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Chapter 8

Introduction to Solutions and Aqueous Reactions

Educators

ES
ZY
+ 38 more educators

Problem 1

What is an aqueous solution? What is the difference between the solute and the solvent?

Keenan M.
University of Miami

Problem 2

What is molarity? How is it useful?

Nicholas W.
Numerade Educator

Problem 3

Explain how a strong electrolyte, a weak electrolyte, and a nonelectrolyte differ.

Keenan M.
University of Miami

Problem 4

What is an acid? Explain the difference between a strong acid and a weak acid.

Nicholas W.
Numerade Educator

Problem 5

What does it mean for a compound to be soluble? Insoluble?

Keenan M.
University of Miami

Problem 6

What are the solubility rules? How are they useful?

Nicholas W.
Numerade Educator

Problem 7

Which cations and anions form compounds that are usually soluble? What are the exceptions? Which anions form compounds that are mostly insoluble? What are the exceptions?

Ronald P.
Numerade Educator

Problem 8

What is a precipitation reaction? Give an example.

Nicholas W.
Numerade Educator

Problem 9

How can you predict whether a precipitation reaction will occur upon mixing two aqueous solutions?

Keenan M.
University of Miami

Problem 10

Explain how a molecular equation, a complete ionic equation, and a net ionic equation differ.

Nicholas W.
Numerade Educator

Problem 11

What is the Arrhenius definition of a base?

Keenan M.
University of Miami

Problem 12

Explain how to name binary acids and oxyacids.

Nicholas W.
Numerade Educator

Problem 13

What is an acid-base reaction? Provide an example.

Keenan M.
University of Miami

Problem 14

Explain the principles behind an acid-base titration. What is an indicator?

Nicholas W.
Numerade Educator

Problem 15

What is a gas-evolution reaction? Provide an example.

Keenan M.
University of Miami

Problem 16

Which reactant types give rise to gas-evolution reactions?

Nicholas W.
Numerade Educator

Problem 17

What is an oxidation-reduction reaction? Provide an example.

Keenan M.
University of Miami

Problem 18

What are oxidation states? How can oxidation states be used to identify redox reactions?

Nicholas W.
Numerade Educator

Problem 19

What happens to a substance when it becomes oxidized? Reduced?

Keenan M.
University of Miami

Problem 20

In a redox reaction, which reactant is the oxidizing agent? The reducing agent?

Nicholas W.
Numerade Educator

Problem 21

Calculate the molarity of each solution.
a. 3.25 mol of LiCl in 2.78 L solution
b. 28.33 g C6H12O6 in 1.28 L of solution
c. 32.4 mg NaCl in 122.4 mL of solution

ES
Eugene S.
University of Minnesota - Twin Cities

Problem 22

Calculate the molarity of each solution.
a. 0.38 mol of LiNO3 in 6.14 L of solution
b. 72.8 g C2H6O in 2.34 L of solution
c. 12.87 mg KI in 112.4 mL of solution

ZY
Ziwei Y.
Numerade Educator

Problem 23

What is the molarity of NO3- in each solution?
a. 0.150 M KNO3
b. 0.150 M Ca(NO3)2
c. 0.150 M Al(NO3)3

JH
Jordan H.
Numerade Educator

Problem 24

What is the molarity of Cl- in each solution?
a. 0.200 M NaCl
b. 0.150 M SrCl2
c. 0.100 M AlCl3

do
David O.
Numerade Educator

Problem 25

How many moles of KCl are contained in each solution?
a. 0.556 L of a 2.3 M KCl solution
b. 1.8 L of a 0.85 M KCl solution
c. 114 mL of a 1.85 M KCl solution

RM
Rangika M.
Numerade Educator

Problem 26

What volume of 0.200 M ethanol solution contains each of the following amounts?
a. 0.45 mol ethanol
b. 1.22 mol ethanol
c. 1.2 * 10-2 mol ethanol

YZ
Yixiao Z.
Numerade Educator

Problem 27

A laboratory procedure calls for making 400.0 mL of a 1.1 M NaNO3 solution. What mass of NaNO3 (in g) do you need?

David C.
Numerade Educator

Problem 28

A chemist wants to make 5.5 L of a 0.300 M CaCl2 solution. What mass of CaCl2 (in g) should the chemist use?

Nicholas W.
Numerade Educator

Problem 29

If 123 mL of a 1.1 M glucose solution is diluted to 500.0 mL, what is the molarity of the diluted solution?

Lyniesha W.
Numerade Educator

Problem 30

If 3.5 L of a 4.8 M SrCl2 solution is diluted to 45 L, what is the molarity of the diluted solution?

SW
Samuel W.
Numerade Educator

Problem 31

To what volume should you dilute 50.0 mL of a 12 M stock HNO3 solution to obtain a 0.100 M HNO3 solution?

JH
Jason H.
Numerade Educator

Problem 32

To what volume should you dilute 25 mL of a 10.0 M H2SO4 solution to obtain a 0.150 M H2SO4 solution?

MC
Monique C.
University of Michigan - Ann Arbor

Problem 33

Consider the precipitation reaction:
2 Na3PO4(aq) + 3 CuCl2(aq)-Cu3(PO4)2(s) + 6 NaCl(aq)

What volume of 0.175 M Na3PO4 solution is necessary to completely react with 95.4 mL of 0.102 M CuCl2?

David C.
Numerade Educator

Problem 34

Consider the reaction:
Li2S(aq) + Co(NO3)2(aq)-2 LiNO3(aq) + CoS(s)

What volume of 0.150 M Li2S solution is required to completely react with 125 mL of 0.150 M Co(NO3)2?

Nicholas W.
Numerade Educator

Problem 35

What is the minimum amount of 6.0 M H2SO4 necessary to produce 25.0 g of H2(g) according to the reaction between aluminum and sulfuric acid?
2 Al(s) + 3 H2SO4(aq)-Al2(SO4)3(aq) + 3 H2(g)

Charotte M.
Numerade Educator

Problem 36

What molarity of ZnCl2 forms when 25.0 g of zinc completely reacts with CuCl2 according to the following reaction? Assume a final volume of 275 mL.
Zn(s) + CuCl2(aq)-ZnCl2(aq) + Cu(s)

Nicholas W.
Numerade Educator

Problem 37

You mix a 25.0 mL sample of a 1.20 M potassium chloride solution with 15.0 mL of a 0.900 M barium nitrate solution, and this precipitation reaction occurs:
2 KCl(aq) + Ba(NO3)2(aq)-BaCl2(s) + 2 KNO3(aq)
You collect and dry the solid BaCl2 and find it has a mass of 2.45 g. Determine the limiting reactant, the theoretical yield, and the percent yield.

Keenan M.
University of Miami

Problem 38

You mix a 55.0 mL sample of a 0.102 M potassium sulfate solution with 35.0 mL of a 0.114 M lead acetate solution, and this precipitation reaction occurs:
K2SO4(aq) + Pb(C2H3O2)2(aq)-2 KC2H3O2(aq) + PbSO4(s)

You collect and dry the solid PbSO4 and find it has a mass of 1.01 g. Determine the limiting reactant, the theoretical yield, and the percent yield.

Nicholas W.
Numerade Educator

Problem 39

For each compound (all water soluble), would you expect the resulting aqueous solution to conduct electrical current?
a. CsCl
b. CH3OH
c. Ca(NO2)2
d. C6H12O6

Keenan M.
University of Miami

Problem 40

Classify each compound as a strong electrolyte or nonelectrolyte.
a. MgBr2
b. C12H22O11
c. Na2CO3
d. KOH

David C.
Numerade Educator

Problem 41

Determine whether each compound is soluble or insoluble. If the compound is soluble, list the ions present in solution.
a. AgNO3
b. Pb(C2H3O2)2
c. KNO3
d. (NH4)2S

Keenan M.
University of Miami

Problem 42

Determine whether each compound is soluble or insoluble. For the soluble compounds, list the ions present in solution.
a. AgI
b. Cu3(PO4)2
c. CoCO3
d. K3PO4

Nicholas W.
Numerade Educator

Problem 43

Complete and balance each equation. If no reaction occurs, write NO REACTION.
a. LiI(aq) + BaS(aq)
b. KCl(aq) + CaS(aq)
c. CrBr2(aq) + Na2CO3(aq)
d. NaOH(aq) + FeCl3(aq)

Keenan M.
University of Miami

Problem 44

Complete and balance each equation. If no reaction occurs, write NO REACTION.
a. NaNO3(aq) + KCl(aq)
b. NaCl(aq) + Hg2(C2H3O2)2(aq)
c. (NH4)2SO4(aq) + SrCl2(aq)
d. NH4Cl(aq) + AgNO3(aq)

Nicholas W.
Numerade Educator

Problem 45

Write a molecular equation for the precipitation reaction that occurs (if any) when each pair of aqueous solutions is mixed. If no reaction occurs, write NO REACTION.
a. potassium carbonate and lead(II) nitrate
b. lithium sulfate and lead(II) acetate
c. copper(II) nitrate and magnesium sulfide
d. strontium nitrate and potassium iodide

Keenan M.
University of Miami

Problem 46

Write a molecular equation for the precipitation reaction that occurs (if any) when each pair of aqueous solutions is mixed. If no reaction occurs, write NO REACTION.
a. sodium chloride and lead(II) acetate
b. potassium sulfate and strontium iodide
c. cesium chloride and calcium sulfide
d. chromium(III) nitrate and sodium phosphate

Nicholas W.
Numerade Educator

Problem 47

Write balanced complete ionic and net ionic equations for each reaction.
a. HCl(aq) + LiOH(aq)-H2O(l) + LiCl(aq)
b. MgS(aq) + CuCl2(aq)-CuS(s) + MgCl2(aq)
c. NaOH(aq) + HNO3(aq)-H2O(l ) + NaNO3(aq)
d. Na3PO4(aq) + NiCl2(aq)- Ni3(PO4)2(s) + NaCl(aq)

Keenan M.
University of Miami

Problem 48

Write balanced complete ionic and net ionic equations for each reaction.
a. K2SO4(aq) + CaI2(aq)-CaSO4(s) + KI(aq)
b. NH4Cl(aq) + NaOH(aq)- H2O(l) + NH3(g) + NaCl(aq)
c. AgNO3(aq) + NaCl(aq)-AgCl(s) + NaNO3(aq)
d. HC2H3O2(aq) + K2CO3(aq)- H2O(l ) + CO2(g) + KC2H3O2(aq)

Nicholas W.
Numerade Educator

Problem 49

Mercury ions (Hg2 2+) can be removed from solution by precipitation with Cl-. Suppose that a solution contains aqueous Hg2(NO3)2. Write complete ionic and net ionic equations to show the reaction of aqueous Hg2(NO3)2 with aqueous sodium chloride to form solid Hg2Cl2 and aqueous sodium nitrate.

Keenan M.
University of Miami

Problem 50

Lead ions can be removed from solution by precipitation with sulfate ions. Suppose that a solution contains lead(II) nitrate. Write complete ionic and net ionic equations to show the reaction of aqueous lead(II) nitrate with aqueous potassium sulfate to form solid lead(II) sulfate and aqueous potassium nitrate.

Nicholas W.
Numerade Educator

Problem 51

Name each acid.
a. HI(aq)
b. HNO3(aq)
c. H2CO3(aq)

Keenan M.
University of Miami

Problem 52

Name each acid.
a. HCl(aq)
b. HClO2(aq)
c. H2SO4(aq)

Nicholas W.
Numerade Educator

Problem 53

Provide the formula for each acid.
a. hydrofluoric acid
b. hydrobromic acid
c. sulfurous acid

Keenan M.
University of Miami

Problem 54

Provide the formula for each acid.
a. phosphoric acid
b. hydrocyanic acid
c. chlorous acid

Nicholas W.
Numerade Educator

Problem 55

Write balanced molecular and net ionic equations for the reaction between hydrobromic acid and potassium hydroxide

Keenan M.
University of Miami

Problem 56

Write balanced molecular and net ionic equations for the reaction between nitric acid and calcium hydroxide.

Nicholas W.
Numerade Educator

Problem 57

Complete and balance each acid-base equation.
a. H2SO4(aq) + Ca(OH)2(aq)
b. HClO4(aq) + KOH(aq)
c. H2SO4(aq) + NaOH(aq)

Keenan M.
University of Miami

Problem 58

Complete and balance each acid-base equation.
a. HI(aq) + LiOH(aq)
b. HC2H3O2(aq) + Ca(OH)2(aq)
c. HCl(aq) + Ba(OH)2(aq)

Nicholas W.
Numerade Educator

Problem 59

Write balanced complete ionic and net ionic equations for each acid-base reaction.
a. HBr(aq) + NaOH(aq)
b. HF(aq) + NaOH(aq)
c. HC2H3O2(aq) + RbOH(aq)

David C.
Numerade Educator

Problem 60

Write balanced complete ionic and net ionic equations for each acid-base reaction.
a. HI(aq) + RbOH(aq)
b. HCHO2(aq) + NaOH(aq)
c. HC2H3O2(aq) + LiOH(aq)

EK
Emily K.
Numerade Educator

Problem 61

A 25.00-mL sample of an unknown HClO4 solution requires titration with 22.62 mL of 0.2000 M NaOH to reach the equivalence point. What is the concentration of the unknown HClO4 solution? The neutralization reaction is:

Keenan M.
University of Miami

Problem 62

A 30.00-mL sample of an unknown H3PO4 solution is titrated with a 0.100 M NaOH solution. The equivalence point is reached when 26.38 mL of NaOH solution is added. What is the concentration
of the unknown H3PO4 solution? The neutralization reaction is:

David C.
Numerade Educator

Problem 63

Complete and balance each gas-evolution equation.
a. HBr(aq) + NiS(s)
b. NH4I(aq) + NaOH(aq)
c. HBr(aq) + Na2S(aq)

Keenan M.
University of Miami

Problem 64

Complete and balance each gas-evolution equation.
a. HCl(aq) + KHCO3(aq)
b. HC2H3O2(aq) + NaHSO3(aq)
c. (NH4)2SO4(aq) + Ca(OH)2(aq)

Nicholas W.
Numerade Educator

Problem 65

Write a balanced equation for the reaction between perchloric acid and lithium carbonate.

Keenan M.
University of Miami

Problem 66

Write a balanced equation for the reaction between nitric acid and sodium sulfite.

Nicholas W.
Numerade Educator

Problem 67

Assign oxidation states to each atom in each element, ion, or compound.
a. Ag
b. Ag+
c. CaF2
d. H2S
e. CO3 2- f. CrO4 2-

Keenan M.
University of Miami

Problem 68

Assign oxidation states to each atom in each element, ion, or compound.
a. Cl2
b. Fe3+
c. CuCl2
d. CH4
e. Cr2O7 2-
f. HSO4-

Nicholas W.
Numerade Educator

Problem 69

What is the oxidation state of Cr in each compound?
a. CrO
b. CrO3 c.
Cr2O3

Keenan M.
University of Miami

Problem 70

What is the oxidation state of Cl in each ion?
a. ClO-
b. ClO2-
c. ClO3-
d. ClO4-

Marcia R P.
Numerade Educator

Problem 71

Determine whether or not each reaction is a redox reaction. For each redox reaction, identify the oxidizing agent and the reducing agent.
a. 4 Li(s) + O2(g)-2 Li2O(s)
b. Mg(s) + Fe2+(aq)-Mg2+(aq) + Fe(s)
c. Pb(NO3)2(aq) + Na2SO4(aq)-PbSO4(s) + 2 NaNO3(aq)
d. HBr(aq) + KOH(aq)-H2O(l) + KBr(aq)

Keenan M.
University of Miami

Problem 72

Determine whether or not each reaction is a redox reaction. For each redox reaction, identify the oxidizing agent and the reducing agent.
a. Al(s) + 3 Ag+(aq)-Al3+(aq) + 3 Ag(s)
b. SO3(g) + H2O(l)-H2SO4(aq)
c. Ba(s) + Cl2(g)-BaCl2(s)
d. Mg(s) + Br2(l)-MgBr2(s)

Nicholas W.
Numerade Educator

Problem 73

Determine whether each redox reaction occurs spontaneously in the forward direction.
a. Ni(s) + Zn2+(aq)-Ni2+(aq) + Zn(s)
b. Ni(s) + Pb2+(aq)-Ni2+(aq) + Pb(s)
c. Al(s) + 3 Ag+(aq)-3 Al3+(aq) + Ag(s)
d. Pb(s) + Mn2+(aq)-Pb2+(aq) + Mn(s)

Keenan M.
University of Miami

Problem 74

Determine whether each redox reaction occurs spontaneously in the forward direction.
a. Ca2+(aq) + Zn(s)-Ca(s) + Zn2+(aq)
b. 2 Ag+(aq) + Ni(s)-2 Ag(s) + Ni2+(aq)
c. Fe(s) + Mn2+(aq)-Fe2+(aq) + Mn(s)
d. 2 Al(s) + 3 Pb2+(aq)-2 Al3+(aq) + 3 Pb(s)

Nicholas W.
Numerade Educator

Problem 75

Suppose you wanted to cause Ni2+ ions to come out of solution as solid Ni. Which metal could you use to accomplish this?

Keenan M.
University of Miami

Problem 76

Suppose you wanted to cause Pb2+ ions to come out of solution as solid Pb. Which metal could you use to accomplish this?

Nicholas W.
Numerade Educator

Problem 77

Which metal in the activity series reduces Al3+ ions but not Na+ ions?

Keenan M.
University of Miami

Problem 78

Which metal in the activity series is oxidized with a Ni2+ solution but not with a Cr3+ solution?

Nicholas W.
Numerade Educator

Problem 79

The density of a 20.0% by mass ethylene glycol (C2H6O2) solution in water is 1.03 g>mL. Find the molarity of the solution.

Keenan M.
University of Miami

Problem 80

Find the percent by mass of sodium chloride in a 1.35 M NaCl solution. The density of the solution is 1.05 g>mL.

Nicholas W.
Numerade Educator

Problem 81

People often use sodium bicarbonate as an antacid to neutralize excess hydrochloric acid in an upset stomach. What mass of hydrochloric acid (in grams) can 2.5 g of sodium bicarbonate neutralize? (Hint: Begin by writing a balanced equation for the reaction between aqueous sodium bicarbonate and aqueous hydrochloric acid.)

Keenan M.
University of Miami

Problem 82

Toilet bowl cleaners often contain hydrochloric acid, which dissolves the calcium carbonate deposits that accumulate within a toilet bowl. What mass of calcium carbonate (in grams) can
3.8 g of HCl dissolve? (Hint: Begin by writing a balanced equation for the reaction between hydrochloric acid and calcium carbonate.)

Nicholas W.
Numerade Educator

Problem 83

A hydrochloric acid solution will neutralize a sodium hydroxide solution. Consider these molecular views of one beaker of HCl and four beakers of NaOH. Which NaOH beaker will just neutralize the HCl beaker? Begin by writing a balanced chemical equation for the neutralization reaction.

Keenan M.
University of Miami

Problem 84

These two beakers represent solutions of HCl and NaOH. Draw a third beaker showing the ions that remain after the reaction has gone to completion.

Nicholas W.
Numerade Educator

Problem 85

Predict the products and write a balanced molecular equation for each reaction. If no reaction occurs, write NO REACTION.
a. HCl(aq) + Hg2(NO3)2(aq)
b. KHSO3(aq) + HNO3(aq)
c. aqueous ammonium chloride and aqueous lead(II) nitrate
d. aqueous ammonium chloride and aqueous calcium hydroxide

Keenan M.
University of Miami

Problem 86

Predict the products and write a balanced molecular equation for each reaction. If no reaction occurs, write NO REACTION.
a. H2SO4(aq) + HNO3(aq)
b. Cr(NO3)3(aq) + LiOH(aq)
c. liquid pentanol (C5H12O) and gaseous oxygen
d. aqueous strontium sulfide and aqueous copper(II) sulfate

Nicholas W.
Numerade Educator

Problem 87

Hard water often contains dissolved Ca2+ and Mg2+ ions. One way to soften water is to add phosphates. The phosphate ion forms insoluble precipitates with calcium and magnesium ions, removing them from solution. A solution is 0.050 M in calcium chloride and 0.085 M in magnesium nitrate. What mass of sodium phosphate would have to be added to 1.5 L of this solution to completely eliminate the hard water ions? Assume a complete reaction.

Keenan M.
University of Miami

Problem 88

An acid solution is 0.100 M in HCl and 0.200 M in H2SO4. What volume of a 0.150 M KOH solution would completely neutralize all the acid in 500.0 mL of this solution?

Nicholas W.
Numerade Educator

Problem 89

Find the mass of barium metal (in grams) that must react with O2 to produce enough barium oxide to prepare 1.0 L of a 0.10 M solution of OH-. (Hint: Barium metal reacts with oxygen to form BaO; BaO reacts with water to form Ba(OH)2.)

Keenan M.
University of Miami

Problem 90

A solution contains Cr3+ ion and Mg2+ ion. The addition of 1.00 L of 1.51 M NaF solution causes the complete precipitation of these ions as CrF3(s) and MgF2(s). The total mass of the precipitate is 49.6 g. Find the mass of Cr3+ in the original solution.

Charotte M.
Numerade Educator

Problem 91

Find the volume of 0.110 M hydrochloric acid necessary to react completely with 1.52 g Al(OH)3.

Keenan M.
University of Miami

Problem 92

Find the volume of 0.150 M sulfuric acid necessary to react completely with 75.3 g sodium hydroxide.

Nicholas W.
Numerade Educator

Problem 93

Treatment of gold metal with BrF3 and KF produces Br2 and KAuF4, a salt of gold. Identify the oxidizing agent and the reducing agent in this reaction. What mass of the gold salt forms when a 73.5-g mixture of equal masses of all three reactants is prepared?

Keenan M.
University of Miami

Problem 94

We prepare a solution by mixing 0.10 L of 0.12 M sodium chloride with 0.23 L of a 0.18 M MgCl2 solution. What volume of a 0.20 M silver nitrate solution do we need to precipitate all the Cl- ion in the solution as AgCl?

Nicholas W.
Numerade Educator

Problem 95

A solution contains Ag+ and Hg2+ ions. The addition of 0.100 L of 1.22 M NaI solution is just enough to precipitate all the ions as AgI and HgI2. The total mass of the precipitate is 28.1 g. Find the mass of AgI in the precipitate.

Keenan M.
University of Miami

Problem 96

The water in lakes that have been acidified by acid rain (HNO3 and H2SO4) can be neutralized by a process called liming, in which limestone (CaCO3) is added to the acidified water. What mass of limestone (in kg) will completely neutralize a 15.2 billion-liter lake that is 1.8 * 10-5 M in H2SO4 and 8.7 * 10-6 M in HNO3?

Nicholas W.
Numerade Educator

Problem 97

Recall from Section 8.5 that sodium carbonate is often added to laundry detergents to soften hard water and make the detergent more effective. Suppose that a particular detergent mixture is designed to soften hard water that is 3.5 * 10-3 M in Ca2+ and 1.1 * 10-3 M in Mg2+ and that the average capacity of a washing machine is 19.5 gallons of water. If 0.65 kg detergent is required per load of laundry, what percentage (by mass) of the detergent should be sodium carbonate in order to completely precipitate all of the calcium and magnesium ions in an average load of laundry water?

Keenan M.
University of Miami

Problem 98

A solution contains one or more of the following ions: Ag+, Ca2+, and Cu2+. When you add sodium chloride to the solution, no precipitate forms. When you add sodium sulfate to the solution, a white precipitate forms. You filter off the precipitate and add sodium carbonate to the remaining solution, producing another precipitate. Which ions were present in the original solution? Write net ionic equations for the formation of each of the precipitates observed.

Charotte M.
Numerade Educator

Problem 99

A solution contains one or more of the following ions: Hg2 2+, Ba2+, and Fe2+. When potassium chloride is added to the solution, a precipitate forms. The precipitate is filtered off, and potassium sulfate is added to the remaining solution, producing no precipitate. When potassium carbonate is added to the remaining solution, a precipitate forms. Which ions were present in the original solution? Write net ionic equations for the formation of each of the precipitates observed.

Keenan M.
University of Miami

Problem 100

The circle shown here represents 1.0 L of a solution with a solute concentration of 1 M:

Explain what you would add (the amount of solute or volume of solvent) to the solution to obtain a solution represented by each diagram:

Nicholas W.
Numerade Educator

Problem 101

Consider the generic ionic compounds with the formulas A2X and BY2 and the following solubility rules: A2X soluble; BY2 soluble; AY insoluble; BX soluble. Let circles represent A+ ions, squares represent B2+ ions, triangles represent X2- ions, and diamonds represent Y- ions. Solutions of the two compounds (A2X and BY2) can be represented as follows:

Draw a molecular-level representation showing the result of mixing the two solutions (A2X and BY2) and write an equation to represent the reaction.

David C.
Numerade Educator

Problem 102

If you dissolve 27 g of sugar into 155 mL of water, what can you conclude about the mass and volume of the resulting solution? Assume a density of 1.00 g>mL for the water.
a. mass = 155 g; volume = 155 mL
b. mass = 182 g; volume = 155 mL
c. mass = 182 g; volume 7 155 mL
d. mass = 155 g; volume 7 155 mL

Nicholas W.
Numerade Educator

Problem 103

Explain the difference between the charge of an ion, such as a charge of 2- for an O2- ion, and the oxidation state of an atom, such as the -4 oxidation state of carbon in CH4.

Keenan M.
University of Miami

Problem 104

Write a detailed set of instructions for making two solutions: (1) 100.0 mL of 12-M NaOH from solid sodium hydroxide and (2) 1.00 L of 0.1 M NaOH from your first solution. You have in your lab: volumetric flasks marked to contain 100.0 mL and 1.000 L, a graduated cylinder, and a balance.

Nicholas W.
Numerade Educator

Problem 105

Review the solubility rules. Without referring back to the rules, have each group member list two ionic compounds that are expected to be soluble and two that are expected to be insoluble. Include at least one exception. Check the work of the other members of your group.

Keenan M.
University of Miami

Problem 106

Define and give an example of each of the following classes of reactions: precipitation, acid-base, gas evolution, redox (noncombustion), and combustion. Each group member can do one and then present the reaction to the group.

Nicholas W.
Numerade Educator

Problem 107

Using group members to represent atoms, ions, or electrons, act out the reaction Zn(s) + Fe2+(aq)-Zn2+(aq) + Fe(s). Which group member is oxidized? Which is reduced? Which is the oxidizing agent? Which is the reducing agent?

Keenan M.
University of Miami

Problem 108

In April 2014, in an effort to save money, officials in Flint, Michigan, changed their water source from Lake Huron to the Flint River. In subsequent months, residents began complaining about the quality of the water, and General Motors (which has an engine plant in Flint) stopped using the water in manufacturing because of its corrosiveness. That corrosiveness was causing problems that would soon fuel a national outrage. The water flowed through pipes to taps in homes, and as it flowed through the pipes, many of which contained lead, the corrosive water became contaminated
with lead. Routine monitoring of the tap water in select homes did not reveal the magnitude of the problem because samples were collected only after preflushing the tap (allowing the water to run for a time). A Virgina Tech professor and his students began an independent test of the water coming from Flint's taps and got much different results by analyzing the water that initially came from the taps (first draw). Their results-which showed elevated lead levels in the tap water-ultimately forced officials to switch back to the Lake Huron water source. The following table shows a set of data collected by the Virginia Tech team. The lead levels in water are expressed in units of parts per billion (ppb). 1 ppb = 1 g Pb>109 parts solution. Examine the data and answer the questions that follow.

a. Determine the average value of lead for first draw, 45-second flush, and 2-minute flush (round to three significant figures).
b. Do the data support the idea that running the tap water before taking a sample made the lead levels in the water appear lower? Why might this occur?
c. The EPA requires water providers to monitor drinking water at customer taps. If lead concentrations exceed 15 ppm in 10% or more of the taps sampled, the water provider must notify the customer and take steps to control the corrosiveness of the water. If the water provider in Flint had used first-draw
samples to monitor lead levels, would they have been required to take action by EPA requirements? If the Flint water provider used 2-min flush samples, would they have had to take action? Which drawing technique do you think more closely mimics the way residents actually use their water?
d. Using the highest value of lead from the first-draw data set, and assuming a resident drinks 2 L of water per day, calculate the mass of lead that the resident would consume over the course of one year. (Assume the water has a density of 1.0 g>mL.)

Nicholas W.
Numerade Educator