7.3 Equilibrium calculations  (Page 8/11)

At a temperature of 60 °C, the vapor pressure of water is 0.196 atm. What is the value of the equilibrium constant K _P for the transformation at 60 °C?

${\text{H}}_2\text{O}(l)\rightleftharpoons {\text{H}}_2\text{O}(g)$

Complete the changes in concentrations (or pressure, if requested) for each of the following reactions.

(a)

$\begin{array}{llll}2{\text{SO}}_3(g)\hfill & \rightleftharpoons \hfill & 2{\text{SO}}_2(g)+\hfill & {\text{O}}_2(g)\hfill \\ \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill & +x\hfill \\ \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill & 0.125M\hfill \end{array}$

(b)

$\begin{array}{lllll}4{\text{NH}}_3(g)\hfill & +3{\text{O}}_2(g)\hfill & \rightleftharpoons \hfill & 2{\text{N}}_2(g)+\hfill & 6{\text{H}}_2\text{O}(g)\hfill \\ \text{\_\_\_}\hfill & 3x\hfill & & \text{\_\_\_}\hfill & \text{\_\_\_}\hfill \\ \text{\_\_\_}\hfill & 0.24M\hfill & & \text{\_\_\_}\hfill & \text{\_\_\_}\hfill \end{array}$

(c) Change in pressure:

$\begin{array}{llll}2{\text{CH}}_4(g)\hfill & \rightleftharpoons \hfill & {\text{C}}_2{\text{H}}_2(g)+\hfill & 3{\text{H}}_2(g)\hfill \\ \text{\_\_\_}\hfill & & x\hfill & \text{\_\_\_}\hfill \\ \text{\_\_\_}\hfill & & 25\text{torr}\hfill & \text{\_\_\_}\hfill \end{array}$

(d) Change in pressure:

$\begin{array}{lllll}{\text{CH}}_4(g)+\hfill & {\text{H}}_2\text{O}(g)\hfill & \rightleftharpoons \hfill & \text{CO}(g)+\hfill & 3{\text{H}}_2(g)\hfill \\ \text{\_\_\_}\hfill & x\hfill & & \text{\_\_\_}\hfill & \text{\_\_\_}\hfill \\ \text{\_\_\_}\hfill & 5\text{atm}\hfill & & \text{\_\_\_}\hfill & \text{\_\_\_}\hfill \end{array}$

(e)

$\begin{array}{llll}{\text{NH}}_4\text{Cl}(s)\hfill & \rightleftharpoons \hfill & {\text{NH}}_3(g)+\hfill & \text{HCl}(g)\hfill \\ & & x\hfill & \text{\_\_\_}\hfill \\ & & \hfill 1.03\times {10}^{\mathrm{-4}}M\hfill & \text{\_\_\_}\hfill \end{array}$

(f) change in pressure:

$\begin{array}{cccc}\text{Ni}(s)+\hfill & 4\text{CO}(g)\hfill & \rightleftharpoons \hfill & \text{Ni}{(\text{CO})}_4(g)\hfill \\ & 4x\hfill & & \text{\_\_\_}\hfill \\ & \hfill 0.40\text{atm}\hfill & & \text{\_\_\_}\hfill \end{array}$

Complete the changes in concentrations (or pressure, if requested) for each of the following reactions.

(a)

$\begin{array}{cccc}2{\text{H}}_2(g)+\hfill & {\text{O}}_2(g)\hfill & \rightleftharpoons \hfill & 2{\text{H}}_2\text{O}(g)\hfill \\ \text{\_\_\_}\hfill & \text{\_\_\_}\hfill & & +2x\hfill \\ \text{\_\_\_}\hfill & \text{\_\_\_}\hfill & & 1.50M\hfill \end{array}$

(b)

$\begin{array}{ccccc}{\text{CS}}_2(g)+\hfill & 4{\text{H}}_2(g)\hfill & \rightleftharpoons \hfill & {\text{CH}}_4(g)+\hfill & 2{\text{H}}_2\text{S}(g)\hfill \\ x\hfill & \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill & \text{\_\_\_}\hfill \\ 0.020M\hfill & \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill & \text{\_\_\_}\hfill \end{array}$

(c) Change in pressure:

$\begin{array}{cccc}{\text{H}}_2(g)+\hfill & {\text{Cl}}_2(g)\hfill & \rightleftharpoons \hfill & 2\text{HCl}(g)\hfill \\ x\hfill & \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill \\ 1.50\text{atm}\hfill & \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill \end{array}$

(d) Change in pressure:

$\begin{array}{ccccc}2{\text{NH}}_3(g)\hfill & +2{\text{O}}_2(g)\hfill & \rightleftharpoons \hfill & {\text{N}}_2\text{O}(g)+\hfill & 3{\text{H}}_2\text{O}(g)\hfill \\ \text{\_\_\_}\hfill & \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill & x\hfill \\ \text{\_\_\_}\hfill & \text{\_\_\_}\hfill & & \text{\_\_\_}\hfill & 60.6\text{torr}\hfill \end{array}$

(e)

$\begin{array}{cccc}{\text{NH}}_4\text{HS}(s)\hfill & \rightleftharpoons \hfill & {\text{NH}}_3(g)+\hfill & {\text{H}}_2\text{S}(g)\hfill \\ & & x\hfill & \text{\_\_\_}\hfill \\ & & 9.8\times {10}^{\mathrm{-6}}M\hfill & \text{\_\_\_}\hfill \end{array}$

(f) Change in pressure:

$\begin{array}{cccc}\text{Fe}(s)+\hfill & 5\text{CO}(g)\hfill & \rightleftharpoons \hfill & \text{Fe}{(\text{CO})}_4(g)\hfill \\ & \text{\_\_\_}\hfill & & x\hfill \\ & \text{\_\_\_}\hfill & & 0.012\text{atm}\hfill \end{array}$

Why are there no changes specified for Ni in [link] , part (f)? What property of Ni does change?

Why are there no changes specified for NH ₄ HS in [link] , part (e)? What property of NH ₄ HS does change?

Analysis of the gases in a sealed reaction vessel containing NH ₃ , N ₂ , and H ₂ at equilibrium at 400 °C established the concentration of N ₂ to be 1.2 M and the concentration of H ₂ to be 0.24 M .

${\text{N}}_2(g)+3{\text{H}}_2(g)\rightleftharpoons 2{\text{NH}}_3(g)K_c=0.50\text{at}400\text{°}\text{C}$

Calculate the equilibrium molar concentration of NH ₃ .

Calculate the number of moles of HI that are at equilibrium with 1.25 mol of H ₂ and 1.25 mol of I ₂ in a 5.00−L flask at 448 °C.

${\text{H}}_2+{\text{I}}_2\rightleftharpoons 2\text{HI}{K}_c=50.2\text{at}448\text{°}\text{C}$

What is the pressure of BrCl in an equilibrium mixture of Cl ₂ , Br ₂ , and BrCl if the pressure of Cl ₂ in the mixture is 0.115 atm and the pressure of Br ₂ in the mixture is 0.450 atm?

${\text{Cl}}_2(g)+{\text{Br}}_2(g)\rightleftharpoons 2\text{BrCl}(g)K_P=4.7\times {10}^{\mathrm{-2}}$

What is the pressure of CO ₂ in a mixture at equilibrium that contains 0.50 atm H ₂ , 2.0 atm of H ₂ O, and 1.0 atm of CO at 990 °C?

${\text{H}}_2(g)+{\text{CO}}_2(g)\rightleftharpoons {\text{H}}_2\text{O}(g)+\text{CO}(g)K_P=1.6\text{at}990\text{°C}$

Cobalt metal can be prepared by reducing cobalt(II) oxide with carbon monoxide.

$\text{CoO}(s)+\text{CO}(g)\rightleftharpoons \text{Co}(s)+{\text{CO}}_2(g)K_c=4.90\times {10}^2\text{at}550\text{°C}$

What concentration of CO remains in an equilibrium mixture with [CO ₂ ] = 0.100 M ?

Carbon reacts with water vapor at elevated temperatures.

$\text{C}(s)+{\text{H}}_2\text{O}(g)\rightleftharpoons \text{CO}(g)+{\text{H}}_2(g)K_c=0.2\text{at}1000\text{°C}$

What is the concentration of CO in an equilibrium mixture with [H ₂ O] = 0.500 M at 1000 °C?

Sodium sulfate 10−hydrate, Na ₂ SO ₄ ·10H ₂ O, dehydrates according to the equation

${\text{Na}}_2{\text{SO}}_4\text{·}10{\text{H}}_2\text{O}(s)\rightleftharpoons {\text{Na}}_2{\text{SO}}_4(s)+10{\text{H}}_2\text{O}(g)K_P=4.08\times {10}^{\mathrm{-25}}\text{at}25\text{°C}$

What is the pressure of water vapor at equilibrium with a mixture of Na ₂ SO ₄ ·10H ₂ O and NaSO ₄ ?

Calcium chloride 6−hydrate, CaCl ₂ ·6H ₂ O, dehydrates according to the equation

${\text{CaCl}}_{\text{2}}\text{·}6{\text{H}}_2\text{O}(s)\rightleftharpoons {\text{CaCl}}_2(s)+6{\text{H}}_2\text{O}(g)K_P=5.09\times {10}^{\mathrm{-44}}\text{at}25\text{°C}$

What is the pressure of water vapor at equilibrium with a mixture of CaCl ₂ ·6H ₂ O and CaCl ₂ ?