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Chemistry Principles and Reactions

William L. Masterton, Cecile N. Hurley

Chapter 12

Gaseous Chemical Equilibrium - all with Video Answers

Educators


Chapter Questions

01:51

Problem 1

The following data are for the system
$$
\mathrm{A}(g) \rightleftharpoons 2 \mathrm{~B}(g)
$$
$$
\begin{array}{lcccccc}
\hline \text { Time (s) } & 0 & 20 & 40 & 60 & 80 & 100 \\
P_{\mathrm{A}}(\text { atm }) & 1.00 & 0.83 & 0.72 & 0.65 & 0.62 & 0.62 \\
P_{\text {B }} \text { (atm) } & 0.00 & 0.34 & 0.56 & 0.70 & 0.76 & 0.76 \\
\hline
\end{array}
$$
(a) How long does it take the system to reach equilibrium?
(b) How does the rate of the forward reaction compare with the rate of the reverse reaction after $30 \mathrm{~s}$ ? After $90 \mathrm{~s}$ ?

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01:36

Problem 2

The following data are for the system
$$
\mathrm{A}(g) \rightleftharpoons 2 \mathrm{~B}(g)
$$
$$
\begin{array}{lcccccc}
\hline \text { Time (s) } & 0 & 30 & 45 & 60 & 75 & 90 \\
P_{\mathrm{A}} \text { (atm) } & 0.500 & 0.390 & 0.360 & 0.340 & 0.325 & 0.325 \\
P_{\text {B }} \text { (atm) } & 0.000 & 0.220 & 0.280 & 0.320 & 0.350 & 0.350 \\
\hline
\end{array}
$$
(a) How long does it take the system to reach equilibrium?
(b) How does the rate of the forward reaction compare with the rate of the reverse reaction after $45 \mathrm{~s}$ ? After $90 \mathrm{~s}$ ?

Eileen Sullivan
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03:24

Problem 3

Complete the table below for the reaction
$$
\begin{array}{c}
2 \mathrm{~A}(g)+\mathrm{B}(g) \longrightarrow 3 \mathrm{C}(g) \\
\mathrm{A}+\mathrm{B} \longrightarrow \text { products }
\end{array}
$$

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03:23

Problem 4

Complete the table below for the reaction:
$$
3 \mathrm{~A}(g)+\mathrm{B}(g) \rightleftharpoons 2 \mathrm{C}(g)
$$

Eileen Sullivan
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02:03

Problem 5

Write the equilibrium expressions $(K)$ for the following reactions:
(a) $\mathrm{CH}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{CO}(g)+3 \mathrm{H}_{2}(g)$
(b) $4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g) \rightleftharpoons 4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(g)$
(c) $\mathrm{BaCO}_{3}(s) \rightleftharpoons \mathrm{BaO}(s)+\mathrm{CO}_{2}(g)$
(d) $\mathrm{NH}_{3}(g)+\mathrm{HCl}(g) \rightleftharpoons \mathrm{NH}_{4} \mathrm{Cl}(s)$

Eileen Sullivan
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01:51

Problem 6

Write equilibrium constant $(K)$ expressions for the following reactions:
(a) $\mathrm{Na}_{2} \mathrm{CO}_{3}(s) \rightleftharpoons 2 \mathrm{NaO}(s)+\mathrm{CO}_{2}(g)$
(b) $\mathrm{C}_{2} \mathrm{H}_{6}(g)+2 \mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons 2 \mathrm{CO}(g)+5 \mathrm{H}_{2}(g)$
(c) $4 \mathrm{NO}(g)+6 \mathrm{H}_{2} \mathrm{O}(g) \rightleftharpoons 4 \mathrm{NH}_{3}(g)+5 \mathrm{O}_{2}(g)$
(d) $\mathrm{NH}_{3}(g)+\mathrm{HI}(l) \rightleftharpoons \mathrm{NH}_{4} \mathrm{I}(s)$

Eileen Sullivan
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01:54

Problem 7

Write equilibrium constant expressions $(K)$ for the following reactions:
(a) $2 \mathrm{NO}_{3}^{-}(a q)+8 \mathrm{H}^{+}(a q)+3 \mathrm{Cu}(s) \rightleftharpoons$
$$
\begin{array}{l}
\text { (b) } 2 \mathrm{PbS}(s)+3 \mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)+3 \mathrm{Cu}^{2+}(a q)+4 \mathrm{H}_{2} \mathrm{O}(l) \\
\text { (c) } \mathrm{Ca}^{2+}(a q)+\mathrm{CO}_{3}^{2-}(a q) \rightleftharpoons \mathrm{CaCO}_{3}(s)
\end{array}
$$

Eileen Sullivan
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02:06

Problem 8

Write equilibrium constant $(K)$ expressions for the following reactions:
(a) $\mathrm{I}_{2}(s)+2 \mathrm{Cl}^{-}(g) \rightleftharpoons \mathrm{Cl}_{2}(g)+2 \mathrm{I}^{-}(a q)$
(b) $\mathrm{CH}_{3} \mathrm{NH}_{2}(a q)+\mathrm{H}^{+}(a q) \rightleftharpoons \mathrm{CH}_{3} \mathrm{NH}_{3}^{+}(a q)$
(c) $\mathrm{Au}^{2+}(a q)+4 \mathrm{CN}^{-}(a q) \rightleftharpoons \mathrm{Au}(\mathrm{CN})_{4}^{2-}(a q)$

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02:28

Problem 9

Given the following descriptions of reversible reactions, write a balanced equation (smallest whole-number coefficients) and the equilibrium constant expression for each.
(a) Nickel metal reacts with carbon monoxide to form nickel tetracarbonyl $\left(\mathrm{Ni}(\mathrm{CO})_{4}\right)$ gas.
(b) Aqueous nitrous acid in equilibrium with hydrogen and nitrite ions.
(c) Chlorine gas and bromide ions in equilibrium with liquid bromine and chloride ions.

Eileen Sullivan
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02:32

Problem 10

Given the following descriptions of reversible reactions, write a balanced net ionic equation (simplest whole-number coefficients) and the equilibrium constant expression $(K)$ for each.
(a) Liquid acetone $\left(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}\right)$ is in equilibrium with its vapor.
(b) Hydrogen gas reduces nitrogen dioxide gas to form ammonia and steam.
(c) Hydrogen sulfide gas $\left(\mathrm{H}_{2} \mathrm{~S}\right)$ bubbled into an aqueous solution of lead(II) ions produces lead sulfide precipitate and hydrogen ions.

Eileen Sullivan
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01:57

Problem 11

Write an equation for an equilibrium system that would lead to the following expressions $(\mathrm{a}-\mathrm{c})$ for $\mathrm{K}$.
(a) $K=\frac{\left(P_{\mathrm{CO}}\right)^{2}\left(P_{\mathrm{H}_{2}}\right)^{5}}{\left(P_{\mathrm{C}_{2} \mathrm{H}_{6}}\right)\left(P_{\mathrm{H}_{2} \mathrm{O}}\right)^{2}}$
(b) $K=\frac{\left(P_{\mathrm{NH}}\right)^{4}\left(P_{\mathrm{O}_{2}}\right)^{5}}{\left(P_{\mathrm{NO}}\right)^{4}\left(P_{\mathrm{H}_{2} \mathrm{O}}\right)^{6}}$
(c) $K=\frac{\left[\mathrm{ClO}_{3}^{-}\right]^{2}\left[\mathrm{Mn}^{2+}\right]^{2}}{\left(P_{\mathrm{Cl}_{2}}\right)\left[\mathrm{MnO}_{4}^{-}\right]^{2}\left[\mathrm{H}^{+}\right]^{4}} ;$ liquid water is a product

Eileen Sullivan
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02:33

Problem 12

Write a chemical equation for an equilibrium system that would lead to the following expressions $(\mathrm{a}-\mathrm{d})$ for $K$.
(a) $K=\frac{\left(P_{\mathrm{H}_{2} \mathrm{~S}}\right)^{2}\left(P_{\mathrm{O}_{2}}\right)^{3}}{\left(P_{\mathrm{SO}_{2}}\right)^{2}\left(P_{\mathrm{H}_{2} \mathrm{O}}\right)^{2}}$
(b) $K=\frac{\left(P_{\mathrm{F}_{2}}\right)^{1 / 2}\left(P_{\mathrm{I}_{2}}\right)^{1 / 2}}{P_{\mathrm{IF}}}$
(c) $K=\frac{\left[\mathrm{Cl}^{-}\right]^{2}}{\left(P_{\mathrm{Cl}_{2}}\right)\left[\mathrm{Br}^{-}\right]^{2}}$
(d) $K=\frac{\left(P_{\mathrm{NO}}\right)^{2}\left(P_{\mathrm{H}_{2} \mathrm{O}}\right)^{4}\left[\mathrm{Cu}^{2+}\right]^{3}}{\left[\mathrm{NO}_{3}^{-}\right]^{2}\left[\mathrm{H}^{+}\right]^{8}}$

Eileen Sullivan
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01:44

Problem 13

Consider the following reaction at $250^{\circ} \mathrm{C}$ :
$$
\mathrm{A}(s)+2 \mathrm{~B}(g) \rightleftharpoons \mathrm{C}(s)+2 \mathrm{D}(g)
$$
(a) Write an equilibrium constant expression for the reaction. Call the equilibrium constant $K_{1}$.
(b) Write an equilibrium constant expression for the formation of one mole of $\mathrm{B}(g)$ and call the equilibrium constant $K_{2}$
(c) Relate $K_{1}$ and $K_{2}$.

Eileen Sullivan
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02:02

Problem 14

Consider the following reaction at $100^{\circ} \mathrm{C}$ :
$$
\mathrm{NO}(g)+\frac{1}{2} \mathrm{Cl}_{2}(g) \rightleftharpoons \mathrm{NOCl}(g)
$$
(a) Write an equilibrium constant expression for the reaction and call it $K^{\prime}$.
(b) Write an equilibrium constant expression for the decomposition of $\mathrm{NOCl}$ to produce one mole of chlorine gas. Call the constant $K^{\prime \prime}$.
(c) Relate $K^{\prime}$ and $K^{\prime \prime}$.

Eileen Sullivan
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01:30

Problem 15

At $627^{\circ} \mathrm{C}, K=0.76$ for the reaction
$$
2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{SO}_{3}(g)
$$
Calculate $K$ at $627^{\circ} \mathrm{C}$ for
(a) the synthesis of one mole of sulfur trioxide gas.
(b) the decomposition of two moles of $\mathrm{SO}_{3}$.

Eileen Sullivan
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01:46

Problem 16

At $800^{\circ} \mathrm{C}, K=2.2 \times 10^{-4}$ for the following reaction
$$
2 \mathrm{H}_{2} \mathrm{~S}(g) \rightleftharpoons 2 \mathrm{H}_{2}(g)+\mathrm{S}_{2}(g)
$$
Calculate $K$ at $800^{\circ} \mathrm{C}$ for
(a) the synthesis of one mole of $\mathrm{H}_{2} \mathrm{~S}$ from $\mathrm{H}_{2}$ and $\mathrm{S}_{2}$ gases.
(b) the decomposition of one mole of $\mathrm{H}_{2} \mathrm{~S}$ gas.

Eileen Sullivan
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01:56

Problem 17

Given the following reactions and their equilibrium constants,
$$
\begin{aligned}
\mathrm{H}_{2} \mathrm{O}(g)+\mathrm{CO}(g) & \rightleftharpoons \mathrm{H}_{2}(g)+\mathrm{CO}_{2}(g) & & K=1.6 \\
\mathrm{FeO}(s)+\mathrm{CO}(g) & \rightleftharpoons \mathrm{Fe}(s)+\mathrm{CO}_{2}(g) & & K=0.67
\end{aligned}
$$
calculate $K$ for the reaction
$$
\mathrm{Fe}(s)+\mathrm{H}_{2} \mathrm{O}(g) \rightleftharpoons \mathrm{FeO}(s)+\mathrm{H}_{2}(g)
$$

Eileen Sullivan
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02:38

Problem 18

Given the following data at $25^{\circ} \mathrm{C}$
$$
\begin{array}{ll}
2 \mathrm{NO}(g) \rightleftharpoons \mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) & K=1 \times 10^{-30} \\
2 \mathrm{NO}(g)+\mathrm{Br}_{2}(g) \rightleftharpoons 2 \mathrm{NOBr}(g) & K=8 \times 10^{1}
\end{array}
$$
Calculate $K$ for the formation of one mole of NOBr from its elements in the gaseous state.

Eileen Sullivan
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03:02

Problem 19

Given the following data at a certain temperature,
$$
\begin{array}{cl}
2 \mathrm{~N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{~N}_{2} \mathrm{O}(g) & K=1.2 \times 10^{-35} \\
\mathrm{~N}_{2} \mathrm{O}_{4}(g) \rightleftharpoons 2 \mathrm{NO}_{2}(g) & K=4.6 \times 10^{-3} \\
\frac{1}{2} \mathrm{~N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons \mathrm{NO}_{2}(g) & K=4.1 \times 10^{-9}
\end{array}
$$
calculate $K$ for the reaction between one mole of dinitrogen oxide gas and oxygen gas to give dinitrogen tetroxide gas.

Eileen Sullivan
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02:02

Problem 20

Consider the following hypothetical reactions and their equilibrium constants at $75^{\circ} \mathrm{C}$
$$
\begin{array}{ll}
3 \mathrm{~A}(g) \rightleftharpoons 3 \mathrm{~B}(g)+2 \mathrm{C}(g) & K_{1}=0.31 \\
3 \mathrm{D}(g)+2 \mathrm{~B}(g) \rightleftharpoons 2 \mathrm{C}(g) & K_{2}=2.8
\end{array}
$$
Find the equilibrium constant at $75^{\circ} \mathrm{C}$ for the following reaction
$$
\mathrm{A}(g) \rightleftharpoons \mathrm{D}(g)+\frac{5}{3} \mathrm{~B}(g)
$$

Eileen Sullivan
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01:34

Problem 21

When one mole of carbon disulfide gas reacts with hydrogen gas, methane and hydrogen sulfide gases are formed. When equilibrium is reached at $900^{\circ} \mathrm{C}$, analysis shows that $P_{\mathrm{CH}_{4}}=0.0833 \mathrm{~atm}, P_{\mathrm{H}_{2} \mathrm{~s}}=0.163 \mathrm{~atm}, P_{\mathrm{CS}_{2}}=$
$1.27 \mathrm{~atm},$ and $P_{\mathrm{H}_{2}}=0.873 \mathrm{~atm}$
(a) Write a balanced equation (smallest whole-number coefficients) for the reaction.
(b) Find $K$ at $900^{\circ} \mathrm{C}$.

Eileen Sullivan
Eileen Sullivan
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01:03

Problem 22

Calculate $K$ for the formation of methyl alcohol at $100^{\circ} \mathrm{C}$ :
$$
\mathrm{CO}(g)+2 \mathrm{H}_{2}(g) \rightleftharpoons \mathrm{CH}_{3} \mathrm{OH}(g)
$$
given that at equilibrium, the partial pressures of the gases
$$
\text { are } P_{\mathrm{CO}}=0.814 \mathrm{~atm}, \quad P_{\mathrm{H}_{2}}=0.274 \mathrm{~atm}, \text { and } P_{\mathrm{CH}_{3} \mathrm{OH}}=
$$
$0.0512 \mathrm{~atm} .$

Eileen Sullivan
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01:15

Problem 23

Ammonium carbamate solid $\left(\mathrm{NH}_{4} \mathrm{CO}_{2} \mathrm{NH}_{2}\right)$ decomposes at $313 \mathrm{~K}$ into ammonia and carbon dioxide gases. At equilibrium, analysis shows that there are $0.0451 \mathrm{~atm}$ of $\mathrm{CO}_{2}$, 0.0961 atm of ammonia, and $0.159 \mathrm{~g}$ of ammonium carbamate.
(a) Write a balanced equation for the decomposition of one mole of $\mathrm{NH}_{4} \mathrm{CO}_{2} \mathrm{NH}_{2}$.
(b) Calculate $K$ at $313 \mathrm{~K}$.

Eileen Sullivan
Eileen Sullivan
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02:49

Problem 24

Consider the decomposition at $25^{\circ} \mathrm{C}$ of one mole of NOBr gas into $\mathrm{NO}$ and $\mathrm{Br}_{2}$ gases. At equilibrium, the concentrations of $\mathrm{NOBr}, \mathrm{NO},$ and $\mathrm{Br}_{2}$ gases are $0.0162 \mathrm{M}$, $0.0011 \mathrm{M},$ and $0.072 \mathrm{M},$ respectively.
(a) Write a balanced equation for the reaction.
(b) Calculate $K$ for the reaction at $25^{\circ} \mathrm{C}$. (Note that the gases need to be expressed as pressure in atm.)

Eileen Sullivan
Eileen Sullivan
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01:51

Problem 25

Consider the decomposition of ammonium hydrogen sulfide:
$$
\mathrm{NH}_{4} \mathrm{HS}(s) \rightleftharpoons \mathrm{NH}_{3}(g)+\mathrm{H}_{2} \mathrm{~S}(g)
$$
In a sealed flask at $25^{\circ} \mathrm{C}$ are $10.0 \mathrm{~g}$ of $\mathrm{NH}_{4} \mathrm{HS}$, ammonia with a partial pressure of $0.692 \mathrm{~atm},$ and $\mathrm{H}_{2} \mathrm{~S}$ with a partial pressure of $0.0532 \mathrm{~atm}$. When equilibrium is established, it is found that the partial pressure of ammonia has increased by 12.4\%. Calculate $K$ for the decomposition of $\mathrm{NH}_{4} \mathrm{HS}$ at $25^{\circ} \mathrm{C}$.

Eileen Sullivan
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01:59

Problem 26

A sealed flask has $0.541 \mathrm{~atm}$ of $\mathrm{SO}_{3}$ at $1000 \mathrm{~K}$. The following equilibrium is established.
$$
2 \mathrm{SO}_{3}(g) \rightleftharpoons 2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g)
$$
At equilibrium, the partial pressure of oxygen is measured to be 0.216 atm. Calculate $K$ for the decomposition of $\mathrm{SO}_{3}$ at $1000 \mathrm{~K}$

Eileen Sullivan
Eileen Sullivan
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01:59

Problem 27

A gaseous reaction mixture contains $0.30 \mathrm{~atm} \mathrm{SO}_{2}$, $0.16 \mathrm{~atm} \mathrm{Cl}_{2},$ and $0.50 \mathrm{~atm} \mathrm{SO}_{2} \mathrm{Cl}_{2}$ in a $2.0-\mathrm{L}$ container.
$K=0.011$ for the equilibrium system
$$
\mathrm{SO}_{2} \mathrm{Cl}_{2}(g) \rightleftharpoons \mathrm{SO}_{2}(g)+\mathrm{Cl}_{2}(g)
$$
(a) Is the system at equilibrium? Explain.
(b) If it is not at equilibrium, in which direction will the system move to reach equilibrium?

Eileen Sullivan
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02:07

Problem 28

For the system
$$
\mathrm{PCl}_{5}(g) \rightleftharpoons \mathrm{PCl}_{3}(g)+\mathrm{Cl}_{2}(g)
$$
$K$ is 26 at $300^{\circ} \mathrm{C}$. In a $10.0-\mathrm{L}$ flask at $300^{\circ} \mathrm{C}$, a gaseous mixture consists of all three gases with the following partial pres-
$$
\text { sures: } P_{\mathrm{PCl}_{5}}=0.026 \mathrm{~atm}, P_{\mathrm{PCl}_{3}}=0.65 \mathrm{~atm}, P_{\mathrm{Cl}_{2}}=0.33 \mathrm{~atm}
$$
(a) Is the system at equilibrium? Explain.
(b) If the system is not at equilibrium, in which direction will the system move to reach equilibrium?

Eileen Sullivan
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02:30

Problem 29

The reversible reaction between hydrogen chloride gas and one mole of oxygen gas produces steam and chlorine gas:
$$
4 \mathrm{HCl}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{Cl}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(g) \quad K=0.79
$$
Predict the direction in which the system will move to reach equilibrium if one starts with
$$
\text { (a) } P_{\mathrm{H}_{2} \mathrm{O}}=P_{\mathrm{HCl}}=P_{\mathrm{O}_{2}}=0.20 \mathrm{~atm}
$$
(b) $P_{\mathrm{HCl}}=0.30 \mathrm{~atm}, P_{\mathrm{H}_{2} \mathrm{O}}=0.35 \mathrm{~atm}, P_{\mathrm{Cl}_{2}}=0.2 \mathrm{~atm}$
$P_{\mathrm{O}_{2}}=0.15 \mathrm{~atm}$

Eileen Sullivan
Eileen Sullivan
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02:52

Problem 30

For the reaction
$$
\mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{NH}_{3}(g)
$$
$K$ at a certain temperature is $3.7 \times 10^{-4}$. Predict the direction in which the system will move to reach equilibrium if one starts with
$$
\begin{array}{l}
\text { (a) } P_{\mathrm{N}_{2}}=P_{\mathrm{H}_{2}}=P_{\mathrm{NH}_{3}}=0.01 \mathrm{~atm} \\
\text { (b) } P_{\mathrm{NH}_{3}}=0.0045 \mathrm{~atm}
\end{array}
$$
(c) $P_{\mathrm{N}_{2}}=1.2 \mathrm{~atm}, P_{\mathrm{H}_{2}}=1.88 \mathrm{~atm}, P_{\mathrm{NH}_{3}}=0.0058 \mathrm{~atm}$

Eileen Sullivan
Eileen Sullivan
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01:52

Problem 31

A compound, X, decomposes at $131^{\circ} \mathrm{C}$ according to the following equation:
$$
2 \mathrm{X}(g) \rightleftharpoons \mathrm{A}(g)+3 \mathrm{C}(g) \quad K=1.1 \times 10^{-3}
$$
If a flask initially contains $\mathrm{X}, \mathrm{A},$ and $\mathrm{C},$ all at partial pressures of $0.250 \mathrm{~atm}$, in which direction will the reaction proceed?

Eileen Sullivan
Eileen Sullivan
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01:53

Problem 32

Consider the following reaction at $75^{\circ} \mathrm{C}$ :
$$
3 \mathrm{R}(s)+2 \mathrm{Q}(g) \rightleftharpoons \mathrm{A}(g)+5 \mathrm{~B}(l) \quad K=9.4
$$
A $10.0-\mathrm{L}$ sample contains $0.30 \mathrm{~mol}$ of $\mathrm{R}$ and $\mathrm{Q}$ and $0.50 \mathrm{~mol}$ of $\mathrm{A}$ and $\mathrm{B}$. In which direction will the reaction proceed?

Eileen Sullivan
Eileen Sullivan
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02:01

Problem 33

Consider the reaction between nitrogen and steam:
$$
2 \mathrm{~N}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(g) \rightleftharpoons 4 \mathrm{NH}_{3}(g)+3 \mathrm{O}_{2}(g)
$$
At a certain temperature, $K=28.6 .$ Calculate the equilibrium partial pressure of steam if $P_{\mathrm{NH}_{3}}=1.75$ atm, $P_{\mathrm{O}_{2}}=0.963 \mathrm{~atm},$ and $P_{\mathrm{N}_{2}}=0.996$ atm at equilibrium.

Eileen Sullivan
Eileen Sullivan
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01:27

Problem 34

At $500^{\circ} \mathrm{C}, K$ for the formation of ammonia from nitrogen and hydrogen gases is $1.5 \times 10^{-5}$.
$$
\mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{NH}_{3}(g)
$$
Calculate the equilibrium partial pressure of hydrogen if the equilibrium partial pressures of ammonia and nitrogen are $0.015 \mathrm{~atm}$ and $1.2 \mathrm{~atm}$, respectively.
35. At a certain temperature, $K$ is 4.9 for the formation of one mole of bromine chloride gas (BrCl) from its elements. A mixture at equilibrium at this temperature contains all three gases. The partial pressures at equilibrium of bromine and chlorine gas is $0.19 \mathrm{~atm}$. What is the partial pressure of bromine chloride in this mixture at equilibrium?

Eileen Sullivan
Eileen Sullivan
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01:32

Problem 35

At a certain temperature, $K$ is 4.9 for the formation of one mole of bromine chloride gas (BrCl) from its elements. A mixture at equilibrium at this temperature contains all three gases. The partial pressures at equilibrium of bromine and chlorine gas is 0.19 atm. What is the partial pressure of bromine chloride in this mixture at equilibrium?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:51

Problem 36

At a certain temperature, $K=0.29$ for the decomposition of two moles of iodine trichloride, $\mathrm{ICl}_{3}(s),$ to chlorine and iodine gases. The partial pressure of chlorine gas at equilibrium is three times that of iodine gas. What are the partial pressures of iodine and chlorine at equilibrium?

Eileen Sullivan
Eileen Sullivan
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08:31

Problem 37

For the reaction
$$
\mathrm{N}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(g) \rightleftharpoons 2 \mathrm{NO}(g)+2 \mathrm{H}_{2}(g)
$$
$K$ is $1.54 \times 10^{-3}$. When equilibrium is established, the partial pressure of nitrogen is $0.168 \mathrm{~atm}$, and that of $\mathrm{NO}$ is 0.225 atm. The total pressure of the system at equilibrium is 1.87 atm. What are the equilibrium partial pressures of hydrogen and steam?

Susan Hallstrom
Susan Hallstrom
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03:37

Problem 38

Nitrogen dioxide can decompose to nitrogen oxide and oxygen.
$$
2 \mathrm{NO}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)+\mathrm{O}_{2}(g)
$$
$K$ is 0.87 at a certain temperature. A $5.0-\mathrm{L}$ flask at equilibrium is determined to have a total pressure of 1.25 atm and oxygen to have a partial pressure of 0.515 atm. Calculate $P_{\mathrm{NO}}$ and $P_{\mathrm{NO}_{2}}$ at equilibrium.

Eileen Sullivan
Eileen Sullivan
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04:21

Problem 39

Consider the following reaction:
$$
\mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)
$$
At a certain temperature, the equilibrium constant for the reaction is $0.0639 .$ What are the partial pressures of all gases at equilibrium if the initial partial pressure of the gases (both products and reactants) is $0.400 \mathrm{~atm} ?$

Eileen Sullivan
Eileen Sullivan
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03:36

Problem 40

Consider the hypothetical reaction at $325^{\circ} \mathrm{C}$
$$
\mathrm{R}(g)+\mathrm{Q}(g) \rightleftharpoons 2 \mathrm{Z}(g) \quad K=2.71
$$
What are the equilibrium partial pressures of all the gases if all the gases (products and reactants) have an initial partial pressure of 0.228 atm?

Eileen Sullivan
Eileen Sullivan
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05:45

Problem 41

At a certain temperature, the equilibrium constant for the following reaction is 0.0472 .
$$
\mathrm{NO}(g)+\mathrm{SO}_{3}(g) \rightleftharpoons \mathrm{SO}_{2}(g)+\mathrm{NO}_{2}(g)
$$
All gases are at an initial pressure of $0.862 \mathrm{~atm} .$
(a) Calculate the partial pressure of each gas at equilibrium.
(b) Compare the initial total pressure with the total pressure of the gases at equilibrium. Would that relation be true of all gaseous systems?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:53

Problem 42

At $460^{\circ} \mathrm{C}$, the reaction
$$
\mathrm{SO}_{2}(g)+\mathrm{NO}_{2}(g) \rightleftharpoons \mathrm{NO}(g)+\mathrm{SO}_{3}(g)
$$
has $K=84.7$. All gases are at an initial pressure of 1.25 atm.
(a) Calculate the partial pressure of each gas at equilibrium.
(b) Compare the total pressure initially with the total pressure at equilibrium. Would that relation be true of all gaseous systems?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:39

Problem 43

Solid ammonium iodide decomposes to ammonia and hydrogen gases at sufficiently high temperatures.
$$
\mathrm{NH}_{4} \mathrm{I}(s) \rightleftharpoons \mathrm{NH}_{3}(g)+\mathrm{HI}(g)
$$
The equilibrium constant for the decomposition at $400^{\circ} \mathrm{C}$ is 0.215. Twenty grams of ammonium iodide are sealed in a $7.50-\mathrm{L}$ flask and heated to $400^{\circ} \mathrm{C}$.
(a) What is the total pressure in the flask at equilibrium?
(b) How much solid $\mathrm{NH}_{4} \mathrm{I}$ is left after the decomposition?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:01

Problem 44

Consider the following decomposition at $80^{\circ} \mathrm{C}$.
$\mathrm{PH}_{3} \mathrm{BCl}_{3}(s) \rightleftharpoons \mathrm{PH}_{3}(g)+\mathrm{BCl}_{3}(g) \quad K=0.054$
Twenty grams of $\mathrm{PH}_{3} \mathrm{BCl}_{3}$ are sealed in a $5.0-\mathrm{L}$ flask and heated to $80^{\circ} \mathrm{C}$
(a) What is the total pressure in the flask at equilibrium?
(b) How many grams of $\mathrm{PH}_{3} \mathrm{BCl}_{3}$ are left in the flask at equilibrium?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:15

Problem 45

Hydrogen cyanide, a highly toxic gas, can decompose to cyanogen and hydrogen gases,
$$
2 \mathrm{HCN}(g) \rightleftharpoons \mathrm{C}_{2} \mathrm{~N}_{2}(g)+\mathrm{H}_{2}(g)
$$
At a certain temperature, $K$ for this decomposition is 0.17 . What are the partial pressures of all gases at equilibrium if initially the partial pressures are $P_{\mathrm{C}_{2} \mathrm{~N}_{2}}=P_{\mathrm{H}_{2}}=0.32 \mathrm{~atm}$
$P_{\mathrm{HCN}}=0.45 \mathrm{~atm} ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:25

Problem 46

At $800 \mathrm{~K}$, hydrogen iodide can decompose into hydrogen and iodine gases.
$$
2 \mathrm{HI}(g) \rightleftharpoons \mathrm{I}_{2}(g)+\mathrm{H}_{2}(g)
$$
At this temperature, $K=0.0169 .$ What are the partial pressures at equilibrium of the hydrogen and iodine if initially a sealed flask at $800 \mathrm{~K}$ contains only HI at a pressure of 0.200 atm?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:04

Problem 47

For the following reactions, predict whether the pressure of the reactants or products increases or remains the same when the volume of the reaction vessel is increased.
(a) $\mathrm{H}_{2} \mathrm{O}(l) \rightleftharpoons \mathrm{H}_{2} \mathrm{O}(g)$
(b) $\mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{NH}_{3}(g)$
(c) $\mathrm{C}_{2} \mathrm{H}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g) \rightleftharpoons \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(g)$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:59

Problem 48

Follow the directions of Question 47 for the following reactions:
(a) $2 \mathrm{H}_{2} \mathrm{O}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{H}_{2} \mathrm{O}_{2}(g)$
(b) $2 \mathrm{CH}_{4}(g) \rightleftharpoons \mathrm{C}_{2} \mathrm{H}_{2}(g)+3 \mathrm{H}_{2}(g)$
(c) $\mathrm{Br}_{2}(g)+\mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{HBr}(g)$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:38

Problem 49

Consider the system
$$
\mathrm{SO}_{3}(g) \rightleftharpoons \mathrm{SO}_{2}(g)+\frac{1}{2} \mathrm{O}_{2}(g) \quad \Delta H=98.9 \mathrm{~kJ}
$$
(a) Predict whether the forward or reverse reaction will occur when the equilibrium is disturbed by
1. adding oxygen gas.
2. compressing the system at constant temperature.
3. adding argon gas.
4. removing $\mathrm{SO}_{2}(g)$.
5. decreasing the temperature.
(b) Which of the above factors will increase the value of K? Which will decrease it?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:26

Problem 50

Consider the system
$4 \mathrm{NH}_{3}(g)+3 \mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{~N}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(l) \quad \Delta H=-1530.4 \mathrm{~kJ}$
(a) How will the amount of ammonia at equilibrium be affected by
1. removing $\mathrm{O}_{2}(g) ?$
2. adding $\mathrm{N}_{2}(g) ?$
3. adding water?
4. expanding the container at constant pressure?
5. increasing the temperature?
(b) Which of the above factors will increase the value of $K ?$ Which will decrease it?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:44

Problem 51

Predict the direction in which each of the following equilibria will shift if the pressure on the system is decreased by expansion.
(a) $\mathrm{Ni}(s)+4 \mathrm{CO}(g) \rightleftharpoons \mathrm{Ni}(\mathrm{CO})_{4}(g)$
(b) $2 \mathrm{CH}_{4}(g) \rightleftharpoons \mathrm{C}_{2} \mathrm{H}_{2}(g)+3 \mathrm{H}_{2}(g)$
(c) $\mathrm{Br}_{2}(g)+\mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{HBr}(g)$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:47

Problem 52

Predict the direction in which each of the following equilibria will shift if the pressure on the system is decreased by expansion.
(a) $2 \mathrm{H}_{2} \mathrm{O}_{2}(l) \rightleftharpoons \mathrm{O}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(l)$
(b) $2 \mathrm{CH}_{4}(g) \rightleftharpoons \mathrm{C}_{2} \mathrm{H}_{2}(g)+3 \mathrm{H}_{2}(g)$
(c) $\mathrm{I}_{2}(s)+\mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{HI}(g)$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:20

Problem 53

At a certain temperature, nitrogen and oxygen gases combine to form nitrogen oxide gas.
$$
\mathrm{N}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}(g)
$$
When equilibrium is established, the partial pressures of the gases
$$
\text { are: } P_{\mathrm{N}_{2}}=1.200 \mathrm{~atm}, P_{\mathrm{O}_{2}}=0.800 \mathrm{~atm}, P_{\mathrm{NO}}=0.0220 \mathrm{~atm} .
$$
(a) Calculate $K$ at the temperature of the reaction.
(b) After equilibrium is reached, more oxygen is added to make its partial pressure 1.200 atm. Calculate the partial pressure of all gases when equilibrium is reestablished.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:35

Problem 54

Consider the following hypothetical reaction:
$$
\mathrm{X}_{2}(g)+\mathrm{R}(s) \rightleftharpoons \mathrm{X}_{2} \mathrm{R}(g)
$$
$\mathrm{R}$ has a molar mass of $73 \mathrm{~g} / \mathrm{mol}$. When equilibrium is established, a 2.5-L reaction vessel at $125^{\circ} \mathrm{C}$ contains $15.0 \mathrm{~g}$ of $\mathrm{R}$,
4.3 atm of $\mathrm{X}_{2}$, and 0.98 atm of $\mathrm{X}_{2} \mathrm{R}$.
(a) Calculate $K$ for the reaction at $125^{\circ} \mathrm{C}$.
(b) The mass of $\mathrm{R}$ is doubled. What are the partial pressures of $\mathrm{X}_{2}$ and $\mathrm{X}_{2} \mathrm{R}$ when equilibrium is reestablished?
(c) The partial pressure of $\mathrm{X}_{2}$ is decreased to $2.0 \mathrm{~atm}$. What are the partial pressures of $\mathrm{X}_{2}$ and $\mathrm{X}_{2} \mathrm{R}$ when equilibrium is reestablished?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:43

Problem 55

Iodine chloride decomposes at high temperatures to iodine and chlorine gases.
$$
2 \mathrm{ICl}(g) \rightleftharpoons \mathrm{I}_{2}(g)+\mathrm{Cl}_{2}(g)
$$
Equilibrium is established at a certain temperature when the partial pressures of $\mathrm{ICl}, \mathrm{I}_{2},$ and $\mathrm{Cl}_{2}$ are (in atm) 0.43,0.16 , and $0.27,$ respectively.
(a) Calculate $K$.
(b) If enough iodine condenses to decrease its partial pressure to $0.10 \mathrm{~atm}$, in which direction will the reaction proceed? What is the partial pressure of iodine when - auilibrium is reestablis]

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:00

Problem 56

Sulfur oxychloride, $\mathrm{SO}_{2} \mathrm{Cl}_{2}$, decomposes to sulfur dioxide and chlorine gases.
$$
\mathrm{SO}_{2} \mathrm{Cl}_{2}(g) \rightleftharpoons \mathrm{SO}_{2}(g)+\mathrm{Cl}_{2}(g)
$$
At a certain temperature, the equilibrium partial pressures of $\mathrm{SO}_{2}, \mathrm{Cl}_{2},$ and $\mathrm{SO}_{2} \mathrm{Cl}_{2}$ are $1.88 \mathrm{~atm}, 0.84 \mathrm{~atm},$ and $0.27 \mathrm{~atm}$
respectively.
(a) What is $K$ at that temperature?
(b) Enough $\mathrm{Cl}_{2}$ condenses to reduce its partial pressure to 0.68 atm. What are the partial pressures of all gases when equilibrium is reestablished?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:44

Problem 57

For the following reaction
$$
\mathrm{C}(s)+2 \mathrm{H}_{2}(g) \rightleftharpoons \mathrm{CH}_{4}(g)
$$
$K=0.26$ at $1000^{\circ} \mathrm{C}$ ( 3 significant figures). What is the equilibrium constant at $750^{\circ} \mathrm{C}$ ( 3 significant figures)?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:58

Problem 58

For the system
$$
2 \mathrm{SO}_{3}(g) \rightleftharpoons 2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g)
$$
$K=1.32$ at $627^{\circ} \mathrm{C}$. What is the equilibrium constant at
$$
555^{\circ} \mathrm{C} ?
$$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:21

Problem 59

For a certain reaction, $\Delta H^{\circ}$ is $+33 \mathrm{~kJ}$. What is the ratio of the equilibrium constant at $400 \mathrm{~K}$ to that at $200 \mathrm{~K}$ ?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:40

Problem 60

What is the value of $\Delta H^{\circ}$ for a reaction in which $K$ at $37^{\circ} \mathrm{C}$ is $48 \%$ of $K$ at $27^{\circ} \mathrm{C} ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:14

Problem 61

Hemoglobin (Hb) hinds to both oxygen and carhon monoxide. When the carbon monoxide replaces the oxygen in an organism, the following reaction occurs:
$$
\mathrm{HbO}_{2}(a q)+\mathrm{CO}(g) \rightleftharpoons \mathrm{HbCO}(a q)+\mathrm{O}_{2}(g)
$$
At $37^{\circ} \mathrm{C}, K$ is about 200 . When equal concentrations of $\mathrm{HbO}_{2}$ and $\mathrm{HbCO}$ are present, the effect of CO inhalation is fatal. Assuming $\mathrm{P}_{\mathrm{O}_{2}}=0.21 \mathrm{~atm},$ what is $\mathrm{P}_{\mathrm{CO}}$ when $\left[\mathrm{HbO}_{2}\right]=$
$[\mathrm{HbCO}] ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:37

Problem 62

Mustard gas, used in chemical warfare in World War I, has been found to be an effective agent in the chemotherapy of Hodgkin's disease. It can be produced according to the following reaction:
$$
\mathrm{SCl}_{2}(g)+2 \mathrm{C}_{2} \mathrm{H}_{4}(g) \rightleftharpoons \mathrm{S}\left(\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Cl}\right)_{2}(g)
$$
An evacuated $5.0-\mathrm{L}$ flask at $20.0^{\circ} \mathrm{C}$ is filled with $0.258 \mathrm{~mol}$ $\mathrm{SCl}_{2}$ and $0.592 \mathrm{~mol} \mathrm{C}_{2} \mathrm{H}_{4}$. After equilibrium is established, 0.0349 mol mustard gas is present.
(a) What is the partial pressure of each gas at equilibrium?
(b) What is $K$ at $20.0^{\circ} \mathrm{C} ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:49

Problem 63

At $1000 \mathrm{~K}$, hydrogen dissociates into gaseous atoms:
$$
\mathrm{H}_{2}(g) \rightleftharpoons 2 \mathrm{H}(g)
$$
where $K$ is $5.0 \times 10^{-18}$. Ten moles of hydrogen gas are pumped into an evacuated $15.0-\mathrm{L}$ flask and heated to $1000 \mathrm{~K}$
(a) How many atoms of $\mathrm{H}$ are in the flask when equilibrium is reached?
(b) What percent (in moles) of $\mathrm{H}_{2}$ dissociated?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:13

Problem 64

For the decomposition of $\mathrm{CaCO}_{3}$ at $900^{\circ} \mathrm{C}, \mathrm{K}=1.04$.
$$
\mathrm{CaCO}_{3}(s) \rightleftharpoons \mathrm{CaO}(s)+\mathrm{O}_{2}(g)
$$
Find the smallest mass of $\mathrm{CaCO}_{3}$ needed to reach equilibrium in a $5.00-\mathrm{L}$ vessel at $900^{\circ} \mathrm{C}$.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:15

Problem 65

Isopropyl alcohol is the main ingredient in rubbing alcohol. It can decompose into acetone (the main ingredient in nail polish remover) and hydrogen gas according to the following reaction:
$$
\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH}(g) \rightleftharpoons \mathrm{C}_{2} \mathrm{H}_{6} \mathrm{CO}(g)+\mathrm{H}_{2}(g)
$$
At $180^{\circ} \mathrm{C}$, the equilibrium constant for the decomposition is 0.45. If $20.0 \mathrm{~mL}(d=0.785 \mathrm{~g} / \mathrm{mL})$ of isopropyl alcohol is placed in a $5.00-\mathrm{L}$ vessel and heated to $180^{\circ} \mathrm{C},$ what percentage remains undissociated at equilibrium?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:25

Problem 66

Consider the equilibrium
$$
\mathrm{H}_{2}(g)+\mathrm{S}(s) \rightleftharpoons \mathrm{H}_{2} \mathrm{~S}(g)
$$
When this system is at equilibrium at $25^{\circ} \mathrm{C}$ in a $2.00-\mathrm{L}$ container, $0.120 \mathrm{~mol}$ of $\mathrm{H}_{2}, 0.034 \mathrm{~mol}$ of $\mathrm{H}_{2} \mathrm{~S},$ and $0.4000 \mathrm{~mol}$
of $\mathrm{S}$ are present. When the temperature is increased to $35^{\circ} \mathrm{C}$, the partial pressure of $\mathrm{H}_{2}$ increases to $1.56 \mathrm{~atm} .$
(a) What is $K$ for the reaction at $25^{\circ} \mathrm{C} ?$
(b) What is $K$ for the reaction at $35^{\circ} \mathrm{C} ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:58

Problem 67

Consider the following graph representing the progression of a reaction with time.
(a) What is the relationship between $Q$ and $K$ at Points $1,3,$ and $4 ?$
(b) What caused the disturbance at Point $2 ?$
(c) Draw a similar graph for the same reaction, but increase the pressure in $\mathrm{A}$.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:39

Problem 68

The following data apply to the unbalanced equation
$$
\mathrm{A}(g) \rightleftharpoons \mathrm{B}(g)
$$
$$
\begin{array}{lcccccc}
\hline \text { Time (s) } & 0 & 50 & 100 & 150 & 200 & 250 \\
P_{\mathrm{A}}(\text { atm }) & 2.00 & 1.25 & 0.95 & 0.80 & 0.71 & 0.68 \\
P_{\mathrm{B}}(\mathrm{atm}) & 0.10 & 0.60 & 0.80 & 0.90 & 0.96 & 0.98 \\
\hline
\end{array}
$$
(a) On the basis of the data, balance the equation (simplest whole-number coefficients).
(b) Has the system reached equilibrium? Explain.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:36

Problem 69

Consider the reaction:
$$
\mathrm{A}(g)+2 \mathrm{~B}(g)+\mathrm{C}(s) \rightleftharpoons 2 \mathrm{D}(g)
$$
At $25^{\circ} \mathrm{C},$ only $\mathrm{A}, \mathrm{B},$ and $\mathrm{C}$ are present. The partial pressures of $\mathrm{A}, \mathrm{B},$ and $\mathrm{D}$ are given as $P_{\mathrm{A}}, P_{\mathrm{B}},$ and $P_{\mathrm{D}} .$ Equilibrium is established 18 minutes after the reaction starts. Use terms is less than $(\mathrm{LT})$, is greater than $(\mathrm{GT})$, is equal to $(\mathrm{EQ})$, or insufficient information $(\mathbf{X})$ to answer the following questions.
$$
\text { (a) } P_{\mathrm{D}} \text { at } 5 \mathrm{~min}=P_{\mathrm{A}} \text { . }
$$
(b) $P_{\mathrm{A}}$ at $21 \mathrm{~min}$
$P_{\mathrm{A}}$ at $27 \mathrm{~min}$
(c) $P_{\mathrm{B}}$ at $7 \mathrm{~min} \longrightarrow P_{\mathrm{B}}$ at $13 \mathrm{~min}$.
(d) After $20 \mathrm{~min},$ more $\mathrm{B}$ is added. When equilibrium is reestablished, $K$ before the addition $K$ after the addition.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:15

Problem 70

For the reaction
$$
\mathrm{C}(s)+\mathrm{CO}_{2}(g) \rightleftharpoons 2 \mathrm{CO}(g)
$$
$K=168$ at $1273 \mathrm{~K}$. If one starts with $0.3 \mathrm{~atm}$ of $\mathrm{CO}_{2}$ and
$12.0 \mathrm{~g}$ of $\mathrm{C}$ at $1273 \mathrm{~K}$, will the equilibrium mixture contain
(a) mostly $\mathrm{CO}_{2} ?$
(b) mostly CO?
(c) roughly equal amounts of $\mathrm{CO}_{2}$ and $\mathrm{CO}$ ?
(d) only C?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:42

Problem 71

Consider the system
$$
\mathrm{A}(g)+2 \mathrm{~B}(g)+\mathrm{C}(s) \rightleftharpoons 2 \mathrm{D}(g)
$$
at $25^{\circ} \mathrm{C}$. At zero time, only $\mathrm{A}, \mathrm{B},$ and $\mathrm{C}$ are present. The reaction reaches equilibrium 10 min after the reaction is initiated. Partial pressures of $\mathrm{A}, \mathrm{B},$ and $\mathrm{D}$ are written as $P_{\mathrm{A}}, P_{\mathrm{B}},$ and $P_{\mathrm{D}}$
Answer the questions below, using LT (for is less than), GT (for is greater than), EQ (for is equal to), or MI (for more information required).
(a) $P_{\mathrm{D}}$ at $11 \mathrm{~min}$
$$
P_{\mathrm{D}} \text { at } 12 \mathrm{~min}
$$
(b) $P_{\mathrm{A}}$ at $5 \mathrm{~min} \longrightarrow P_{\mathrm{A}}$ at $7 \mathrm{~min}$.
(c) $K$ for the forward reaction reaction.
(d) At equilibrium, $K \longrightarrow$
(e) After the system is at equilibrium, more of gas $\mathrm{B}$ is added. After the system returns to equilibrium, $K$ before the addition of $\mathrm{B} \longrightarrow \mathrm{K}$ after the addition of $\mathrm{B}$.
(f) The same reaction is initiated, this time with a catalyst. $K$ for the system without a catalyst $K$ for the system with a catalyst.
(g) $K$ for the formation of one mole of $\mathrm{D}$ $K$ for the formation of two moles of $\mathrm{D}$.
(h) The temperature of the system is increased to $35^{\circ} \mathrm{C} . P_{\mathrm{B}}$ at equilibrium at $25^{\circ} \mathrm{C}$ $P_{\mathrm{B}}$ at equilibrium at $35^{\circ} \mathrm{C}$.
(i) Ten more grams of $\mathrm{C}$ are added to the system. $P_{\mathrm{B}}$ before the addition of $\mathrm{C} \longrightarrow P_{\mathrm{B}}$ after the addition of $\mathrm{C}$.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:31

Problem 72

The graph below is similar to that of Figure 12.2 .
If after $100 \mathrm{~s}$ have elapsed the partial pressure of $\mathrm{N}_{2} \mathrm{O}_{4}$ is increased to $1.0 \mathrm{~atm},$ what will the graph for $\mathrm{N}_{2} \mathrm{O}_{4}$ look like beyond $100 \mathrm{~s}$ ?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:08

Problem 73

The system
$$
3 Z(g)+\mathrm{Q}(g) \rightleftharpoons 2 \mathrm{R}(g)
$$
is at equilibrium when the partial pressure of $\mathrm{Q}$ is $0.44 \mathrm{~atm}$. Sufficient $\mathrm{R}$ is added to increase the partial pressure of $\mathrm{Q}$ temporarily to 1.5 atm. When equilibrium is reestablished, the partial pressure of $\mathrm{Q}$ could be which of the following?
(a) 1.5 atm
(b) 1.2 atm
(c) 0.80 atm
(d) $0.44 \mathrm{~atm}$
(e) $0.40 \mathrm{~atm}$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:18

Problem 74

The figures below represent the following reaction at equilibrium at different temperatures.
$$
\mathrm{A}_{2}(g)+3 \mathrm{~B}_{2}(g) \rightleftharpoons 2 \mathrm{AB}_{3}(g)
$$
where squares represent atom A and circles represent atom B. Is the reaction exothermic?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:54

Problem 75

Criticize the statement "The rate of most reactions increases as the temperature rises. Thus, the equilibrium constant of most reactions increases as temperature rises."

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:23

Problem 76

Consider the statement "The equilibrium constant for a mixture of hydrogen, nitrogen, and ammonia is $3.41 . "$ What information is missing from this statement?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:53

Problem 77

Consider the following reaction at a certain temperature:
$$
2 \mathrm{NO}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{NO}_{2}(g)
$$
A reaction mixture contains $0.70 \mathrm{~atm}$ of $\mathrm{O}_{2}$ and $0.81 \mathrm{~atm}$ of NO. When equilibrium is established, the total pressure in the reaction vessel is $1.20 \mathrm{~atm}$. Find $\mathrm{K}$.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:08

Problem 78

Derive the relationship
$$
K=K_{\mathrm{c}} \times(R T)^{\Delta n_{\mathrm{g}}}
$$
where $K_{\mathrm{c}}$ is the equilibrium constant using molarities and $\Delta n_{\mathrm{g}}$ is the change in the number of moles of gas in the reaction (see page 310 ). (Hint: Recall that $P_{\mathrm{A}}=n_{\mathrm{A}} R \mathrm{~T} / \mathrm{V}$ and $\left.n_{\mathrm{A}} / V=[\mathrm{A}] .\right)$

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:31

Problem 79

Ammonia can decompose into its constituent elements according to the reaction
$$
2 \mathrm{NH}_{3}(g) \rightleftharpoons \mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g)
$$
The equilibrium constant for the decomposition at a certain temperature is $2.5 .$ Calculate the partial pressures of all the gases at equilibrium if ammonia with a pressure of 1.00 atm is sealed in a $3.0-\mathrm{L}$ flask.

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:59

Problem 80

Hydrogen iodide gas decomposes to hydrogen gas and iodine gas:
$$
2 \mathrm{HI}(g) \rightleftharpoons \mathrm{H}_{2}(g)+\mathrm{I}_{2}(g)
$$
To determine the equilibrium constant of the system, identical one-liter glass bulbs are filled with $3.20 \mathrm{~g}$ of HI and maintained at a certain temperature. Each bulb is periodically opened and analyzed for iodine formation by titration with sodium thiosulfate, $\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$
$$
\mathrm{I}_{2}(a q)+2 \mathrm{~S}_{2} \mathrm{O}_{3}{ }^{2-}(a q) \longrightarrow \mathrm{S}_{4} \mathrm{O}_{6}{ }^{2-}(a q)+2 \mathrm{I}^{-}(a q)
$$
It is determined that when equilibrium is reached, $37.0 \mathrm{~mL}$ of $0.200 \mathrm{M} \mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}$ is required to titrate the iodine. What is $K$ at the temperature of the experiment?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:32

Problem 81

For the system
$$
\mathrm{SO}_{3}(g) \rightleftharpoons \mathrm{SO}_{2}(g)+\frac{1}{2} \mathrm{O}_{2}(g)
$$
at $1000 \mathrm{~K}, K=0.45 .$ Sulfur trioxide, originally at $1.00 \mathrm{~atm}$ pressure, partially dissociates to $\mathrm{SO}_{2}$ and $\mathrm{O}_{2}$ at $1000 \mathrm{~K}$. What is its partial pressure at equilibrium?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
02:00

Problem 82

A student studies the equilibrium
$$
\mathrm{I}_{2}(g) \rightleftharpoons 2 \mathrm{I}(g)
$$
at a high temperature. She finds that the total pressure at equilibrium is $40 \%$ greater than it was originally, when only $\mathrm{I}_{2}$ was present. What is $K$ for this reaction at that temperature?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
03:36

Problem 83

At a certain temperature, the reaction
$$
\mathrm{Xe}(g)+2 \mathrm{~F}_{2}(g) \rightleftharpoons \mathrm{XeF}_{4}(g)
$$
gives a $50.0 \%$ yield of $\mathrm{XeF}_{4},$ starting with $\mathrm{Xe}\left(P_{\mathrm{Xe}}=0.20 \mathrm{~atm}\right)$ and $\mathrm{F}_{2}\left(P_{\mathrm{F}_{2}}=0.40 \mathrm{~atm}\right) .$ Calculate $K$ at this temperature. What must the initial pressure of $\mathrm{F}_{2}$ be to convert $75.0 \%$ of the xenon to $\mathrm{XeF}_{4}$ ?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
04:44

Problem 84

Benzaldehyde, a flavoring agent, is obtained by the dehydrogenation of benzyl alcohol.
$$
\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{2} \mathrm{OH}(g) \rightleftharpoons \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}(g)+\mathrm{H}_{2}(g)
$$
$K$ for the reaction at $250^{\circ} \mathrm{C}$ is $0.56 .$ If $1.50 \mathrm{~g}$ of benzyl alcohol is placed in a $2.0-\mathrm{L}$ flask and heated to $250^{\circ} \mathrm{C}$
(a) what is the partial pressure of the benzaldehyde when equilibrium is established?
(b) how many grams of benzyl alcohol remain at equilibrium?

Eileen Sullivan
Eileen Sullivan
Numerade Educator
01:05

Problem 85

Hydrogen and nitrogen react to form $\mathrm{NH}_{3}$
$$
3 \mathrm{H}_{2}(g)+\mathrm{N}_{2}(g) \rightleftharpoons 2 \mathrm{NH}_{3}(g)
$$
At a certain temperature, it is determined that an equilibrium mixture of $\mathrm{N}_{2}, \mathrm{H}_{2},$ and $\mathrm{NH}_{3}$ has a total pressure of $3.065 \mathrm{~atm} .$ The mixture has $20.4 \% \mathrm{NH}_{3} .$ What is $K$ at that temperature?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:01

Problem 86

At $165^{\circ} \mathrm{C}$, a solid chloride $(\mathrm{X})$ reacts with $0.0417 \mathrm{~mol}$ of steam to form the solid oxychloride, $\mathrm{Y},$ and $\mathrm{HCl}$ gas. Steam and HCl have a 1: 2 stoichiometric ratio in the reaction
$$
\mathrm{X}(s)+\mathrm{H}_{2} \mathrm{O}(g) \rightleftharpoons \mathrm{Y}(s)+2 \mathrm{HCl}(g)
$$
When the reaction reaches equilibrium, the gases are transferred without loss to a $2.50-\mathrm{L}$ vessel. The temperature is kept at $165^{\circ} \mathrm{C}$. Sufficient silver(I) ion is added to precipitate the chloride as AgCl. If $7.29 \mathrm{~g}$ of $\mathrm{AgCl}$ are obtained, what is $K$ for the reaction of the chloride with steam at $165^{\circ} \mathrm{C} ?$

Eileen Sullivan
Eileen Sullivan
Numerade Educator