Chemistry Matter and Change

Thandi Buthelezi, Laurel Dingrando, Nicholas Hainen, Cheryl Wistrom, Dinah Zike

Chapter 17

Chemical Equilibrium - all with Video Answers

Educators

Chapter Questions

Problem 1

Write equilibrium constant expressions for these equilibria.

\begin{equation}
\begin{array}{l}{\text { a. } N_{2} O_{4}(g) \rightleftharpoons 2 N O_{2}(g)} \\ {\text { b. } 2 \mathrm{H}_{2} \mathrm{S}(9) \rightleftharpoons 2 \mathrm{H}_{2}(\mathrm{g})+\mathrm{S}_{2}(\mathrm{g}) \\ \text { c. } \mathrm{CO}(\mathrm{g})+3 \mathrm{H}_{2}(\mathrm{g}) \rightleftharpoons \mathrm{CH}_{4}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})} \\ {\text { d. } 4 \mathrm{NH}_{3}(\mathrm{g})+5 \mathrm{O}_{2}(\mathrm{g}) \rightleftharpoons 4 \mathrm{NO}(\mathrm{g})+6 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})} \\ {\text { e. } \mathrm{CH}_{4}(\mathrm{g})+2 \mathrm{H}_{2} \mathrm{S}(\mathrm{g}) \rightleftharpoons \mathrm{CS}_{2}(\mathrm{g})+4 \mathrm{H}_{2}(\mathrm{g}) }\end{array}
\end{equation}

Sara Ross

Sara Ross

Numerade Educator

Problem 2

Challenge Write the chemical equation that has the equilibrium
constant expression $K_{\mathrm{eq}}=\frac{[\mathrm{CO}]^{2}\left[\mathrm{O}_{2}\right]}{\left[\mathrm{CO}_{2}\right]^{2}}$.

Ly Tran

Numerade Educator

Problem 3

Write equilibrium constant expressions for these heterogeneous equilibria.
\begin{equation}
\begin{array}{l}{\text { a. } C_{10} \mathrm{H}_{8}(\mathrm{s}) \rightleftharpoons \mathrm{C}_{10} \mathrm{H}_{8}(\mathrm{g})} \\ {\text { b. } \mathrm{H}_{2} \mathrm{O}(1) \rightleftharpoons \mathrm{H}_{2} \mathrm{O}(\mathrm{g})} \\ {\text { c. } \mathrm{CaCO}_{3}(\mathrm{s}) \rightleftharpoons \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g})} \\ {\text { d. } \mathrm{C}(\mathrm{s})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \rightleftharpoons \mathrm{CO}(\mathrm{g})+\mathrm{H}_{2}(\mathrm{g})} \\ {\text { e. } \mathrm{FeO}(\mathrm{s})+\mathrm{CO}(\mathrm{g}) \rightleftharpoons \mathrm{Fe}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g})}\end{array}
\end{equation}

Sara Ross

Numerade Educator

Problem 4

Challenge Solid iron reacts with chlorine gas to form solid iron(llI) chloride $\left(\mathrm{FeCl}_{3}\right)$. Write the balanced equation and the equilibrium constant expression for the reaction.

Ly Tran

Numerade Educator

Problem 5

Calculate $K_{\text { eq }}$ for the equilibrium in Practice Problem 1a on page 601 using the data
$\left[\mathrm{N}_{2} \mathrm{O}_{4}\right]=0.0185 \mathrm{mol} / \mathrm{L}$ and $\left[\mathrm{NO}_{2}\right]=0.0627 \mathrm{mol} / \mathrm{L}$.

Ronald Prasad

Numerade Educator

Problem 6

Calculate $K_{\text { eq }}$ for the equilibrium in Practice Problem 1 $\mathrm{c}$ on page 601 using the data
$[\mathrm{CO}]=0.0613 \mathrm{mol} / \mathrm{L}$, $\left[\mathrm{H}_{2}\right]=0.1839 \mathrm{mol} / \mathrm{L}$, $\left[\mathrm{CH}_{4}\right]=0.0387 \mathrm{mol} / \mathrm{L}$, and $\left[\mathrm{H}_{2} \mathrm{O}\right]=0.0387 \mathrm{mol} / \mathrm{L}$.

Ly Tran

Numerade Educator

Problem 7

Challenge The reaction $\mathrm{COCl}_{2}(\mathrm{g}) \rightleftharpoons \mathrm{CO}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g})$ reaches equilibrium at 900 $\mathrm{K}$. $K_{\mathrm{eq}}$ is $8.2 \times 10^{-2} .$ If the equilibrium concentrations of $\mathrm{CO}$ and $\mathrm{Cl}_{2}$ are $0.150 \mathrm{M},$ what is the equilibrium concentration of $\mathrm{COCl}_{2} ?$

Sara Ross

Numerade Educator

Problem 8

Explain how the size of the equilibrium constant relates to the amount of product formed at equilibrium.

Ly Tran

Numerade Educator

Problem 9

Compare homogeneous and heterogeneous equilibria.

Sara Ross

Numerade Educator

Problem 10

List three characteristics a reaction mixture must have if is to attain a state of chemical equilibrium.

Ly Tran

Numerade Educator

Problem 11

Calculate Determine the value of $K_{\text { eq at }} 400$ K for this equation:
$\mathrm{PCl}_{5}(\mathrm{g}) \rightleftharpoons \mathrm{PCl}_{3}(\mathrm{g})+$ $\mathrm{Cl}_{2}(\mathrm{g})$ if $\left[\mathrm{PCl}_{5}\right]=0.135 \mathrm{mol} / \mathrm{L}$, $\left[\mathrm{PCl}_{3}\right]=0.550 \mathrm{mol} / \mathrm{L}$, and $\left[\mathrm{Cl}_{2}\right]=0.550 \mathrm{mol} / \mathrm{L}$

Sara Ross

Numerade Educator

Problem 12

Interpret Data The table below shows the value of the equilibrium constant for a reaction at three different temperatures. At which temperature is the concentration of the products the greatest? Explain your answer.

Ly Tran

Numerade Educator

Problem 13

Explain how a system at equilibrium responds to a stress and list factors that can be stresses on an equilibrium system.

Sara Ross

Numerade Educator

Problem 14

Explain how decreasing the volume of the reaction vessel affects each equilibrium.
\begin{equation} \text { a. } 250_{2}(g)+0_{2}(g) \rightleftharpoons 250_{3}(g) \quad \text { b. } H_{2}(g)+C I_{2}(g) \rightleftharpoons 2 H C l(g) \end{equation}

Ly Tran

Numerade Educator

Problem 15

Decide whether higher or lower temperatures will produce more $\mathrm{CH}_{3} \mathrm{CH} 0$ in the following equilibrium. $\mathrm{C}_{2} \mathrm{H}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \rightleftharpoons \mathrm{CH}_{3} \mathrm{CHO}(\mathrm{g}) \Delta H^{\circ}=-151 \mathrm{kJ}$

Sara Ross

Numerade Educator

Problem 16

Demonstrate The table below shows the concentrations of Substances $A$ and $B$
in two reaction mixtures. $A$ and $B$ react according to the equation 2$A \rightleftharpoons B; $ $K_{\mathrm{eq}}=200$ . Are the two mixtures at different equilibrium positions?

Ly Tran

Numerade Educator

Problem 17

Design a concept map that shows ways in which Le Chatelier's principle can be applied to increase the products in a system at equilibrium and to increase the reactants in such a system.

Sara Ross

Numerade Educator

Problem 18

At a certain temperature, $K_{\mathrm{eq}}=10.5$ for the equilibrium $\mathrm{CO}(\mathrm{g}) \rightleftharpoons \mathrm{CH}_{3} \mathrm{OH}(\mathrm{g})$.
Calculate the following concentrations:

\begin{equation}
\begin{array}{l}{\text { a. [CO] in an equilibrium mixture containing } 0.933 \mathrm{mol} / \mathrm{L} \mathrm{H}_{2} \text { and } 1.32 \mathrm{mol} / \mathrm{L} \mathrm{CH}_{3} \mathrm{OH}} \\ {\text { b. }\left[\mathrm{H}_{2}\right] \text { in an equilibrium mixture containing } 1.09 \mathrm{mol} / \mathrm{L} \mathrm{CO} \text { and } 0.325 \mathrm{mol} / \mathrm{L} \mathrm{CH}_{3} \mathrm{OH}} \\ {\text { c. }\left[\mathrm{CH}_{3} \mathrm{OH}\right] \text { in an equilibrium mixture containing } 0.0661 \mathrm{mol} / \mathrm{L} \mathrm{H}_{2} \text { and } 3.85 \mathrm{mol} / \mathrm{L} \text { CO }} \end{array}
\end{equation}

Ly Tran

Numerade Educator

Problem 19

Challenge In a generic reaction $A+B \rightleftharpoons C+D, 1.00$ mol of $A$ and 1.00 mol of $B$
are allowed to react in a $1-L$ flask until equilibrium is established. If the equilibrium concentration of $A$ is 0.450 $\mathrm{m} / \mathrm{L}$ , what is the equilibrium concentration of each of the other substances? What is $K_{\text { eq }} ?$

Sara Ross

Numerade Educator

Problem 20

Use the data in Table 17.3 to calculate the solubility in mol/L of the following ionic compounds at 298 $\mathrm{K}$.
\begin{equation}
\quad \text { a. } \mathrm{PbCrO}_{4} \quad \text { b. } \mathrm{AgCl} \quad \text { c. } \mathrm{CaCO}_{3}
\end{equation}

Ly Tran

Numerade Educator

Problem 21

Challenge The $K_{s p}$ of lead carbonate $\left(P b C O_{3}\right)$ is $7.40 \times 10^{-14}$ at 298 K What is the solubility of lead carbonate in $g / L ?$

Sara Ross

Numerade Educator

Problem 22

Use $K_{\mathrm{sp}}$ values from Table 17.3 to calculate the following.
\begin{equation}
\begin{array}{l}{\text { a. }\left[\mathrm{Ag}^{+}\right] \text { in a solution of } \mathrm{AgBr} \text { at equilibrium }} \\ {\text { b. }[\mathrm{F}-] \text { in a saturated solution of } \mathrm{CaF}_{2}} \\ {\text { c. }\left[\mathrm{Ag}^{+}\right] \text { in a solution of } \mathrm{Ag}_{2} \mathrm{CrO}_{4} \text { at equilibrium }}\end{array}
\end{equation}

Ly Tran

Numerade Educator

Problem 23

Calculate the solubility of $$\mathrm{Ag}_{3} \mathrm{PO}_{4}\left(K_{\mathrm{sp}}=2.6 \times 10^{-18}\right)$$

Sara Ross

Numerade Educator

Problem 24

Challenge The solubility of silver chloride $(\mathrm{AgCl})$ is $1.86 \times 10^{-4} \mathrm{g} / 100 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O}$ at 298 $\mathrm{K}$ Calculate the $K_{\mathrm{sp}}$ for AgCl.

Ly Tran

Numerade Educator

Problem 25

Use $K_{\mathrm{sp}}$ values from table 17.3 to predict whether a precipitate will form when equal volumes of the following solutions are mixed.
\begin{equation}
\begin{array}{l}{\text { a. } 0.10 M \mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2} \text { and } 0.030 M \mathrm{NaF}} \\ {\text { b. } 0.25 M \mathrm{K}_{2} \mathrm{SO}_{4} \text { and } 0.010 \mathrm{M} \mathrm{AgNO}_{3}}\end{array}
\end{equation}

Ronald Prasad

Numerade Educator

Problem 26

Challenge Will a precipitate form when 250 $\mathrm{mL}$ of 0.20$M \mathrm{MgCl}_{2}$ is added to 750 $\mathrm{mL}$ of 0.0025 $\mathrm{M} \mathrm{NaOH}$ ?

Ly Tran

Numerade Educator

Problem 27

List the information you would need in order to calculate the concentration of a product in a reaction mixture at equilibrium.

Sara Ross

Numerade Educator

Problem 28

Explain how to use the solubility product constant to calculate the solubility of a sparingly soluble ionic compound.

Ly Tran

Numerade Educator

Problem 29

Describe how the presence of a common ion reduces the solubility of an ionic compound.

Sara Ross

Numerade Educator

Problem 30

Explain the difference between $K_{\mathrm{sp}}$ and $Q_{\mathrm{sp} \cdot \text { Is }} Q_{\mathrm{sp}}$. an equilibrium constant?

Ly Tran

Numerade Educator

Problem 31

Calculate The $K_{\text { sp }}$ of magnesium carbonate $\left(\mathrm{Mg} \mathrm{CO}_{3}\right)$ is $2.6 \times 10^{-9} .$ What is the solubility of Mg CO $_{3}$ in pure water?

Sara Ross

Numerade Educator

Problem 32

Design an experiment based on solubilities to demonstrate which of two ions, $\mathrm{Mg}^{2+}$ or $\mathrm{Pb}^{2+},$ is contained in an aqueous solution. Solubility information about ionic compounds is given in Tables $R-3$ and $R-8$ on pages 969 and 974 respectively.

Ly Tran

Numerade Educator

Problem 33

Describe an equilibrium in everyday life that illustrates a state of balance between two opposing processes.

Sara Ross

Numerade Educator

Problem 34

Given the fact that the concentrations of reactants and products are not changing, why is the word dynamic used to describe chemical equilibrium?

Ly Tran

Numerade Educator

Problem 35

Explain how a person bailing out a row boat with a leak could represent a state of physical equilibrium.

Sara Ross

Numerade Educator

Problem 36

Does the following equation represent a homogeneous equilibrium or a heterogeneous equilibrium? Explain. your answer.
$$
\mathrm{H}_{2} \mathrm{O}(\mathrm{s}) \rightleftharpoons \mathrm{H}_{2} \mathrm{O}(1)
$$

Ly Tran

Numerade Educator

Problem 37

What is an equilibrium position?

Sara Ross

Numerade Educator

Problem 38

Explain how to write an equilibrium constant expression.

Ly Tran

Numerade Educator

Problem 39

Why should you pay attention to the physical states of reactants and products when writing equilibrium constant expressions?

Sara Ross

Numerade Educator

Problem 40

Why does a numerically large $K$ eq mean that the products are favored in an equilibrium system?

Ly Tran

Numerade Educator

Problem 41

What happens to $K_{\mathrm{eq}}$ for an equilibrium system if the equation for the reaction is rewritten in the reverse?

Sara Ross

Numerade Educator

Problem 42

How can an equilibrium system contain small and unchanging amounts of products yet have large amounts of reactants? What can you say about the relative size of $K_{\mathrm{eq}}$ for such an equilibrium?

Ly Tran

Numerade Educator

Problem 43

A system, which contains only molecules as reactants and products, is at equilibrium. Describe what happens to the concentrations of the reactants and products and what happens to individual reactant and product molecules.

Sara Ross

Numerade Educator

Problem 44

Write equilibrium constant expressions for these homogeneous equilibria.
\begin{equation}
\begin{array}{l}{\text { a. } 2 \mathrm{N}_{2} \mathrm{H}_{4}(\mathrm{g})+2 \mathrm{NO}_{2}(\mathrm{g}) \rightleftharpoons 3 \mathrm{N}_{2}(\mathrm{g})+4 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})} \\ {\text { b. } 2 \mathrm{NbCl}_{4}(\mathrm{g}) \rightleftharpoons \mathrm{NbCl}_{3}(\mathrm{g})+\mathrm{NbCl}_{5}(\mathrm{g})}\end{array}
\end{equation}

Ly Tran

Numerade Educator

Problem 45

Write equilibrium constant expressions for these heterogeneous equilibria.
\begin{equation}
\begin{array}{l}{\text { a. } 2 \mathrm{NaHCO}_{3}(\mathrm{s}) \rightleftharpoons \mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{s})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})+\mathrm{CO}_{2}(\mathrm{g})} \\ {\text { b. } \mathrm{C}_{6} \mathrm{H}_{6}(1) \rightleftharpoons \mathrm{C}_{6} \mathrm{H}_{6}(\mathrm{g})}\end{array}
\end{equation}

Sara Ross

Numerade Educator

Problem 46

Heating limestone $\left(\mathrm{CaCO}_{3}(\mathrm{s})\right)$ forms quicklime $(\mathrm{CaO}(\mathrm{s}))$ and carbon dioxide gas. Write the equilibrium constant expression for this reversible reaction.

Ly Tran

Numerade Educator

Problem 47

Suppose you have a cube of pure manganese metal measuring 5.25 $\mathrm{cm}$ on each side. You find that the mass of the cube is 1076.6 $\mathrm{g}$ . What is the molar concentration of manganese in the cube?

Sara Ross

Numerade Educator

Problem 48

$K_{\mathrm{eq}}$ is 3.63 for the reaction $\mathrm{A}+2 \mathrm{B} \rightleftharpoons \mathrm{C}$ . Table 17.5 shows the concentrations of the reactants and product in two different reaction mixtures at the same temperature. Determine whether both reactions are at equilibrium.

Ly Tran

Numerade Educator

Problem 49

When steam is passed over iron filings, solid iron(III) oxide and gaseous hydrogen are produced in a reversible reaction. Write the balanced chemical equation and the equilibrium constant expression for the reaction, which yields iron(III) oxide and hydrogen gas.

Sara Ross

Numerade Educator

Problem 50

What is meant by a stress on a reaction at equilibrium?

Ly Tran

Numerade Educator

Problem 51

How does Le Chatelier's principle describe an equilibrium's response to a stress?

Sara Ross

Numerade Educator

Problem 52

Why does removing a reactant cause an equilibrium shift to the left?

Ly Tran

Numerade Educator

Problem 53

When an equilibrium shifts to the right, what happens to each of the following?
\begin{equation}
\begin{array}{l}{\text { a. the concentration of the reactants }} \\ {\text { b. the concentration of the products }}\end{array}
\end{equation}

Sara Ross

Numerade Educator

Problem 54

Carbonated Beverages Use Le Chatelier's principle to explain how a shift in the equilibrium $\mathrm{H}_{2} \mathrm{CO}_{3}(\mathrm{aq}) \rightleftharpoons$ $\mathrm{H}_{2} \mathrm{O}(\mathrm{l})+\mathrm{CO}_{2}(\mathrm{g})$ causes a soft drink to go flat when its
container is left open.

Ly Tran

Numerade Educator

Problem 55

How would each of the following changes affect the equilibrium position of the system used to produce methanol from carbon monoxide and hydrogen?
$$\mathrm{CO}(\mathrm{g})+2 \mathrm{H}_{2}(\mathrm{g}) \rightleftharpoons \mathrm{CH}_{3} \mathrm{OH}(\mathrm{g})+ heat $$
$\begin{array}{l}{\text { a. adding CO to the system }} \\ {\text { b. cooling the system }} \\ {\text { c. adding a catalyst to the system }} \\ {\text { d. removing } \mathrm{CH}_{3} \mathrm{OH} \text { from the system }} \\ {\text { e. decreasing the volume of the system }}\end{array}$

Sara Ross

Numerade Educator

Problem 56

Explain how a temperature increase would affect the equilibrium represented by the following equation.
$$\mathrm{PCl}_{5}(\mathrm{g}) \rightleftharpoons \mathrm{PCl}_{3}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g})+ heat$$

Ly Tran

Numerade Educator

Problem 57

A liquid solvent for chlorine is poured into a flask in which the following reaction is at equilibrium:
$\mathrm{PCl}_{5}(\mathrm{g}) \rightleftharpoons \mathrm{PCl}_{3}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g})+$ heat. How is the equilibrium affected when some of the chlorine gas dissolves?

Supratim Pal

Numerade Educator

Problem 58

Figure 17.22 shows the following endothermic reaction at equilibrium at room temperature.
$$\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{2+}(\mathrm{aq})+4 \mathrm{Cl}^{-}(\mathrm{aq}) \rightleftharpoons \mathrm{CoCl}_{4}^{2-}(\mathrm{aq})+6 \mathrm{H}_{2} \mathrm{O}(1)$$
Given that $\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}^{2+}(\mathrm{aq})$ is pink and $\mathrm{CoCl}_{4}^{2-}(\mathrm{aq})$ is blue, what visual change would you expect to see if the flask were placed in an ice bath? Explain.

Ronald Prasad

Numerade Educator

Problem 59

For the equilibrium described in Question $54,$ what visual change would you expect to see if 10 $\mathrm{g}$ of solid potassium chloride were added and dissolved? Explain.

Sara Ross

Numerade Educator

Problem 60

Given two reactions at equilibrium:
\begin{equation}
\begin{array}{l}{\text { a. } \mathrm{N}_{2}(\mathrm{g})+3 \mathrm{H}_{2}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NH}_{3}(\mathrm{g})} \\ {\text { b. } \mathrm{H}_{2}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g}) \rightleftharpoons 2 \mathrm{HCl}(\mathrm{g}),}\end{array}
\end{equation}
explain why changing the volume of the systems alters the equilibrium position of a but has no effect on b.

Ly Tran

Numerade Educator

Problem 61

Would you expect the numerical value of $K_{\mathrm{eq}}$for the following equilibrium to increase or decrease with increasing temperature? Explain your answer.
$$\mathrm{PCl}_{5}(\mathrm{g}) \rightleftharpoons \mathrm{PCl}_{3}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g})+ heat$$

Sara Ross

Numerade Educator

Problem 62

Explain how you would regulate the pressure to favor the products in the following equilibrium system.
$$\mathrm{MgCO}_{3}(\mathrm{s}) \rightleftharpoons \mathrm{MgO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g})$$

Ly Tran

Numerade Educator

Problem 63

Ethylene $\left(C_{2} H_{4}\right)$ reacts with hydrogen to form ethane $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right) .$
$$\mathrm{C}_{2} \mathrm{H}_{4}(\mathrm{g})+\mathrm{H}_{2}(\mathrm{g}) \rightleftharpoons \mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{g})+$$
How would you regulate the temperature of this equilibrium in order to accomplish each of the following?
\begin{equation}
\begin{array}{l}{\text { a. increase the yield of ethane }} \\ {\text { b. decrease the concentration of ethylene }} \\ {\text { c. increase the amount of hydrogen in the system }}\end{array}
\end{equation}

Sara Ross

Numerade Educator

Problem 64

What does it mean to say that two solutions have a common ion? Give an example.

Ly Tran

Numerade Educator

Problem 65

Why are compounds such as sodium chloride usually not given $K_{s p}$ values?

Sara Ross

Numerade Educator

Problem 66

Xrays Why is barium sulfate a better choice than barium chloride for adding definition to X rays? At $26^{\circ} \mathrm{C}$ 37.5 $\mathrm{g}$ of $\mathrm{BaCl}_{2}$ can be dissolved in 100 $\mathrm{mL}$ of water.

Ly Tran

Numerade Educator

Problem 67

Explain what is happening in Figure 17.23 in terms of $Q_{\mathrm{sp}}$ and $K_{s p}$.

Sara Ross

Numerade Educator

Problem 68

Explain why a common ion lowers the solubility of an ionic compound.

Ly Tran

Numerade Educator

Problem 69

Describe the solution that results when two solutions are mixed and $Q_{s p}$ is found to equal $K_{\mathrm{sp}}$. Does a precipitate form?

Sara Ross

Numerade Educator

Problem 70

Write the $K_{s p}$ expression for lead chromate $\left(\mathrm{PbCrO}_{4}\right),$ and calculate its solubility in mol/L. $K_{\mathrm{sp}}=2.3 \times 10^{-13}$

Ly Tran

Numerade Educator

Problem 71

At $350^{\circ} \mathrm{C}, K_{\mathrm{eq}}=1.67 \times 10^{-2}$ for the reversible reaction $2 \mathrm{HI}(\mathrm{g}) \rightleftharpoons \mathrm{H}^{2}(\mathrm{g})+\mathrm{I}^{2}(\mathrm{g}) .$ What is the concentration of HI at equilibrium if $\left[\mathrm{H}^{2}\right]$ is $2.44 \times 10^{-3} M$ and $\left[\mathrm{I}^{2}\right]$ is $7.18 \times 10^{-5} \mathrm{M}$ ?

Sara Ross

Numerade Educator

Problem 72

$K_{\mathrm{sp}}$ for scandium fluoride $\left(\mathrm{ScF}_{3}\right)$ at 298 $\mathrm{K}$ is $4.2 \times 10^{-18}$. Write the chemical equation for the solubility equilibrium of scandium fluoride in water. What concentration of $S c^{3+}$ ions is required to cause a precipitate to form if the fluoride-ion concentration is 0.076$M ?$

Ly Tran

Numerade Educator

Problem 73

Will a precipitate form when 62.6 $\mathrm{mL}$ of 0.0322 $\mathrm{M} \mathrm{CaCl}_{2}$ and 31.3 $\mathrm{mL}$ of 0.0145 $\mathrm{M}$ NaOH are mixed? Use data from Table 17.4 on page $615 .$ Explain your logic.

Sara Ross

Numerade Educator

Problem 74

Manufacturing Ethyl acetate $\left(\mathrm{CH}_{3} \mathrm{COOCH}_{2} \mathrm{CH}_{3}\right), \mathrm{a}$ solvent used in making varnishes and lacquers, can be produced by the reaction between ethanol and acetic acid. The equilibrium system is described by the equation
$$\begin{array}{c}{\mathrm{CH}_{3} \mathrm{COOH}+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH} \rightleftharpoons} \\ \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad {\mathrm{CH}_{3} \mathrm{COOCH}_{2} \mathrm{CH}_{3}+\mathrm{H}_{2} \mathrm{O}}\end{array}$$
Calculate $K_{\mathrm{eq}}$ using these equilibrium concentrations:
$\left[\mathrm{CH}_{3} \mathrm{COOCH}_{2} \mathrm{CH}_{3}\right]=2.90 \mathrm{M},\left[\mathrm{CH}_{3} \mathrm{COOH}\right]=0.316 \mathrm{M}$
$\left[\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}\right]=0.313 M,$ and $\left[\mathrm{H}_{2} \mathrm{O}\right]=0.114 \mathrm{M}$

Ly Tran

Numerade Educator

Problem 75

Ethyl acetate $\left(\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{CH}_{3}\right)$ is produced in the
equilibrium system described by the following equation.
$$\begin{array}{c}{\mathrm{CH}_{3} \mathrm{COOH}+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH} \rightleftharpoons} \\ \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad {\mathrm{CH}_{3} \mathrm{COCCH}_{2} \mathrm{CH}_{3}+\mathrm{H}_{2} \mathrm{O}}\end{array}$$
Why does the removal of water result in the production of more ethyl acetate?

Sara Ross

Numerade Educator

Problem 76

How would these equilibria be affected by decreasing the temperature?
\begin{equation}
\begin{array}{l}{\text { a. } 2 \mathrm{O}_{3}(\mathrm{g}) \rightleftharpoons 3 \mathrm{O}_{2}(\mathrm{g})+\text { heat }} \\ {\text { b. heat }+\mathrm{H}_{2}(\mathrm{g})+\mathrm{F}_{2}(\mathrm{g}) \rightleftharpoons 2 \mathrm{HF}(\mathrm{g})}\end{array}
\end{equation}

Ly Tran

Numerade Educator

Problem 77

How would simultaneously increasing the temperature and volume of the system affect these equilibria?
\begin{equation}
\begin{array}{l}{\text { a. } 2 \mathrm{O}_{3}(\mathrm{g}) \rightleftharpoons 3 \mathrm{O}_{2}(\mathrm{g})+\text { heat }} \\ {\text { b. heat }+\mathrm{N}_{2}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})}\end{array}
\end{equation}

Sara Ross

Numerade Educator

Problem 78

The solubility product constant for lead(II) arsenate $\left(\mathrm{Pb}_{3}\left(\mathrm{AsO}_{4}\right)_{2}\right)$ is $4.0 \times 10^{-36}$ at 298 $\mathrm{K}$ . Calculate the molar
solubility of the compound at this temperature.

Ly Tran

Numerade Educator

Problem 79

Evaluate this statement: A low value for $K_{\text { eq }}$ means that both the forward and reverse reactions are occurring slowly.

Sara Ross

Numerade Educator

Problem 80

Food Flavoring Benzaldehyde, known as artificial almond oil, is used in food flavorings. What is the molar concentration of benzaldehyde $\left(\mathrm{C}_{7} \mathrm{H}_{6} \mathrm{O}\right)$ at $298 \mathrm{K},$ when its density is 1.043 $\mathrm{g} / \mathrm{mL}$ ?

Ly Tran

Numerade Educator

Problem 81

In the equilibrium system $\mathrm{N}_{2} \mathrm{O}_{4}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NO}_{2}(\mathrm{g}), \mathrm{N}_{2} \mathrm{O}_{4}$ is colorless and $\mathrm{NO}_{2}$ is reddish-brown. Explain the different colors of the equilibrium system as shown in Figure 17.24.

Sara Ross

Numerade Educator

Problem 82

Describe the process by which adding potassium hydroxide to a saturated aluminum hydroxide solution reduces the concentration of aluminum ions. Write the solubility equilibrium equation and solubility product constant expression for a saturated aqueous solution of aluminum hydroxide.

Ly Tran

Numerade Educator

Problem 83

At $298 \mathrm{K}, K_{\mathrm{sp}}$ for cadmium iodate $\left(\mathrm{Cd}\left(\mathrm{IO}_{3}\right)_{2}\right)$ equals $2.3 \times 10^{-8} .$ What are the molar concentrations of cadmium ions and iodate ions in a saturated solution at 298 $\mathrm{K?}$

Sara Ross

Numerade Educator

Problem 84

Analyze Suppose that an equilibrium system at a given temperature has a $K_{\text { eq }}$ equal to $1.000 .$ Evaluate the possibility that such a system is made up of 50$\%$ reactants and 50$\%$ products. Explain your answer.

David Collins

Numerade Educator

Problem 85

Evaluate Imagine that you are a chemical engineer designing a production facility for a particular process. The process will utilize a reversible reaction that reaches a state of equilibrium. Analyze the merits of a continuous-flow process or a batch process for such a reaction and determine which is preferable. As a reaction proceeds in a continuous-flow process, reactants are continuously introduced into the reaction chamber and products are continuously removed from the chamber. In a batch process, the reaction chamber is charged with reactants, the reaction is allowed to occur, and the chamber is later emptied of all materials.

Sara Ross

Numerade Educator

Problem 86

Interpret Data What compound would precipitate first if a 0.500$M$ sodium fluoride solution were added gradually to a solution already containing 0.500$M$ concentrations of both barium ions and magnesium ions? Use the data in Table $17.6 .$ Write the solubility equilibrium equations and solubility product constant expressions for both compounds. Explain your answer.

Ly Tran

Numerade Educator

Problem 87

Apply Smelling salts, sometimes used to revive a person who is unconscious, are made of ammonium carbonate. The equation for the endothermic decomposition of ammonium carbonate is as follows.
$$\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3}(\mathrm{s}) \rightleftharpoons 2 \mathrm{NH}_{3}(\mathrm{g})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})$$
Would you expect smelling salts to work as well on a cold winter day as on a warm summer day? Explain your answer.

Sara Ross

Numerade Educator

Problem 88

Recognize Cause and Effect Suppose you have 12.56 $\mathrm{g}$ of a mixture made up of sodium chloride and barium chloride. Explain how you could use a precipitation reaction to determine how much of each compound the mixture contains.

Ly Tran

Numerade Educator

Problem 89

Compare and Contrast Which of the two solids, calcium phosphate or iron(III) phosphate, has the greater molar solubility? $K_{\mathrm{sp}}\left(\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}\right)=1.2 \times 10^{-29}; $
$K_{\mathrm{sp}}\left(\mathrm{FePO}_{4}\right)=1.0 \times 10^{-22} .$ Which compound has the
greater solubility, expressed in grams per liter?

Sara Ross

Numerade Educator

Problem 90

Synthesis of Phosgene Phosgene (COCl_ ) is a toxic gas that is used in the manufacture of certain dyes, pharmaceuticals, and pesticides. Phosgene can be produced by the reaction between carbon monoxide and chlorine described by the equation $\mathrm{CO}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g}) \rightleftharpoons \mathrm{COCl}_{2}(\mathrm{g}) .$ Initially 1.0000 mol $\mathrm{CO}$ and 1.0000 $\mathrm{mol} \mathrm{Cl}_{2}$ are introduced into a 10.00 -L reaction vessel. When equilibrium is established, both of their molar concentrations are found to be 0.0086 $\mathrm{mol} / \mathrm{L}$ . What is the molar concentration of phosgene at equilibrium? What is $K_{\mathrm{eq}}$ for the system?

Ly Tran

Numerade Educator

Problem 91

Explain the general trend in ionization energy as you go from left to right along Periods $1-5$ of the periodic table. (Chapter 6$)$

Sara Ross

Numerade Educator

Problem 92

How are the lengths of covalent bonds related to their strength? (Chapter 8$)$

Ly Tran

Numerade Educator

Problem 93

How are the chemical bonds in $\mathrm{H}_{2}, \mathrm{O}_{2},$ and $\mathrm{N}_{2}$ different?
(Chapter 8$)$

Sara Ross

Numerade Educator

Problem 94

How can you tell if a chemical equation is balanced? (Chapter 9$)$

Ly Tran

Numerade Educator

Problem 95

What mass of carbon must burn to produce 4.56 $\mathrm{L} \mathrm{CO}_{2}$ gas at STP? (Chapter 11)
$$\mathrm{C}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) \rightarrow \mathrm{CO}_{2}(\mathrm{g})$$

Sara Ross

Numerade Educator

Problem 96

Describe a hydrogen bond. What conditions must exist for a hydrogen bond to form? (Chapter 12$)$

Ly Tran

Numerade Educator

Problem 97

What gas law is exemplified in Figure 17.257 State the law. (Chapter 13$)$

Sara Ross

Numerade Educator

Problem 98

When you reverse a thermochemical equation, why must you change the sign of $\Delta H ?$ (Chapter 15$)$

Ly Tran

Numerade Educator

Problem 99

What is the sign of the free energy change, $\Delta G^{\circ}$ system, for a spontaneous reaction? (Chapter 15$)$

Sara Ross

Numerade Educator

Problem 100

A New Compound Imagine that you are a scientist who has created a unique new liquid. You have named the liquid yollane, abbreviated yo. Yollane is nontoxic, inexpensive to make, and can dissolve huge volumes of gaseous carbon dioxide in the equilibrium $\mathrm{CO}_{2}(\mathrm{g}) \rightleftharpoons \mathrm{CO}_{2}(\mathrm{yo}), K_{\mathrm{eq}}=3.4 \times 10^{6} .$ Write a newspaper or magazine article that explains the merits of yollane in combating global warming.

David Collins

Numerade Educator

Problem 101

Kidney Stones Research the role that solubility plays in the formation of kidney stones. Find out what compounds are found in kidney stones and their $K_{\mathrm{sp}}$ values. Summarize your findings in a health information flyer.

Lottie Adams

Numerade Educator

Problem 102

Hard Water The presence of magnesium and calcium ions in water makes the water "hard." Explain in terms of solubility why the presence of these ions is often undesirable. Find out what measures can be taken to eliminate them.

Lottie Adams

Numerade Educator

Problem 103

Write the equilibrium constant expression for this equilibrium.

Sara Ross

Numerade Educator

Problem 104

Examine the relationship between $K_{\mathrm{eq}}$ and temperature. Use Le Chatelier's principle to deduce whether the forward reaction is exothermic or endothermic.

Ly Tran

Numerade Educator

Problem 105

Explain how automobile radiators plated with the alloy might help reduce the atmospheric concentrations of NO and CO.

Sara Ross

Numerade Educator