Problem 1
What happens to a suspension when it is
allowed to stand over a period of time?
Problem 2
If sugar is dissolved in water, which
component is the solute, and which
component is the solvent?
Problem 5
Of the following three substances, which
two are miscible with one another: oil,
water, and ethanol?
Problem 6
One solution is made by dissolving sucrose
in water. Another solution is made by
dissolving NaCl in water. Which of these
dissolving processes involves dissociation?
Problem 7
What mass of ammonium chloride can be
added to 100 g of water at $20^{\circ} \mathrm{C}$ before the
solution becomes saturated? (See Figure $12 . )$
Problem 8
If 20 $\mathrm{g} \mathrm{KCl}$ is dissolved in 100 $\mathrm{g}$ of water at
$20^{\circ} \mathrm{C},$ is the solution unsaturated, saturated,
or supersaturated? (See Figure 12.)
Problem 9
Write a paragraph explaining
what happens to an ionic salt
in the following steps: it is dissolved in water, more of it than its solubility
amount is added to the solution, the solution is heated, the solution is cooled to room
temperature, and the solution is disturbed
by adding more solute.
Problem 12
What kind of mixture is soap able to form
in order to make oil and water soluble?
Problem 16
What are the two components of a solution,
and how do they relate to each other?
Problem 17
Explain how distillation can be used to
obtain drinking water from sea water.
Problem 19
List these mixtures in order of increasing
particle size: muddy water, sugar water, sand
in water, and milk.
Problem 20
A few drops of milk are added to a glass of
water, producing a cloudy mixture. The
water is still cloudy after standing in the
refrigerator for a week. What is this mixture
called?
Problem 21
Name a unit of concentration commonly
used to express small concentrations.
Problem 22
State the following expression in words:
$\left[\mathrm{K}_{3} \mathrm{PO}_{4}\right]$
Problem 23
A solution of $\mathrm{NaCl}$ is 1 $\mathrm{M.}$ Why is the
concentration of particles 2 $\mathrm{M} ?$
Problem 24
Describe how you would prepare 250.0 $\mathrm{mL}$
of a. 0.500 $\mathrm{M}$ solution of $\mathrm{NaCl}$ by using
apparatus found in a chemistry lab.
Problem 27
Why do small solid crystals dissolve in liquid
more quickly than large crystals?
Problem 30
Would the compound $\mathrm{K}_{2} \mathrm{O}$ be considered
soluble in water?
Problem 32
A solution of salt in water conducts
electricity, but a solution of sugar does not.
Explain why.
Problem 33
A 1 $\mathrm{M}$ solution of $\mathrm{NaCl}$ in water has a
freezing point that is $3.7^{\circ} \mathrm{C}$ lower than pure
water. Estimate what the freezing point
would be for a 1 $\mathrm{M}$ solution of $\mathrm{CaCl}_{2}$ .
Problem 35
Explain why acetic acid is considered a
weak electrolyte and why HCl is considered
a strong electrolyte.
Problem 37
A saturated solution of $\mathrm{PbCO}_{3}$ contains
0.00011 $\mathrm{g} \mathrm{PbCO}_{3}$ in 100 $\mathrm{g}$ of water. What is
this concentration in parts per million?
Problem 38
Community water supplies usually contain
1.0 ppm of sodium fluoride. A particular
water supply contains 0.0016 $\mathrm{g}$ of NaF in
1.60 $\mathrm{L}$ of water. Does it have enough NaF?
Problem 39
Most community water supplies have
0.5 ppm of chlorine added for purification
What mass of chlorine must be added to
100.0 L of water to achieve this level?
Problem 40
A 12.5 kg sample of shark meat contained
22 mg of methyl mercury, $\mathrm{CH}_{3} \mathrm{Hg}^{+} .$ Is this
amount within the legal limit of 1.00 ppm of
methyl mercury in meat?
Problem 41
If 15.55 g $\mathrm{NaOH}$ are dissolved in enough
water to make a 500.0 $\mathrm{mL}$ solution, what is
the molarity of the solution?
Problem 42
A solution contains 32.7 $\mathrm{g} \mathrm{H}_{3} \mathrm{PO}_{4}$ in 455 $\mathrm{mL}$
of solution. Calculate its molarity.
Problem 43
How many moles of $\mathrm{AgNO}_{3}$ are needed to
prepare 0.50 $\mathrm{L}$ of a 4.0 $\mathrm{M}$ solution?
Problem 44
What is the molarity of a solution that
contains 20.0 g $\mathrm{NaOH}$ in 2.00 $\mathrm{L}$ of solution?
Problem 45
Calculate the molarity of a $\mathrm{H}_{3} \mathrm{PO}_{4}$ solution
of 6.66 $\mathrm{g}$ in 555 $\mathrm{mL}$ of solution.
Problem 46
Calculate the mass of $\mathrm{NaOH}$ in 65.0 $\mathrm{mL}$ of
2.25 $\mathrm{M}$ solution.
Problem 47
What mass of $\mathrm{HCl}$ is contained in 645 $\mathrm{mL}$
of 0.266 $\mathrm{M}$ solution?
Problem 48
What is the molarity of a hydrochloric acid
solution that contains 18.3 $\mathrm{g} \mathrm{HCl}$ in
100.0 $\mathrm{mL}$ of solution?
Problem 49
A saturated solution of $\mathrm{NaCl}$ contains 36 $\mathrm{g}$
$\mathrm{NaCl}$ in 114 $\mathrm{mL}$ of solution. What is the
molarity of the solution?
Problem 50
Calculate the mass of LiF in 100.0 $\mathrm{mL}$ of
0.100 $\mathrm{M}$ solution.
Problem 51
How many grams of glucose, $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6},$ are
in 255 $\mathrm{mL}$ of a 3.55 $\mathrm{M}$ solution?
Problem 52
You mix 1.00 $\mathrm{L}$ of 2.00 $\mathrm{M} \mathrm{BaCl}_{2}$ with
1.00 $\mathrm{L}$ of 2.00 $\mathrm{M} \mathrm{AgNO}_{3} .$ What compounds
remain in solution, and what are their concentrations?
$$\begin{array}{c}{\mathrm{BaCl}_{2}(a q)+2 \mathrm{AgNO}_{3}(a q) \longrightarrow} \\ {2 \mathrm{AgCl}(s)+\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(a q)}\end{array}$$
Problem 53
How many milliliters of 18.0 $\mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}$ are
required to react with 250 $\mathrm{mL}$ of 2.50 $\mathrm{M}$
$\mathrm{Al}(\mathrm{OH})_{3}$ if the products are aluminum
sulfate and water?
Problem 54
If 75.0 $\mathrm{mL}$ of an AgNO $_{3}$ solution reacts with
enough Cu to produce 0.250 $\mathrm{g}$ Ag by single
displacement, what is the molarity of the
initial AgNO $_{3}$ solution if $\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}$ is the
other product?
Problem 55
How many milliliters of 1.0 $\mathrm{M} \mathrm{AgNO}_{3}$ are
needed to provide 168.88 $\mathrm{g}$ of pure $\mathrm{AgNO}_{3} ?$
Problem 56
What is the mass of potassium chromate,
$\mathrm{K}_{2} \mathrm{CrO}_{4},$ in 20.0 $\mathrm{mL}$ of 6.0 M solution?
Problem 57
Sodium ions in blood serum normally are
0.145 $\mathrm{M} .$ How many grams of sodium ions
are in 10.0 $\mathrm{mL}$ of serum?
Problem 58
A package of compounds used to achieve
rehydration in sick patients contains 20.0 g of
glucose, $\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}$ . When this material is diluted
to $1.00 \mathrm{L},$ what is the molarity of glucose?
Problem 59
Calcium phosphate, $\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2},$ is quite
cheap and causes few pollution problems.
Why is it not used to de-ice sidewalks?
(Hint: See Table 2 in Section 3.)
Problem 60
A calculation shows that a salt will have a
negative $\Delta H$ and a positive $\Delta S$ when it
dissolves. Is it actually soluble?
Problem 61
Imagine you are a sailor who must wash in
sea water. Which is better to use, soap or
synthetic detergent? Why?
Problem 62
Air pressure in an airplane cabin while in
flight is significantly lower than at sea level.
Explain in terms of Henry's law how this
affects the speed at which a carbonated
beverage, after opening, loses its fizz.
Problem 63
Why would a substance that contains only
ionic bonds not work as an emulsifying agent?
Problem 64
Design a solubility experiment that would
identify an unknown substance that is either
CsCl, RbCl, LiCl, NH $_{4}$ , KCl, or NaCl.
(Hint: You will need a solubility versus temperature graph for each of the salts.)
If your instructor approves your design, get
a sample from the instructor, and perform
your experiment.
Problem 65
Many reagent chemicals used in the lab are
sold in the form of concentrated aqueous
solutions, as shown in the table below.
Different volumes are diluted to 1.00 $\mathrm{L}$ to
make less-concentrated solutions. Create a computer spreadsheet that will calculate the
volume of concentrated reagent needed to
make 1.00 L solutions of any molar
concentration that you enter.
Problem 66
Use the following terms to create a concept
map: concentration, dissociates, electrical conductivity, solute, and solvent. Study the graph below, and answer the questions that follow.
For help in interpreting graphs, see Appendix $B$ , "Study Skills for Chemistry."
Problem 69
Are most of the substances
represented on the graph more or
less soluble at higher
temperatures?
Problem 70
Which salt is most soluble at $10^{\circ} \mathrm{C} ?$
at $60^{\circ} \mathrm{C} ?$ at $80^{\circ} \mathrm{C}$ ?
Problem 71
If you heat water to $80^{\circ} \mathrm{C},$ what
amount of $\mathrm{NaCl}$ could you
dissolve in it as compared to water
that is at $20^{\circ} \mathrm{C} ?$
Problem 72
Which salt's solubility is most
strongly affected by changes in
temperature?
Problem 73
Graphing Calculator
Predicting Solubility from Tabular Data
The graphing calculator can run a program
that graphs solubility data. Given solubility
measurements for KCl, you will use the data to
predict its solubility at various temperatures.
Go to Appendix C. If you are using a TI-83
Plus, you can download the program and
data sets and run the application as directed.
Press the APPS key on your calculator, then choose the application CHEMAPPS. Press 3
then highlight ALL on the screen, press 1 ,
then highlight LOAD and press 2 to load the data into your calculator. Press the keys 2nd
and then QUIT, and then run the program $\mathrm{SOLUBIL}$ . For $\mathrm{L}_{1}$ press 2nd and LIST and choose SOL21.
If you are using another calculator, your
teacher will provide you with keystrokes and
data sets to use.
$$\begin{array}{l}{\text { a. At what temperature would you expect }} \\ {\text { the solubility to be } 48.9 \text { g per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { b. At what temperature would you expect }} \\ {\text { the solubility to be } 35 \mathrm{g} \text { per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { c. What would you expect the solubility to }} \\ {\text { be at a temperature of } 100^{\circ} \mathrm{C} ?}\end{array}$$
