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Chemistry Principles and Reactions

William L Masterton; Cecile N Hurley; Edward J Neth

Chapter 15

Complex lon and Precipitation Equilibria - all with Video Answers

Educators

Chapter Questions

03:11

Problem 1

At what concentration of ammonia is
(a) $\left[\mathrm{Cd}^{2+}\right]=\left[\mathrm{Cd}\left(\mathrm{NH}_{3}\right)_{4}^{2+}\right] ?$
(b) $\left[\mathrm{Co}^{2+}\right]=\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}^{2+}\right] ?$

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04:23

Problem 2

At what concentration of cyanide ion is
(a) $\left[\mathrm{Cd}^{2+}\right]=10^{-8} \times\left[\mathrm{Cd}(\mathrm{CN})_{4}^{2-}\right] ?$
(b) $\left[\mathrm{Fe}^{2+}\right]=10^{-20} \times\left[\mathrm{Fe}(\mathrm{CN})_{6}{ }^{4-}\right] ?$

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01:45

Problem 3

Consider the complex ion $\left[\mathrm{Ni}(e n)_{3}\right]^{2+} .$ Its $K_{\mathrm{f}}$ is $2.1 \times 10^{18}$. At what concentration of en is $67 \%$ of the $\mathrm{Ni}^{2+}$ converted to $\left[\mathrm{Ni}(e n)_{3}\right]^{2+} ?$

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01:40

Problem 4

Consider the complex ion $\left[\mathrm{Cr}(\mathrm{OH})_{4}\right]^{-}$. Its formation constant, $K_{\mathrm{f}}$, is $8 \times 10^{29} .$ At what pH will $85 \%$ of the $\mathrm{Cr}^{3+}$ be converted to $\left[\mathrm{Cr}(\mathrm{OH})_{4}\right]^{-2}$

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02:24

Problem 5

Write the equilibrium equation and the $K_{\mathrm{sp}}$ expression for each of the following.
(a) $\mathrm{Co}_{2} \mathrm{~S}_{3}$
(b) $\mathrm{PbCl}_{2}$
(c) $\mathrm{Zn}_{2} \mathrm{P}_{2} \mathrm{O}_{7}$
(d) $\mathrm{Sc}(\mathrm{OH})_{3}$

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02:31

Problem 6

Write the equilibrium equation and the $K_{\mathrm{sp}}$ expression for each of the following.
(a) $\mathrm{AgCl}$
(b) $\mathrm{Al}_{2}\left(\mathrm{CO}_{3}\right)_{3}$
(c) $\mathrm{MnS}_{2}$
(d) $\mathrm{Mg}(\mathrm{OH})_{2}$

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01:49

Problem 7

Write the equilibrium equations on which the following $K_{\mathrm{sp}}$ expressions are based.
(a) $\left[\mathrm{Hg}_{2}^{2+}\right]\left[\mathrm{Cl}^{-}\right]^{2}$
(b) $\left[\mathrm{Pb}^{2+}\right]\left[\mathrm{CrO}_{4}^{2-}\right]$
(c) $\left[\mathrm{Mn}^{4+}\right]\left[\mathrm{O}^{2-}\right]^{2}$
(d) $\left[\mathrm{Al}^{3+}\right]^{2}\left[\mathrm{~S}^{2-}\right]^{3}$

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01:51

Problem 8

Write the equilibrium equations on which the following $K_{\text {sp }}$ expressions are based.
(a) $\left[\mathrm{Pb}^{4+}\right]\left[\mathrm{O}^{2-}\right]^{2}$
(b) $\left[\mathrm{Hg}^{2+}\right]^{3}\left[\mathrm{PO}_{4}^{3-}\right]^{2}$
(c) $\left[\mathrm{Ni}^{3+}\right]\left[\mathrm{OH}^{-}\right]^{3}$
(d) $\left[\mathrm{Ag}^{+}\right]^{2}\left[\mathrm{SO}_{4}^{2-}\right]$

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03:08

Problem 9

Given $K_{\mathrm{sp}}$ and the equilibrium concentration of one ion, calculate the equilibrium concentration of the other ion.
(a) cadmium(II) hydroxide: $K_{\mathrm{sp}}=2.5 \times 10^{-14} ;\left[\mathrm{Cd}^{2+}\right]=1.5 \times 10^{-6} \mathrm{M}$
(b) copper(II) arsenate $\left(\mathrm{Cu}_{3}\left(\mathrm{AsO}_{4}\right)_{2}\right): K_{\mathrm{sp}}=7.6 \times 10^{-36} ;\left[\mathrm{AsO}_{4}^{3-}\right]=$
$2.4 \times 10^{-4} \mathrm{M}$
(c) zinc oxalate: $K_{\mathrm{sp}}=2.7 \times 10^{-8} ;\left[\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\right]=8.8 \times 10^{-3} \mathrm{M}$

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03:45

Problem 10

Follow the directions for Question 9 for the following compounds:
(a) lithium phosphate: $K_{\mathrm{sp}}=3.2 \times 10^{-9} ;\left[\mathrm{PO}_{4}^{3-}\right]=7.5 \times 10^{-4} \mathrm{M}$
(b) silver nitrite: $K_{\mathrm{sp}}=6.0 \times 10^{-4} ;\left[\mathrm{Ag}^{+}\right]=0.025 \mathrm{M}$
(c) tin(II) hydroxide: $K_{s p}=1.4 \times 10^{-28} ; \mathrm{pH}=9.35$

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02:40

Problem 11

Calculate the concentration of each of the following ions in equilibrium with $0.019 \mathrm{M} \mathrm{Br}^{-}$.
(a) $\mathrm{Pb}^{2+}$
(b) $\mathrm{Hg}_{2}^{2+}$
(c) $\mathrm{Ag}^{+}$

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03:08

Problem 12

Calculate the concentration of the following ions in equilibrium with $1.24 \times 10^{-4} \mathrm{M} \mathrm{Ca}^{2+}$
(a) $\mathrm{CO}_{3}^{2-}$
(b) $\mathrm{OH}^{-}$
(c) $\mathrm{PO}_{4}^{3-}$

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04:56

Problem 13

Fill in the blanks in the following table.

James Irizarry
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04:56

Problem 14

Fill in the blanks in the following table.

James Irizarry
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03:01

Problem 15

Calculate the molar solubility of the following compounds.
(a) $\mathrm{PbCl}_{2}$
(b) $\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}$
(c) $\mathrm{Ag}_{2} \mathrm{CO}_{3}$

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03:57

Problem 16

Calculate the molar solubility of the following compounds.
(a) $\mathrm{MgF}_{2}$
(b) $\mathrm{Fe}(\mathrm{OH})_{3}$
(c) $\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2}$

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03:34

Problem 17

Calculate the $K_{\mathrm{sp}}$ of the following compounds, given their molar solubilities.
(a) $\mathrm{ZnCO}_{3}, 1.21 \times 10^{-5} \mathrm{M}$
(b) $\mathrm{Ag}_{2} \mathrm{SO}_{4}, 0.014 \mathrm{M}$
(c) $\mathrm{Sr}_{3}\left(\mathrm{PO}_{4}\right)_{2}, 2.5 \times 10^{-7} \mathrm{M}$

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04:11

Problem 18

Calculate the $K_{\mathrm{sp}}$ of the following compounds given their molar solubilities.
(a) $\mathrm{MgC}_{2} \mathrm{O}_{4}, 9.2 \times 10^{-3} \mathrm{M}$
(b) $\mathrm{Mn}(\mathrm{OH})_{2}, 3.5 \times 10^{-5} \mathrm{M}$
(c) $\mathrm{Cd}_{3}\left(\mathrm{PO}_{4}\right)_{2}, 1.5 \times 10^{-7} \mathrm{M}$

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04:31

Problem 19

Calculate the solubility (in grams per liter) of silver chloride in the following.
(a) pure water
(b) $0.025 \mathrm{M} \mathrm{BaCl}_{2}$
(c) $0.17 \mathrm{M} \mathrm{AgNO}_{3}$

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05:08

Problem 20

Calculate the solubility (in grams per liter) of magnesium hydroxide in the following.
(a) pure water
(b) $0.041 \mathrm{M} \mathrm{Ba}(\mathrm{OH})_{2}$
(c) $0.0050 \mathrm{M} \mathrm{MgCl}_{2}$

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01:52

Problem 21

Lead azide, $\mathrm{Pb}\left(\mathrm{N}_{3}\right)_{2}$, is used as a detonator in car airbags. The impact of a collision causes $\mathrm{Pb}\left(\mathrm{N}_{3}\right)_{2}$ to be converted into an enormous amount of gas that fills the airbag. At $25^{\circ} \mathrm{C}$, a saturated solution of lead azide is prepared by dissolving $25 \mathrm{mg}$ in water to make $100.0 \mathrm{~mL}$ of solution. What is $K_{s p}$ for lead azide?

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01:59

Problem 22

A saturated solution of $\mathrm{Ni}(\mathrm{OH})_{2}$ can be prepared by dissolving $0.239 \mathrm{mg}$ of $\mathrm{Ni}(\mathrm{OH})_{2}$ in water to make $500.0 \mathrm{~mL}$ of solution. What is the $K_{\mathrm{sp}}$ for $\mathrm{Ni}(\mathrm{OH})_{2} ?$

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01:32

Problem 23

One gram of $\mathrm{PbCl}_{2}$ is dissolved in $1.0 \mathrm{~L}$ of hot water. When the solution is cooled to $25^{\circ} \mathrm{C}$, will some of the $\mathrm{PbCl}_{2}$ crystallize out? If so, how much?

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02:59

Problem 24

$K_{\mathrm{sp}}$ for silver acetate $\left(\mathrm{AgC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)$ at $80^{\circ} \mathrm{C}$ is estimated to be $2 \times 10^{-2}$. Ten grams of silver acetate are added to $1.0 \mathrm{~L}$ of water at $25^{\circ} \mathrm{C}$.
(a) Will all the silver acetate dissolve at $25^{\circ} \mathrm{C} ?$
(b) If the solution (assume the volume to be $1.0 \mathrm{~L}$ ) is heated to $80^{\circ} \mathrm{C}$,
will all the silver acetate dissolve?

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01:32

Problem 25

At $25^{\circ} \mathrm{C}, 100.0 \mathrm{~mL}$ of a $\mathrm{Ba}(\mathrm{OH})_{2}$ solution is prepared by dissolving $\mathrm{Ba}(\mathrm{OH})_{2}$ in an alkaline solution. At equilibrium, the saturated solution has $0.138 M \mathrm{Ba}^{2+}$ and a $\mathrm{pH}$ of $13.28 .$ Estimate $K_{\mathrm{sp}}$ for $\mathrm{Ba}(\mathrm{OH})_{2}$

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02:24

Problem 26

At $25^{\circ} \mathrm{C}, 10.24 \mathrm{mg}$ of $\mathrm{Cr}(\mathrm{OH})_{2}$ are dissolved in enough water to make $125 \mathrm{~mL}$ of solution. When equilibrium is established, the solution has a pH of 8. 49. Estimate $K_{\mathrm{sp}}$ for $\mathrm{Cr}(\mathrm{OH})_{2}$

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02:13

Problem 27

Barium nitrate is added to a solution of $0.025 \mathrm{M}$ sodium fluoride.
(a) At what concentration of $\mathrm{Ba}^{2+}$ does a precipitate start to form?
(b) Enough barium nitrate is added to make $\left[\mathrm{Ba}^{2+}\right]=0.0045 \mathrm{M}$. What percentage of the original fluoride ion has precipitated?

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03:28

Problem 28

Cadmium(11) chloride is added to a solution of potassium hydroxide with a pH of 9.62. $\left(K_{\mathrm{sp}} \mathrm{Cd}(\mathrm{OH})_{2}=2.5 \times 10^{-14}\right)$
(a) At what concentration of $\mathrm{Cd}^{2+}$ does a precipitate first start to form?
(b) Enough cadmium(II) chloride is added to make $\left[\mathrm{Cd}^{2+}\right]=0.0013 \mathrm{M}$. What is the $\mathrm{pH}$ of the resulting solution?
(c) What percentage of the original hydroxide ion is left in solution?

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03:05

Problem 29

Water from a well is found to contain $3.0 \mathrm{mg}$ of calcium ion per liter. If $0.50 \mathrm{mg}$ of sodium sulfate is added to one liter of the well water without changing its volume, will a precipitate form? What should $\left[\mathrm{SO}_{4}^{2-}\right]$ be to just start precipitation?

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03:41

Problem 30

Before lead in paint was discontinued, lead chromate was a common pigment in yellow paint. A 1.0-L solution is prepared by mixing $0.50 \mathrm{mg}$ of lead nitrate with $0.020 \mathrm{mg}$ of potassium chromate. Will a precipitate form? What should $\left[\mathrm{Pb}^{2+}\right]$ be to just start precipitation?

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06:36

Problem 31

A solution is prepared by mixing $13.00 \mathrm{~mL}$ of $0.0021 M$ aqueous $\mathrm{Hg}_{2}\left(\mathrm{NO}_{3}\right)_{2}$ with $25.0 \mathrm{~mL}$ of $0.015 M \mathrm{HCl}$. Assume that volumes are additive.
(a) Will precipitation occur?
(b) Calculate $\left[\mathrm{Hg}_{2}{ }^{2+}\right],\left[\mathrm{Cl}^{-}\right],$ and $\left[\mathrm{NO}_{3}^{-}\right]$ after equilibrium is established.

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06:49

Problem 32

A solution is prepared by mixing $45.00 \mathrm{~mL}$ of $0.022 \mathrm{M} \mathrm{AgNO}_{3}$ with $13.00 \mathrm{~mL}$ of $0.0014 \mathrm{M} \mathrm{Na}_{2} \mathrm{CO}_{3}$. Assume that volumes are additive.
(a) Will precipitation occur?
(b) Calculate $\left[\mathrm{Ag}^{+}\right],\left[\mathrm{CO}_{3}^{2-}\right],\left[\mathrm{Na}^{+}\right],$ and $\left[\mathrm{NO}_{3}^{-}\right]$ after equilibrium is established.

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02:44

Problem 33

A solution is $0.035 \mathrm{M}$ in $\mathrm{Na}_{2} \mathrm{SO}_{4}$ and $0.035 \mathrm{M}$ in $\mathrm{Na}_{2} \mathrm{CrO}_{4}$. Solid $\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}$ is added without changing the volume of the solution.
(a) Which salt, $\mathrm{PbSO}_{4}$ or $\mathrm{PbCrO}_{4}$, will precipitate first?
(b) What is $\left[\mathrm{Pb}^{2+}\right]$ when the salt in (a) first begins to precipitate?

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04:12

Problem 34

Solid lead nitrate is added to a solution that is $0.020 \mathrm{M}$ in $\mathrm{OH}^{-}$ and $\mathrm{SO}_{4}^{2-}$. Addition of the lead nitrate does not change the volume of the solution.
(a) Which compound, $\mathrm{PbSO}_{4}$ or $\mathrm{Pb}(\mathrm{OH})_{2}\left(K_{\mathrm{sp}}=2.8 \times 10^{-16}\right),$ will precipitate first?
(b) What is the $\mathrm{pH}$ of the solution when $\mathrm{PbSO}_{4}$ first starts to precipitate?

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03:16

Problem 35

A 65-mL solution of $0.40 \mathrm{M} \mathrm{Al}\left(\mathrm{NO}_{3}\right)_{3}$ is mixed with $125 \mathrm{~mL}$ of $0.17 \mathrm{M}$ iron(II) nitrate. Solid sodium hydroxide is then added without a change in volume.
(a) Which will precipitate first, $\mathrm{Al}(\mathrm{OH})_{3}$ or $\mathrm{Fe}(\mathrm{OH})_{2}$ ?
(b) What is $\left[\mathrm{OH}^{-}\right]$ when the first compound begins to precipitate?

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04:02

Problem 36

A solution is made up by adding $0.839 \mathrm{~g}$ of silver(I) nitrate and $1.024 \mathrm{~g}$ of lead(II) nitrate to enough water to make $492 \mathrm{~mL}$ of solution. Solid sodium chromate, $\mathrm{Na}_{2} \mathrm{CrO}_{4}$, is added without changing the volume of the solution.
(a) Which salt will precipitate first, $\mathrm{Ag}_{2} \mathrm{CrO}_{4}$ or $\mathrm{PbCrO}_{4} ?$
(b) What is the concentration of the chromate ion when the first salt starts to precipitate?

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04:06

Problem 37

A solution is made up by mixing $125 \mathrm{~mL}$ of $0.100 \mathrm{M} \mathrm{AuNO}_{3}$ and $225 \mathrm{~mL}$ of $0.049 \mathrm{M} \mathrm{AgNO}_{3}$. Twenty-five $\mathrm{mL}$ of a $0.0100 \mathrm{M}$ solution of $\mathrm{HCl}$ is then added. $K_{\mathrm{sp}}$ of $\mathrm{AuCl}=2.0 \times 10^{-13} .$ When equilibrium is established, will there be
no precipitate?
a precipitate of $\mathrm{AuCl}$ only?
a precipitate of $\mathrm{AgCl}$ only?
a precipitate of both $\mathrm{AgCl}$ and $\mathrm{AuCl}$ ?

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05:08

Problem 38

To a beaker with $500.0 \mathrm{~mL}$ of water are added $95 \mathrm{mg}$ of $\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}, 95 \mathrm{mg}$ of $\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2},$ and $100.0 \mathrm{mg}$ of $\mathrm{Na}_{2} \mathrm{CO}_{3} .$ After equilibrium is established, will there be
no precipitate?
a precipitate of $\mathrm{BaCO}_{3}$ only?
a precipitate of $\mathrm{CaCO}_{3}$ only?
a precipitate of both $\mathrm{CaCO}_{3}$ and $\mathrm{BaCO}_{3}$ ?

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02:24

Problem 39

Write net ionic equations for the reaction of $\mathrm{H}^{+}$ with
(a) $\mathrm{Cu}_{2} \mathrm{~S}$
(b) $\mathrm{Hg}_{2} \mathrm{Cl}_{2}$
(c) $\mathrm{SrCO}_{3}$
(d) $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}^{2+}$
(e) $\mathrm{Ca}(\mathrm{OH})_{2}$

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02:52

Problem 40

Write net ionic equations for the reactions of each of the following compounds with a strong acid.
(a) $\mathrm{CaF}_{2}$
(b) $\mathrm{CuCO}_{3}$
(c) $\mathrm{Ti}(\mathrm{OH})_{3}$
(d) $\mathrm{Sn}(\mathrm{OH})_{6}^{2-}$
(e) $\mathrm{Cd}\left(\mathrm{NH}_{3}\right)_{4}^{2+}$

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01:51

Problem 41

Write a net ionic equation for the reaction with ammonia by which
(a) silver chloride dissolves.
(b) aluminum ion forms a precipitate.
(c) copper(II) forms a complex ion.

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02:01

Problem 42

Write a net ionic equation for the reaction with ammonia by which
(a) $\mathrm{Cu}(\mathrm{OH})_{2}$ dissolves.
(b) $\mathrm{Cd}^{2+}$ forms a complex ion.
(c) $\mathrm{Pb}^{2+}$ forms a precipitate.

Eileen Sullivan
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01:35

Problem 43

Write a net ionic equation for the reaction with $\mathrm{OH}^{-}$ by which
(a) $\mathrm{Sb}^{3+}$ forms a precipitate.
(b) antimony(III) hydroxide dissolves when more $\mathrm{OH}^{-}$ is added.
(c) $\mathrm{Sb}^{3+}$ forms a complex ion.

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01:44

Problem 44

Write a net ionic equation for the reaction with $\mathrm{Al}^{3+}$ by which
(a) a complex ion forms when it reacts with $\mathrm{OH}^{-}$.
(b) a precipitate forms when it reacts with the phosphate ion.
(c) the precipitate formed with $\mathrm{OH}^{-}$ is dissolved by a strong acid.

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01:32

Problem 45

Write an overall net ionic equation and calculate $K$ for the reaction where $\mathrm{CuCl}\left(K_{\mathrm{sp}}=1.9 \times 10^{-7}\right)$ is dissolved by $\mathrm{NaCN}$ to form $\left[\mathrm{Cu}(\mathrm{CN})_{2}\right]^{-}$
$\left(K_{\mathrm{f}}=1.0 \times 10^{16}\right)$

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02:00

Problem 46

Write an overall net ionic equation and calculate $K$ for the reaction where $\mathrm{Co}(\mathrm{OH})_{2}\left(K_{\mathrm{sp}}=2 \times 10^{-16}\right)$ is dissolved by $\mathrm{HCl}$.

Eileen Sullivan
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02:16

Problem 47

Consider the reaction
$$
\mathrm{Zn}(\mathrm{OH})_{2}(s)+2 \mathrm{CN}^{-}(a q) \rightleftharpoons \mathrm{Zn}(\mathrm{CN})_{2}(s)+2 \mathrm{OH}^{-}(a q)
$$
(a) Calculate $K$ for the reaction. $\left(K_{\mathrm{sp}} \mathrm{Zn}(\mathrm{CN})_{2}=8.0 \times 10^{-12}\right)$
(b) Will $\mathrm{Zn}(\mathrm{CN})_{2}$ precipitate if $\mathrm{NaCN}$ is added to a saturated $\mathrm{Zn}(\mathrm{OH})_{2}$ solution?

Eileen Sullivan
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02:00

Problem 48

Consider the reaction
$$
\mathrm{BaF}_{2}(s)+\mathrm{SO}_{4}^{2-}(a q) \rightleftharpoons \mathrm{BaSO}_{4}(s)+2 \mathrm{~F}^{-}(a q)
$$
(a) Calculate $K$ for the reaction.
(b) Will $\mathrm{BaSO}_{4}$ precipitate if $\mathrm{Na}_{2} \mathrm{SO}_{4}$ is added to a saturated solution of $\mathrm{BaF}_{2} ?$

Eileen Sullivan
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04:07

Problem 49

Aluminum hydroxide reacts with an excess of hydroxide ions to form the complex ion $\mathrm{Al}(\mathrm{OH})_{4}^{-}$.
(a) Write an equation for this reaction.
(b) Calculate $K$.
(c) Determine the solubility of $\mathrm{Al}(\mathrm{OH})_{3}($ in $\mathrm{mol} / \mathrm{L})$ at $\mathrm{pH} 12.0$.

Eileen Sullivan
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03:37

Problem 50

Consider the reaction
$$
\mathrm{Cu}(\mathrm{OH})_{2}(s)+4 \mathrm{NH}_{3}(a q) \rightleftharpoons \mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}^{2+}(a q)+2 \mathrm{OH}^{-}(a q)
$$
(a) Calculate $K$ given that for $\mathrm{Cu}(\mathrm{OH})_{2} K_{\mathrm{sp}}=2 \times 10^{-19}$ and for $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}^{2+} K_{\mathrm{f}}=2 \times 10^{12}$
(b) Determine the solubility of $\mathrm{Cu}(\mathrm{OH})_{2}($ in $\mathrm{mol} / \mathrm{L})$ in $4.5 \mathrm{M} \mathrm{NH}_{3}$.

Eileen Sullivan
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03:03

Problem 51

Calculate the molar solubility of gold(I) chloride $\left(K_{s p}=2.0 \times 10^{-13}\right)$ in $0.10 \mathrm{M} \mathrm{NaCN}$. The complex ion formed is $\left[\mathrm{Au}(\mathrm{CN})_{2}\right]^{-}$ with $K_{\mathrm{f}}=2 \times 10^{38} .$
Ignore any other competing equilibrium systems.

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03:34

Problem 52

When excess $\mathrm{NaOH}$ is added to $\mathrm{Zn}(\mathrm{OH})_{2}$, the complex ion $\mathrm{Zn}(\mathrm{OH})_{4}{ }^{2-}$ is formed. Using Tables 15.1 and 15.2 , determine the molar solubility of $\mathrm{Zn}(\mathrm{OH})_{2}$ in $0.10 \mathrm{M} \mathrm{NaOH}$. Compare with the molar solubility of $\mathrm{Zn}(\mathrm{OH})_{2}$ in pure water.

Eileen Sullivan
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04:21

Problem 53

For the reaction
$$
\mathrm{CdC}_{2} \mathrm{O}_{4}(s)+4 \mathrm{NH}_{3}(a q) \rightleftharpoons \mathrm{Cd}\left(\mathrm{NH}_{3}\right)_{4}^{2+}(a q)+\mathrm{C}_{2} \mathrm{O}_{4}^{2-}(a q)
$$
(a) calculate $K .\left(K_{\mathrm{sp}}\right.$ for $\mathrm{CdC}_{2} \mathrm{O}_{4}$ is $\left.1.5 \times 10^{-8} .\right)$
(b) calculate $\left[\mathrm{NH}_{3}\right]$ at equilibrium when $2.00 \mathrm{~g}$ of $\mathrm{CdC}_{2} \mathrm{O}_{4}$ are dissolved in $1.00 \mathrm{~L}$ of solution.

Eileen Sullivan
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04:07

Problem 54

For the reaction
$$
\mathrm{Zn}(\mathrm{OH})_{2}(s)+4 \mathrm{CN}^{-}(a q) \rightleftharpoons \mathrm{Zn}(\mathrm{CN})_{4}{ }^{2-}(a q)+2 \mathrm{OH}^{-}(a q)
$$
(a) calculate $K$ for the reaction.
(b) find $\left[\mathrm{CN}^{-}\right]$ when $8.50 \mathrm{~g}$ of $\mathrm{Zn}(\mathrm{OH})_{2}$ are dissolved in $1.00 \mathrm{~L}$ of solution.

Eileen Sullivan
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01:50

Problem 55

What are the concentrations of $\mathrm{Cu}^{2+}, \mathrm{NH}_{3}$, and $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}^{2+}$ at equilibrium when $18.8 \mathrm{~g}$ of $\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}$ are added to $1.0 \mathrm{~L}$ of a $0.400 \mathrm{M}$ solution of aqueous ammonia? Assume that the reaction goes to completion and forms $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}^{2+}$

Sisi Gao
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01:48

Problem 56

For the system
$$
\text { hemoglobin } \cdot \mathrm{O}_{2}(a q)+\mathrm{CO}(g) \rightleftharpoons \text { hemoglobin } \cdot \mathrm{CO}(a q)+\mathrm{O}_{2}(g)
$$
$K=2.0 \times 10^{2} .$ What must be the ratio of $P_{\mathrm{CO}} / P_{\mathrm{O}_{2}}$ if $12.0 \%$ of the hemoglobin in the bloodstream is converted to the CO complex?

Eileen Sullivan
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04:45

Problem 57

Calcium ions in blood trigger clotting. To prevent that in donated blood, sodium oxalate, $\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4},$ is added to remove calcium ions according to the following equation.
$$
\mathrm{C}_{2} \mathrm{O}_{4}^{2-}(a q)+\mathrm{Ca}^{2+}(a q) \longrightarrow \mathrm{CaC}_{2} \mathrm{O}_{4}(s)
$$
Blood contains about $0.10 \mathrm{mg} \mathrm{Ca}^{2+} / \mathrm{mL}$. If a $250.0-\mathrm{mL}$ sample of donated blood is treated with an equal volume of $0.160 \mathrm{M} \mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4},$ estimate $\left[\mathrm{Ca}^{2+}\right]$ after precipitation. $\left(K_{\mathrm{sp}} \mathrm{CaC}_{2} \mathrm{O}_{4}=4 \times 10^{-9}\right)$

Kevin Zaborsky
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02:26

Problem 58

A saturated solution of calcium chromate $\left(\mathrm{CaCrO}_{4}\right)$ freezes at $-0.10^{\circ} \mathrm{C}$.
What is $K_{s p}$ for $\mathrm{CaCrO}_{4} ?$ Assume complete dissociation. The density of the solution is $1.0 \mathrm{~g} / \mathrm{mL}$

Eileen Sullivan
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03:52

Problem 59

A town adds 2.0 ppm of $\mathrm{F}^{-}$ ion to fluoridate its water supply. (Fluoridation of water reduces the incidence of dental caries). If the concentration of $\mathrm{Ca}^{2+}$ in the water is $3.5 \times 10^{-4} \mathrm{M},$ will a precipitate of $\mathrm{CaF}_{2}$ form when the water is fluoridated?

Cheryl Glor
Cheryl Glor
Numerade Educator
01:48

Problem 60

Predict what effect each of the following has on the position of the equilibrium
$$
\mathrm{PbCl}_{2}(s) \rightleftharpoons \mathrm{Pb}^{2+}(a q)+2 \mathrm{Cl}^{-}(a q) \quad \Delta H=23.4 \mathrm{~kJ}
$$
(a) addition of $1 \mathrm{M} \mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}$ solution
(b) increase in temperature
(c) addition of $\mathrm{Ag}^{+},$ forming $\mathrm{AgCl}$
(d) addition of $1 M$ hydrochloric acid

Eileen Sullivan
Eileen Sullivan
Numerade Educator
View

Problem 61

When $25.0 \mathrm{~mL}$ of $0.500 \mathrm{M}$ iron(II) sulfate is combined with $35.0 \mathrm{~mL}$ of $0.332 \mathrm{M}$ barium hydroxide, two different precipitates are formed.
(a) Write a net ionic equation for the reaction that takes place.
(b) Estimate the mass of the precipitates formed.
(c) What are the equilibrium concentrations of the ions in solution?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
05:23

Problem 62

Consider a $1.50-\mathrm{L}$ aqueous solution of $3.75 \mathrm{M} \mathrm{NH}_{3},$ where $17.5 \mathrm{~g}$ of $\mathrm{NH}_{4} \mathrm{Cl}$ are dissolved. To this solution, $5.00 \mathrm{~g}$ of $\mathrm{MgCl}_{2}$ are added.
(a) What is $\left[\mathrm{OH}^{-}\right]$ before $\mathrm{MgCl}_{2}$ is added?
(b) Will a precipitate form?
(c) What is $\left[\mathrm{Mg}^{2+}\right]$ after equilibrium is established?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:18

Problem 63

Marble is almost pure $\mathrm{CaCO}_{3}$. Acid rain has a devastating effect on marble statuary left outdoors. Assume that the reaction which occurs is
$$
\mathrm{CaCO}_{3}(s)+\mathrm{H}^{+}(a q) \longrightarrow \mathrm{Ca}^{2+}(a q)+\mathrm{HCO}_{3}^{-}(a q)
$$
Neglecting all other competing equilibria and using Tables 15.1 and 13.2 , calculate
(a) $K$ for the reaction.
(b) the molar solubility of $\mathrm{CaCO}_{3}$ in pure water.
(c) the molar solubility of $\mathrm{CaCO}_{3}$ in acid rainwater with a $\mathrm{pH}$ of 4.00 .

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:47

Problem 64

Consider the following solubility data for calcium oxalate $\left(\mathrm{CaC}_{2} \mathrm{O}_{4}\right):$
$$
\begin{array}{l}
K_{\mathrm{sp}} \text { at } 25^{\circ} \mathrm{C}=4 \times 10^{-9} \\
K_{\mathrm{sp}} \text { at } 95^{\circ} \mathrm{C}=1 \times 10^{-8}
\end{array}
$$
Five hundred $\mathrm{mL}$ of a saturated solution are prepared at $95^{\circ} \mathrm{C}$. How many milligrams of $\mathrm{CaC}_{2} \mathrm{O}_{4}$ will precipitate when the solution is cooled to $25^{\circ} \mathrm{C} ?$ (Assume that supersaturation does not take place.)

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:00

Problem 65

Consider three complexes of $\mathrm{Ag}^{+}$ and their formation constants, $K_{\mathrm{f}}$
$$
\begin{array}{lc}
\text { Complex Ion } & K_{f} \\
\hline \mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2^{+}} & 1.6 \times 10^{7} \\
\mathrm{Ag}(\mathrm{CN})_{2}^{-} & 5.6 \times 10^{18} \\
\mathrm{AgBr}_{2}^{-} & 1.3 \times 10^{7}
\end{array}
$$
Which statements are true?
(a) $\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}$ is more stable than $\mathrm{Ag}(\mathrm{CN})_{2}^{-}$.
(b) Adding a strong acid $\left(\mathrm{HNO}_{3}\right)$ to a solution that is $0.010 \mathrm{M}$ in $\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}$ will tend to dissociate the complex ion into $\mathrm{Ag}^{+}$ and $\mathrm{NH}_{4}^{+} .$
(c) Adding a strong acid $\left(\mathrm{HNO}_{3}\right)$ to a solution that is $0.010 \mathrm{M}$ in $\mathrm{AgBr}_{2}^{-}$ will tend to dissociate the complex ion into $\mathrm{Ag}^{+}$ and $\mathrm{Br}^{-}$.
(d) To dissolve AgI, one can add either $\mathrm{NaCN}$ or HCN as a source of the cyanide ion. Fewer moles of $\mathrm{NaCN}$ would be required.
(e) Solution $A$ is $0.10 M$ in $B r^{-}$ and contains the complex ion $\mathrm{AgBr}_{2}-$. Solution $\mathrm{B}$ is $0.10 \mathrm{M}$ in $\mathrm{CN}^{-}$ and contains the complex ion $\mathrm{Ag}(\mathrm{CN})_{2}-$. Solution B will have more particles of complex ion per particle of $\mathrm{Ag}^{+}$ than solution $\mathrm{A}$.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:08

Problem 66

The box below represents one liter of a saturated solution of the species
where squares represent the cation and circles represent the anion. Water molecules, though present, are not shown.

Complete the next three figures below by filling one-liter boxes to the right of the arrow, showing the state of the ions after water is added to form saturated solutions. The species represented to the left of the arrow is the solid form of the ions represented above. Do not show the water molecules.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:21

Problem 67

Using the same saturation data and species representation described in Question $66,$ complete the picture below.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:29

Problem 68

Which of the following statements are true?
(a) For an insoluble metallic salt, $K_{\mathrm{sp}}$ is always less than 1 .
(b) More $\mathrm{PbCl}_{2}$ can be dissolved at $100^{\circ} \mathrm{C}$ than at $25^{\circ} \mathrm{C}$. One can conclude that dissolving $\mathrm{PbCl}_{2}$ is an exothermic process.
(c) When strips of copper metal are added to a saturated solution of $\mathrm{Cu}(\mathrm{OH})_{2}$, a precipitate of $\mathrm{Cu}(\mathrm{OH})_{2}$ can be expected to form because of the common ion effect.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:58

Problem 69

Consider the insoluble salts $\mathrm{JQ}, \mathrm{K}_{2} \mathrm{R}, \mathrm{L}_{2} \mathrm{~S}_{3}, \mathrm{MT}_{2},$ and $\mathrm{NU}_{3} .$ They are formed from the metal ions $\mathrm{J}^{+}, \mathrm{K}^{+}, \mathrm{L}^{3+}, \mathrm{M}^{2+},$ and $\mathrm{N}^{3+}$ and the nonmetal ions $\mathrm{Q}^{-}, \mathrm{R}^{2-}, \mathrm{S}^{2-}, \mathrm{T}^{-},$ and $\mathrm{U}^{-}$. All the salts have the same $K_{\mathrm{sp}}, 1 \times 10^{-10}$, at $25^{\circ} \mathrm{C}$.
(a) Which salt has the highest molar solubility?
(b) Does the salt with the highest molar solubility have the highest solubility in g salt/100 g water?
(c) Can the solubility of each salt in $\mathrm{g} / 100 \mathrm{~g}$ water be determined from the information given? If yes, calculate the solubility of each salt in $\mathrm{g} / 100 \mathrm{~g}$ water. If no, why not?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:25

Problem 70

A plot of the solubility of a certain compound $\left(\mathrm{g} / 100 \mathrm{~g} \mathrm{H}_{2} \mathrm{O}\right)$ against temperature $\left({ }^{\circ} \mathrm{C}\right)$ is a straight line with a positive slope. Is dissolving that compound an exothermic process?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:33

Problem 71

Consider the equilibrium curve for AgCl shown below. Which of the following statements about a solution at point $A$ on the curve are true?
(a) The solution is saturated and at equilibrium.
(b) Addition of $\mathrm{NaCl}$ increases the concentration of $\mathrm{Cl}^{-}$ in solution.
(c) Addition of $\mathrm{NaCl}$ increases the concentration of $\mathrm{Ag}^{+}$ in solution.
(d) Addition of $\mathrm{Ag}^{+}$ results in the precipitation of $\mathrm{AgCl}$.
(e) Addition of solid $\mathrm{NaNO}_{3}$, to the solution without change in volume does not change $\left[\mathrm{Ag}^{+}\right]$ or $\left[\mathrm{Cl}^{-}\right]$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:01

Problem 72

Dissolving $\mathrm{CaCO}_{3}$ is an endothermic reaction. The following five graphs represent an experiment done on $\mathrm{CaCO}_{3} .$ Match the experiment to the graph.
(a) $\mathrm{HCl}$ is added.
(b) The temperature is increased.
(c) $\mathrm{CaCl}_{2}$ is added.
(d) $\mathrm{NaCl}$ is added.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:58

Problem 73

Ammonium chloride solutions are slightly acidic, so they are better solvents than water for insoluble hydroxides such as $\mathrm{Mg}(\mathrm{OH})_{2} .$ Find the solubility of $\mathrm{Mg}(\mathrm{OH})_{2}$ in moles per liter in $0.2 \mathrm{M} \mathrm{NH}_{4} \mathrm{Cl}$ and compare with the solubility in water. Hint: Find $K$ for the reaction
$$
\mathrm{Mg}(\mathrm{OH})_{2}(s)+2 \mathrm{NH}_{4}{ }^{+}(a q) \longrightarrow \mathrm{Mg}^{2+}(a q)+2 \mathrm{NH}_{3}(a q)+2 \mathrm{H}_{2} \mathrm{O}
$$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:10

Problem 74

What is the solubility of $\mathrm{CaF}_{2}$ in a buffer solution containing $0.30 \mathrm{M}$ $\mathrm{HCHO}_{2}$ and $0.20 \mathrm{M} \mathrm{NaCHO}_{2}$ ? Hint: Consider the equation
$$
\mathrm{CaF}_{2}(s)+2 \mathrm{H}^{+}(a q) \longrightarrow \mathrm{Ca}^{2+}(a q)+2 \mathrm{HF}(a q)
$$
and solve the equilibrium problem.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:51

Problem 75

What is the I $^{-}$ concentration just as AgCl begins to precipitate when $1.0 \mathrm{M} \mathrm{AgNO}_{3}$ is slowly added to a solution containing $0.020 \mathrm{M} \mathrm{Cl}^{-}$ and $0.020 \mathrm{M} \mathrm{I}^{-} ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
11:20

Problem 76

The concentrations of various cations in seawater, in moles per liter, are
$$
\begin{array}{llllll}
\hline \text { lon } & \mathrm{Na}^{+} & \mathrm{Mg}^{2+} & \mathrm{Ca}^{2+} & \mathrm{A}^{3+} & \mathrm{Fe}^{3+} \\
\text { Molarity }(\mathrm{M}) & 0.46 & 0.056 & 0.01 & 4 \times 10^{-7} & 2 \times 10^{-7} \\
\hline
\end{array}
$$
(a) At what $\left[\mathrm{OH}^{-}\right]$ does $\mathrm{Mg}(\mathrm{OH})_{2}$ start to precipitate?
(b) At this concentration, will any of the other ions precipitate?
(c) If enough $\mathrm{OH}^{-}$ is added to precipitate $50 \%$ of the $\mathrm{Mg}^{2+},$ what percentage of each of the other ions will precipitate?
(d) Under the conditions in (c), what mass of precipitate will be obtained from one liter of seawater?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
05:21

Problem 77

Consider the equilibrium
$\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}^{2+}(a q)+4 \mathrm{OH}^{-}(a q) \rightleftharpoons \mathrm{Zn}(\mathrm{OH})_{4}^{2-}(a q)+4 \mathrm{NH}_{3}(a q)$
(a) Calculate $K$ for this reaction.
(b) What is the ratio $\left[\mathrm{Zn}\left(\mathrm{NH}_{3}\right)_{4}{ }^{2+}\right] /\left[\mathrm{Zn}(\mathrm{OH})_{4}{ }^{2-}\right]$ in a solution $1.0 \mathrm{M}$ in
$\mathrm{NH}_{3} ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:02

Problem 78

Use the equilibrium constants in Appendix 1 to calculate $K$ for the reaction
$$
\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_{2}^{+}(a q)+2 \mathrm{H}^{+}(a q)+\mathrm{Cl}^{-}(a q) \rightleftharpoons \mathrm{AgCl}(s)+2 \mathrm{NH}_{4}^{+}(a q)
$$

Eileen Sullivan
Eileen Sullivan
Numerade Educator