General Chemistry
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At 298 K, the equilibria given below are observed:
HSO (g) + NO2 (g) ⇌ HSO2 (g) + NO (g); K1 = 9.6 × 10−12
SO (g) + NO2 (g) ⇌ SO2 (g) + NO (g); K2 = 1.4 × 10−11
What is the equilibrium constant Keq for the following reaction?
HSO2 (s) + SO (g) ⇌ HSO (g) + SO2 (g)
Given the following data at 1500 K:
Fe2O3(s) ⇌ 2 Fe(l) + 3/2 O2(g); K1 = 5.0 x 10-18
Fe3O4(s) ⇌ 3 Fe(l) + 2 O2(g); K2 = 7.0 x 10-22
Calculate the equilibrium constant at the same temperature for the reaction 2 Fe3O4(s) + 1/2 O2(g) ⇌ 3 Fe2O3(s).
The equilibrium state for the reaction X2 + Y2 ⇌ 2 XY is depicted in the following image.
Which rate constant, kr or kf, is bigger? Explain.
Consider the following equilibrium:
H2O (l) ⇌ H2O (g)
At 70°C, what is the value of Kp for this reaction?
The vapor pressure of any liquid and the pressure exerted by its vapor are equal when the two are in equilibrium. Determine the value of Kp at the normal boiling point of a liquid in equilibrium with its vapor.
The equilibrium constant for the following decomposition reaction at 75.0 °C is 2.73.
NH3BF3(s) ⇌ NH3(g) + BF3(g)
What is the minimum amount of NH3BF3(s) in grams that has to be added to a 0.350 L flask in order to reach equilibrium?
What are the equilibrium concentrations of NH3 and BF3 if a sample of NH3BF3(s) is put inside a closed container at 75.0 °C and allowed to reach equilibrium?
The equilibrium constant for the following decomposition reaction at 212 °C is 1.20.
Ca(OCl)2(s) → Ca(s) + Cl2(g) + O2(g)
What are the equilibrium concentrations of Cl2 and O2 if a sample of Ca(OCl)2(s) is put inside a closed container at 212 °C and allowed to reach equilibrium?
For the reaction A + X ⇌ B, where X = C (blue), D (orange), or E (grey), refer to the three images below showing the reaction at equilibrium at the same temperature. Arrange Keq for the three reactions from smallest to largest.
A dry ice container with a capacity of 20.0 US liquid quarts was used to hold cylindrical dry ice pellets. Assuming that each pure cylindrical dry ice pellet has a density of 1.6 g/cm3, a diameter of 1.6 cm, and a length of 6.0 cm, find the number of pellets required to saturate the container with gaseous carbon dioxide. The equilibrium constant Kc for the sublimation of carbon dioxide is 1889.2.
CO2 (s) ⇌ CO2 (g)
Like naphthalene balls, 1,4-Dichlorobenzene (para-dichlorobenzene) balls are used to kill moth larvae by their slight sublimation at room temperature. A reasonable amount of these were left exposed in a 5.0 m by 5.0 m by 5.0 m room at 25 °C. Assuming that these spheres are pure solid para-dichlorobenzene and that the Kc value for the sublimation reaction is 2.72×10−13 at 25 °C, determine the number of gaseous para-dichlorobenzene molecules present in the room at equilibrium.
C6H4Cl2 (s) ⇌ C6H4Cl2 (g)
Nitrogen and hydrogen combine to form ammonia. The Kp of the reaction at 25 °C is 1.4×10–6.
N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g)
Calculate the number of molecules of ammonia present at equilibrium in 11 million cubic meters of air at 25 °C and 730 mmHg. Note that the percent nitrogen and hydrogen in the air are 78.1 % and 0.00005 % respectively.
Butanoic acid was reacted with methanol at 323 K. The equilibrium constant of the reaction at this temperature is 9.0.
CH3OH (aq) + CH3CH2CH2CO2H (aq) ⇌ CH3CH2CH2CO2CH3 (aq) + H2O (aq)
Calculate the number of moles of methyl butanoate present in equilibrium with 4.0 mol of water, 2.0 mol of methanol, and 2.0 mol of butanoic acid at 323 K.
Hydrogen chloride gas can be rapidly formed by directly combining hydrogen gas and chlorine gas above 250 °C. If the Kc for the reaction is 121, and a mixture of H2, Cl2, and HCl at equilibrium contains 1.54×10-3 M H2 and 1.54×10-3 M Cl2, determine the concentration of HCl.
H2 (g) + Cl2 (g) ⇌ 2 HCl (g)
Liquid dinitrogen tetroxide is an oxidizing substance that consists of a mixture of colorless N2O4 and red-brown NO2. If the value of Kc for the equilibrium of the two gases is 0.212 at 100 °C, will a gas be in a much greater concentration than the other at equilibrium? Calculate the equilibrium concentration of NO2 if the equilibrium concentration of N2O4 in a reaction mixture is 2.00×10-3 M.
N2O4 (g) ⇌ 2 NO2 (g)
The reaction P ⇌ Q represents the interconversion of P molecules (orange) and Q molecules (purple). The diagrams below depict four separate experiments showing the progress of the reaction with time:
Calculate the value Kc for the reaction P ⇌ Q.
At 27.0 °C, the aqueous reaction between CH3OH and HBr is as follows: CH3OH(aq) + HBr(aq) → CH3Br(aq) + H2O(l). What is the rate constant for the reverse reaction (kr) if the rate constant for the forward reaction (kf) and equilibrium constant (Kc) at 27.0 °C are, respectively, 1.67×10—4 M—1•s—1 and 1.20×102?
The equilibrium constant (Kp) for the oxidation of nitric oxide (NO) is 1152 at 150 °C.2 NO(g) + O2(g) ⇌ 2 NO2(g)In the reaction mixture at equilibrium, O2 has a partial pressure of 0.345 atm while the partial pressure of NO2 is 0.225 atm. Calculate the partial pressure of NO at equilibrium.
The equilibrium constant (Kc) of the reaction MgC2O4(s) ⇌ Mg2+(aq) + C2O42–(aq) at 25.0°C is 8.6×10–5. In a saturated solution of MgC2O4, calculate the equilibrium concentrations of Mg2+ and C2O42–.
Sulfur dioxide (SO2) gas reacts with oxygen (O2) to produce sulfur trioxide (SO3): 2 SO2(g) + O2(g) ⇌ 2 SO3(g). A 5.5 L reaction vessel is charged with a mixture of SO2 and O2 at 300 °C. When the equilibrium was established, the mixture had the three gases at these partial pressures: PSO2 = 1.15 atm, PO2 = 2.35 atm, and PSO3 = 0.855 atm. Determine Kp.
The diagram below shows nitric oxide (NO) reacting with oxygen (O2) to form nitrogen dioxide (NO2).2 NO(g) + O2(g) ⇌ 2 NO2(g)Using the information in the diagram, calculate the value of the equilibrium constant, Kc, for the reaction. Assume the volume of the container is 3.4 L.
In an equilibrium mixture, [SO2] = 3.50 M and [SO3] = 9.20 M. Calculate [O2] at equilibrium for the mixture.
2 SO2(g) + O2(g) ⇌ 2 SO3(g), Keq = 560
At 30 ºC, the reaction A(g) + 2 B(g) ⇌ 2 C(g) was found to have equilibrium concentrations of [A] = 0.83 M, [B] = 1.12 M, and [C] = 2.25 M. Calculate Kc for the reaction.
The following reaction takes place at very high temperatures:
ZnO(s) + CO(g) ⇌ Zn(l) + CO2(g) Keq = 1.25
If the equilibrium concentration of carbon dioxide (CO2) is found to be 0.213 M, what concentration of carbon monoxide (CO) is present in the reaction mixture?
The formation of hydrogen chloride (HCl) through a reaction of hydrogen (H2) and chlorine (Cl2) is a reversible reaction that takes place according to the following equation:
H2(g) + Cl2(g) ⇌ 2HCl(g)
When the reaction is carried out at 450 °C, the equilibrium mixture contains the following amounts: [H2] = 1.22 M, [Cl2] = 1.35 M and [HCl] = 0.67 M.
Calculate the value of the equilibrium constant (Kc) for this reaction.