# Holt Chemistry

## Educators

Problem 1

What happens to a suspension when it is
allowed to stand over a period of time?

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Problem 2

If sugar is dissolved in water, which
component is the solute, and which
component is the solvent?

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Problem 3

Explain why milk is a colloid.

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Problem 4

What ratio does molarity express?

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Problem 5

Of the following three substances, which
two are miscible with one another: oil,
water, and ethanol?

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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?

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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 $12 . )$

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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.)

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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

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Problem 10

State Henry's law in your own words.

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Problem 11

Give an example of a nonelectrolyte.

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Problem 12

What kind of mixture is soap able to form
in order to make oil and water soluble?

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Problem 13

Name two colligative properties.

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Problem 14

What is the formula of a hydronium ion?

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Problem 15

What is a solution? How does it differ from
a colloid?

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Problem 16

What are the two components of a solution,
and how do they relate to each other?

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Problem 17

Explain how distillation can be used to
obtain drinking water from sea water.

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Problem 18

Explain how paper chromatography
separates the components in a solution.

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Problem 19

List these mixtures in order of increasing
particle size: muddy water, sugar water, sand
in water, and milk.

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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?

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Problem 21

Name a unit of concentration commonly
used to express small concentrations.

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Problem 22

State the following expression in words:
$\left[\mathrm{K}_{3} \mathrm{PO}_{4}\right]$

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Problem 23

A solution of $\mathrm{NaCl}$ is 1 $\mathrm{M.}$ Why is the
concentration of particles 2 $\mathrm{M} ?$

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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.

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Problem 25

Explain why vitamin $\mathrm{C}$ is soluble in water.

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Problem 26

Explain why gasoline is insoluble in water.

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Problem 27

Why do small solid crystals dissolve in liquid
more quickly than large crystals?

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Problem 28

Would ammonium chloride be considered
soluble in water?

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Problem 29

Would the compound BaSO $_{4}$ be considered
soluble in water?

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Problem 30

Would the compound $\mathrm{K}_{2} \mathrm{O}$ be considered
soluble in water?

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Problem 31

Why does warmer liquid dissolve less gas
than colder liquid?

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Problem 32

A solution of salt in water conducts
electricity, but a solution of sugar does not.
Explain why.

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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 $\mathrm{CaCl}_{2}$ .

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Problem 34

Explain why soap is a surfactant, a
detergent, and an emulsifying agent.

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Problem 35

Explain why acetic acid is considered a
weak electrolyte and why HCl is considered
a strong electrolyte.

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Problem 36

Draw a diagram of an oil droplet
suspended in soapy water.

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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?

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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?

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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?

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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?

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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?

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Problem 42

A solution contains 32.7 $\mathrm{g} \mathrm{H}_{3} \mathrm{PO}_{4}$ in 455 $\mathrm{mL}$
of solution. Calculate its molarity.

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Problem 43

How many moles of $\mathrm{AgNO}_{3}$ are needed to
prepare 0.50 $\mathrm{L}$ of a 4.0 $\mathrm{M}$ solution?

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Problem 44

What is the molarity of a solution that
contains 20.0 g $\mathrm{NaOH}$ in 2.00 $\mathrm{L}$ of solution?

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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.

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Problem 46

Calculate the mass of $\mathrm{NaOH}$ in 65.0 $\mathrm{mL}$ of
2.25 $\mathrm{M}$ solution.

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Problem 47

What mass of $\mathrm{HCl}$ is contained in 645 $\mathrm{mL}$
of 0.266 $\mathrm{M}$ solution?

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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?

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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?

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Problem 50

Calculate the mass of LiF in 100.0 $\mathrm{mL}$ of
0.100 $\mathrm{M}$ solution.

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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?

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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?
$$\begin{array}{c}{\mathrm{BaCl}_{2}(a q)+2 \mathrm{AgNO}_{3}(a q) \longrightarrow} \\ {2 \mathrm{AgCl}(s)+\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(a q)}\end{array}$$

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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?

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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?

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Problem 55

How many milliliters of 1.0 $\mathrm{M} \mathrm{AgNO}_{3}$ are
needed to provide 168.88 $\mathrm{g}$ of pure $\mathrm{AgNO}_{3} ?$

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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?

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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?

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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?

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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.)

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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?

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Problem 61

Imagine you are a sailor who must wash in
sea water. Which is better to use, soap or
synthetic detergent? Why?

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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.

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Problem 63

Why would a substance that contains only
ionic bonds not work as an emulsifying agent?

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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.)
a sample from the instructor, and perform

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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.

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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."

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Problem 67

What do the numbers on the
$y$ -axis represent?

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Problem 68

What does each curve on the graph
represent?

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Problem 69

Are most of the substances
represented on the graph more or
less soluble at higher
temperatures?

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Problem 70

Which salt is most soluble at $10^{\circ} \mathrm{C} ?$
at $60^{\circ} \mathrm{C} ?$ at $80^{\circ} \mathrm{C}$ ?

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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 $20^{\circ} \mathrm{C} ?$

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Problem 72

Which salt's solubility is most
strongly affected by changes in
temperature?

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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
and then QUIT, and then run the program $\mathrm{SOLUBIL}$ . For $\mathrm{L}_{1}$ press 2nd and LIST and choose SOL21.
$$\begin{array}{l}{\text { a. At what temperature would you expect }} \\ {\text { the solubility to be } 48.9 \text { g per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { b. At what temperature would you expect }} \\ {\text { the solubility to be } 35 \mathrm{g} \text { per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { c. What would you expect the solubility to }} \\ {\text { be at a temperature of } 100^{\circ} \mathrm{C} ?}\end{array}$$