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 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

by adding more solute.

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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 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 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 27

Why do small solid crystals dissolve in liquid

more quickly than large crystals?

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Problem 30

Would the compound $\mathrm{K}_{2} \mathrm{O}$ be considered

soluble in water?

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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 35

Explain why acetic acid is considered a

weak electrolyte and why HCl is considered

a strong electrolyte.

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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.)

If your instructor approves your design, get

a sample from the instructor, and perform

your experiment.

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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 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

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.

$$\begin{array}{l}{\text { a. At what temperature would you expect }} \\ {\text { the solubility to be } 48.9 \text { g per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { b. At what temperature would you expect }} \\ {\text { the solubility to be } 35 \mathrm{g} \text { per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { c. What would you expect the solubility to }} \\ {\text { be at a temperature of } 100^{\circ} \mathrm{C} ?}\end{array}$$

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