# Holt Chemistry

## Educators

JB

### Problem 1

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

JB
Jason B.

### Problem 2

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

JB
Jason B.

### Problem 3

Explain why milk is a colloid.

JB
Jason B.

### Problem 4

What ratio does molarity express?

JB
Jason B.

### Problem 5

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

JB
Jason B.

### 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?

JB
Jason B.

### 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 $12 . )$

JB
Jason B.

### 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.)

JB
Jason B.

### 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.

JB
Jason B.

### Problem 10

State Henry's law in your own words.

JB
Jason B.

### Problem 11

Give an example of a nonelectrolyte.

JB
Jason B.

### Problem 12

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

JB
Jason B.

### Problem 13

Name two colligative properties.

JB
Jason B.

### Problem 14

What is the formula of a hydronium ion?

JB
Jason B.

### Problem 15

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

JB
Jason B.

### Problem 16

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

JB
Jason B.

### Problem 17

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

JB
Jason B.

### Problem 18

Explain how paper chromatography separates the components in a solution.

David C.

### Problem 19

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

JB
Jason B.

### 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?

Check back soon!

### Problem 21

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

David C.

### Problem 22

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

JB
Jason B.

### Problem 23

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

David C.

### 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.

David C.

### Problem 25

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

David C.

### Problem 26

Explain why gasoline is insoluble in water.

David C.

### Problem 27

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

David C.

### Problem 28

Would ammonium chloride be considered soluble in water?

David C.

### Problem 29

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

David C.

### Problem 30

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

David C.

### Problem 31

Why does warmer liquid dissolve less gas than colder liquid?

David C.

### Problem 32

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

David C.

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

David C.

### Problem 34

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

David C.

### Problem 35

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

David C.

### Problem 36

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

David C.

### 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?

David C.

### 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?

David C.

### 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?

David C.

### 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?

David C.

### 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?

David C.

### Problem 42

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

David C.

### Problem 43

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

David C.

### Problem 44

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

David C.

### 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.

David C.

### Problem 46

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

David C.

### Problem 47

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

David C.

### 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?

David C.

### 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?

David C.

### Problem 50

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

David C.

### 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?

David C.

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

David C.

### 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?

David C.

### 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?

David C.

### Problem 55

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

David C.

### 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?

David C.

### 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?

David C.

### 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?

David C.

### 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.)

David C.

### 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?

David C.

### Problem 61

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

David C.

### 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.

David C.

### Problem 63

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

David C.

### 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.

David C.

### 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.

Check back soon!

### 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."

David C.

### Problem 67

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

Check back soon!

### Problem 68

What does each curve on the graph represent?

David C.

### Problem 69

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

David C.

### Problem 70

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

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

David C.
Graphing Calculator Predicting Solubility from Tabular Data The graphing calculator can run a programthat 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. $$\begin{array}{l}{\text { a. At what temperature would you expect }} \\ {\text { the solubility to be } 48.9 \text { g per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { b. At what temperature would you expect }} \\ {\text { the solubility to be } 35 \mathrm{g} \text { per } 100 \mathrm{g} \mathrm{H}_{2} \mathrm{O} \text { ? }} \\ {\text { c. What would you expect the solubility to }} \\ {\text { be at a temperature of } 100^{\circ} \mathrm{C} ?}\end{array}$$