the Cu2+ ion when
it goes into solution.
________________________________________________________________________________
a.
What volume of 1.2M silver nitrate solution would be needed to react with 5.0g of copper?
b.
What mass of silver will precipitate if 20.0mL of 1.2M silver nitrate solution react?
c.
What mass of copper is needed to react with 10.0mL of 1.2M silver nitrate solution?
2. A student reacts 15.0mL of 0.80M sulfuric acid solution with excess iron (III) chloride solution. Write the
equation for the reaction that occurs on the line below.
___________________________________________________________________________________
a. What mass of iron(III) sulfate will be produced by the reaction?
b.
25
What mass of HCl will be produced by the reaction?
SOLUTION PREPARATION ACTIVITY
There is no write-up for this lab. You will be graded on the quality of the solutions you prepare.
PART I: SOLUTION PREPARATION FROM SOLID
You are to prepare 250mL of ________ M sodium carbonate solution. You will start with solid sodium
carbonate which you will find at the balance.
a. Calculate the mass of sodium carbonate that you must weigh out below.
WARNING: When you weigh out the mass of sodium carbonate that you calculated, do not weigh it directly
on the balance, and avoid contact with your skin. Use a weighing dish and a spatula. Clean it immediately
after use.
1. Clean and dry a beaker.
2. Add a volume less than your total volume of water to the clean, dry beaker. (I will explain).
3. Mass out the calculated mass of sodium carbonate. You will need to use the weighing dish.
4. Add the sodium carbonate to the water in the beaker. Stir until it dissolves. Use your water bottle to
“rinse in” the stirring rod.
5. Carefully pour the solution into your volumetric flask. Use your water bottle to “rinse in” your beaker.
6. Carefully bring the volume up to the meniscus. Cover the volumetric flask and mix well.
7. Clean and dry your well plate. Place 5 drops of your solution in one of the wells. I will testthe solution
in the well plate. Do not clean out your solution until I test it.
8. Clean all lab equipment. Wash the beaker, stirring rod and volumetric flask. RINSE TWICE WITH
TAP WATER.
26