Archive for November 2019

Which of the following is always true for a reaction where Kc is at 25°C?

Which of the following is always true for a reaction where Kc is at 25°C?



a. The reaction mixture contains mostly products at equilibrium.
b. The reaction mixture contains mostly reactants at equilibrium.
c. The rate of reaction is very fast.
d. There are approximately equal moles of reactants and products at equilibrium.
e. Both A and C.


Answer: a. The reaction mixture contains mostly products at equilibrium.

Given the equilibrium constants for the equilibria,

Given the equilibrium constants for the equilibria,


NH4+(aq) + H2O(l) NH3(aq) + H3O+(aq); Kc =
2CH3COOH(aq) + 2H2O(l) 2CH3COO−(aq) + 2H3O+(aq); Kc =
determine Kc for the following equilibrium.
CH3COOH(aq) + NH3(aq) CH3COO−(aq) + NH4+(aq)


a. 3.08 x10^4
b. 3.25 x10^-5
c. 9.96 x10^-15
d. 1.00 x10^14
e. 1.75 x10^-5


Answer: a. 3.08 x10^4

At equilibrium, it was found that the concentration of H2 was 0.0367 M, the concentration of N2 was 0.0122 M, and the concentration of NH3 was 0.170 M. What was the initial concentration of ammonia?

A sample of ammonia gas was allowed to come to equilibrium at 400 K.

2NH3(g) N2(g) + 3H2(g)

At equilibrium, it was found that the concentration of H2 was 0.0367 M, the concentration of N2 was 0.0122 M, and the concentration of NH3 was 0.170 M. What was the initial concentration of ammonia?



a. 0.122 M
b. 0.146 M
c. 0.218 M
d. 0.182 M
e. 0.194 M


Answer: e. 0.194 M

For the reaction Br2(g) + Cl2(g) 2BrCl(g), at equilibrium, it is found that the concentrations of Br2, Cl2, and BrCl are 0.277 M, 0.388 M, and M, respectively. What is the value of Kc?

For the reaction Br2(g) + Cl2(g) 2BrCl(g), at equilibrium, it is found that the concentrations of Br2, Cl2, and BrCl are 0.277 M, 0.388 M, and M, respectively. What is the value of Kc?


a. 3.01 x 10^-5
b. 1.67 x 10^-2
c. 5.97 x 10^1
d. 3.32 x 10^4
e. 3.24 x 10^-6


Answer: a. 3.01 x 10^-5

What is the balanced equation for the following equilibrium expression?

What is the balanced equation for the following equilibrium expression?


a. 6SO2(g) + 3O2(g) 6SO3(g)
b. 6SO3(g) 6SO2(g) + 3O2(g)
c. 6SO3(aq) 6SO2(aq) + 3O2(aq)
d. 6SO2(aq) + 3O2(aq) 6SO3(aq)
e. SO2(g) + O2(g) SO3(g)


Answer: a. 6SO2(g) + 3O2(g) 6SO3(g)

A 25.00-L vessel at 700 K initially contains HI(g) at a pressure of 6.00 atm; at equilibrium, it is found that the partial pressure of H2(g) is 0.581 atm. What is the partial pressure of HI(g) at equilibrium?

A 25.00-L vessel at 700 K initially contains HI(g) at a pressure of 6.00 atm; at equilibrium, it is found that the partial pressure of H2(g) is 0.581 atm. What is the partial pressure of HI(g) at equilibrium?


2HI(g) H2(g) + I2(g)


a. 6.00 atm
b. 5.42 atm
c. 4.84 atm
d. 6.58 atm
e. 0.581 atm


Answer: c. 4.84 atm

The value of Kp at 390.°C for the reversible reaction given below is 7.95 × 10−3. Calculate the value of Kp at 25°C. ΔH0 = 162 kJ/mol, R = 8.314 J/mol•K

The value of Kp at 390.°C for the reversible reaction given below is 7.95 × 10−3. Calculate the value of Kp at 25°C. ΔH0 = 162 kJ/mol, R = 8.314 J/mol•K



A(g) + B(g) C(g)

a. 2.8 × 10^−2
b. 1.8 × 10^−18
c. 6.3 × 10^−12
d. 3.0 × 10^−14
e. 3.4 × 10^13


Answer: b. 1.8 × 10^−18

The van't Hoff equation relates two equilibrium constants at two different temperatures. Consider a reaction where K298 = 16.3 and ΔH0 = −116 kJ/mol. Which of the following statements is true?

The van't Hoff equation relates two equilibrium constants at two different temperatures.

Consider a reaction where K298 = 16.3 and ΔH0 = −116 kJ/mol. Which of the following statements is true?



a. The reverse reaction is favored at 298 K.
b. A decrease in temperature will cause the forward reaction to be favored more.
c. An increase in temperature will cause the forward reaction to be favored more.
d. The value of K would be larger at 398 K.
e. The reaction is endothermic.


Answer: b. A decrease in temperature will cause the forward reaction to be favored more.

Consider the following reaction at 25°C for which ΔH0 is −26.9 kJ and ΔS0 is 11.4 J/K. Evaluate the equilibrium constant, Kp, for the reaction at 25°C. R = 8.314 J/mol•K

Consider the following reaction at 25°C for which ΔH0 is −26.9 kJ and ΔS0 is 11.4 J/K. Evaluate the equilibrium constant, Kp, for the reaction at 25°C. R = 8.314 J/mol•K


I2(g) + Cl2(g) 2ICl(g)

a. 3.6 × 10^6
b. 4.2 × 10^3
c. 2.0 × 10^5
d. 6.7 × 10^8
e. 4.9 × 10^−6


Answer: c. 2.0 × 10^5

Which of the following pairs are incorrectly matched?

Which of the following pairs are incorrectly matched?



a. Negative ΔG0 / K > 1
b. Product-favored / K > 1
c. Reactant-favored / positive ΔG0
d. K = 0.053 / ΔG0 must be positive
e. ΔG0 = −16 kJ / K must be < 1


Answer: e. ΔG0 = −16 kJ / K must be < 1

Which of the following statements about ΔG0 and the thermodynamic equilibrium constant is false?

Which of the following statements about ΔG0 and the thermodynamic equilibrium constant is false?



a. ΔG0 and K are both indicators of the direction of a spontaneous reaction.
b. When ΔG0 < 0, the forward reaction is favored.
c. When K < 1, the reverse reaction is favored.
d. There is a mathematical relationship between ΔG0 and K.
e. When ΔG0 < 0, K < 1.


Answer: e. When ΔG0 < 0, K < 1.

CO(g) initially at 2.00 atm is in contact with graphite until equilibrium is reached. What is the partial pressure of CO2(g) at equilibrium?

At 1470 K the value of Kp = 6.0 × 10−4 for the reaction below:
2CO(g) C (graphite) + CO2(g)

CO(g) initially at 2.00 atm is in contact with graphite until equilibrium is reached. What is the partial pressure of CO2(g) at equilibrium?



a. 0.0024 atm
b. 0.00030 atm
c. 0.0012 atm
d. 0.00060 atm
e. 0.00015 atm


Answer: a. 0.0024 atm

At equilibrium, the pressure of NH3(g) was found to be 1.75 atm. What is the equilibrium constant, Kc, for the decomposition at this temperature?

A sample of only solid ammonium chloride was heated in a 1.00-L container at 500.°C:
NH4Cl(s) NH3(g) + HCl(g)

At equilibrium, the pressure of NH3(g) was found to be 1.75 atm. What is the equilibrium constant, Kc, for the decomposition at this temperature?


a. 7.6 × 10^−4
b. 1.2 × 10^4
c. 4.8 × 10^−2
d. 1.9 × 10^2
e. 1.8 × 10^−3


Answer: a. 7.6 × 10^−4

Once equilibrium is established, which of the following would cause this reaction to favor the products more?

Consider the equilibrium decomposition of ammonium bromide.
NH4Br(s) NH3(g) + HBr(g)

Once equilibrium is established, which of the following would cause this reaction to favor the products more?



a. Increase the total pressure.
b. Increase the amount of NH4Br.
c. Decrease the amount of NH4Br.
d. Increase PHBr.
e. Decrease PNH2 .


Answer: e. Decrease PNH2.

Consider the following heterogeneous reaction: Mg(s) + 2H3O+(aq) Mg2+(aq) + H2(g) + 2H2O

Consider the following heterogeneous reaction:
Mg(s) + 2H3O+(aq) Mg2+(aq) + H2(g) + 2H2O


Which of the following statements is false?
a. The amount of magnesium present does not affect the equilibrium position.
b. Adding 1.0 atm of N2 to the system would cause the reverse reaction to be favored.
c. Increasing causes the forward reaction to be favored.
d. Increasing [H3O+] causes the forward reaction to be favored.
e. Decreasing [Mg2+] causes the forward reaction to be favored.


Answer: c. Increasing causes the forward reaction to be favored.

Which one of the following would force the forward reaction to completion?

Which one of the following would force the forward reaction to completion?


CaCO3(s) + 2H3O+(aq) Ca2+(aq) + 3H2O + CO2(g)

a. Removing some H3O+ from the reaction mixture, by neutralizing it with base.
b. Adding more Ca2+ to the mixture.
c. Removing CO2 as it is formed.
d. Adding CO2 to the reaction mixture.
e. None of these would have any effect on the amount of CaCO3 consumed.


Answer: c. Removing CO2 as it is formed.

Given the equilibrium reaction: ZnCO3(s) ZnO(s) + CO2(g) Which one of the following statements is true?

Given the equilibrium reaction:
ZnCO3(s) ZnO(s) + CO2(g)
Which one of the following statements is true?


a. Equal concentrations of ZnO(s) and CO2(g) would result from the decomposition of a given amount of ZnCO3(s).
b. The same equilibrium condition would result if we started with only pure ZnCO3(s) in a closed container as if we started with only pure ZnO(s) in a closed container.
c. Introducing 1.0 atm pressure of N2(g) into the system at equilibrium in a closed container would result in more ZnCO3(s) being formed.
d. Decreasing the volume of the closed system initially at equilibrium, at constant temperature, would result in more ZnCO3(s) being formed.
e. At equilibrium conditions, the forward and reverse reactions have stopped.


Answer: d. Decreasing the volume of the closed system initially at equilibrium, at constant temperature, would result in more ZnCO3(s) being formed.

The gas phase system below is at equilibrium at 200°C with the following partial pressures: 0.20 atm A, 0.20 atm B, 0.10 atm C, and 0.40 atm D. If an additional 0.30 atm C is introduced into the reaction vessel, what will be the partial pressure of C at 200°C when equilibrium is re-established?

The gas phase system below is at equilibrium at 200°C with the following partial pressures: 0.20 atm A, 0.20 atm B, 0.10 atm C, and 0.40 atm D. If an additional 0.30 atm C is introduced into the reaction vessel, what will be the partial pressure of C at 200°C when equilibrium is re-established?



A(g) + B(g) C(g) + D(g)

a. 0.60 atm
b. 0.30 atm
c. 0.50 atm
d. 0.75 atm
e. 0.45 atm


Answer: b. 0.30 atm

The equilibrium constant, Kp, for the following reaction is 280. at 150.°C. Suppose that a quantity of IBr is placed in a closed reaction vessel and the system is allowed to come to equilibrium at 150.°C. When equilibrium is established, the pressure of IBr is 0.200 atm. What is the total pressure inside the system at equilibrium?

The equilibrium constant, Kp, for the following reaction is 280. at 150.°C. Suppose that a quantity of IBr is placed in a closed reaction vessel and the system is allowed to come to equilibrium at 150.°C. When equilibrium is established, the pressure of IBr is 0.200 atm. What is the total pressure inside the system at equilibrium?


I2(g) + Br2(g) 2IBr(g) + 11.7 kJ

a. 0.176 atm
b. 0.212 atm
c. 0.224 atm
d. 0.334 atm
e. 0.536 atm


Answer: c. 0.224 atm

A sample of COCl2 is placed in a closed 15.0-liter vessel at 25°C, and it exerts a pressure of 4.65 atm before decomposition begins. What will be the total pressure at equilibrium?

For the reaction below, Kp = 6.70 × 10−3 at 25°C.
COCl2(g) CO(g) + Cl2(g)

A sample of COCl2 is placed in a closed 15.0-liter vessel at 25°C, and it exerts a pressure of 4.65 atm before decomposition begins. What will be the total pressure at equilibrium?



a. 1.68 atm
b. 3.80 atm
c. 5.03 atm
d. 4.65 atm
e. 4.83 atm


Answer: e. 4.83 atm

The equilibrium constant, Kp, for the following reaction is 355 at 175°C. If one mole of each A, B and C is placed in a 2.00 L reactor at 175°C, what is the partial pressure of A at equilibrium?

The equilibrium constant, Kp, for the following reaction is 355 at 175°C. If one mole of each A, B and C is placed in a 2.00 L reactor at 175°C, what is the partial pressure of A at equilibrium?



2A B + C

a. 8.48 atm
b. 1.44 atm
c. 26.9 atm
d. 9.92 atm
e. 2.00 atm


Answer: b. 1.44 atm

For the reaction below, Kp = 1.59 at 100°C. If 1.0 g of SrCO3 is placed in an empty 5.00 L reactor and allowed to reach equilibrium, what will be the pressure in the reactor?

For the reaction below, Kp = 1.59 at 100°C. If 1.0 g of SrCO3 is placed in an empty 5.00 L reactor and allowed to reach equilibrium, what will be the pressure in the reactor?


SrCO3(s) SrO(s) + CO2(g)

a. 1.59 atm
b. 1.26 atm
c. 2.53 atm
d. 1.0 atm
e. 3.18 atm


Answer: a. 1.59 atm

The equilibrium constant, Kp, for the following reaction is 280. at 150.°C. Suppose that a quantity of IBr is placed in a closed reaction vessel and the system is allowed to come to equilibrium at 150.°C. When equilibrium is established, the pressure of IBr is 0.200 atm. What is the pressure of I2 at equilibrium?

The equilibrium constant, Kp, for the following reaction is 280. at 150.°C. Suppose that a quantity of IBr is placed in a closed reaction vessel and the system is allowed to come to equilibrium at 150.°C. When equilibrium is established, the pressure of IBr is 0.200 atm. What is the pressure of I2 at equilibrium?


I2(g) + Br2(g) 2IBr(g) + 11.7 kJ

a. 0.168 atm
b. 0.096 atm
c. 0.067 atm
d. 0.012 atm
e. 0.00014 atm


Answer: d. 0.012 atm

A sample of COCl2 is placed in a closed 15.0-liter vessel at 25°C, and it exerts a pressure of 4.65 atm before decomposition begins. What will be the partial pressure of Cl2 at equilibrium?

For the reaction below, Kp = 6.70 × 10−3 at 25°C.
COCl2(g) CO(g) + Cl2(g)

A sample of COCl2 is placed in a closed 15.0-liter vessel at 25°C, and it exerts a pressure of 4.65 atm before decomposition begins. What will be the partial pressure of Cl2 at equilibrium?



a. 0.173 atm
b. 0.206 atm
c. 0.566 atm
d. 2.14 atm
e. 1.16 atm


Answer: a. 0.173 atm

Certain amounts of the hypothetical substances A2 and B are mixed in a 3.00-liter container at 300. K. When equilibrium is established for the reaction the following amounts are present: 0.200 mol of A2, 0.400 mol of B, 0.200 mol of D, and 0.100 mol of E. What is Kp, the equilibrium constant, in terms of partial pressures, for this reaction?

Certain amounts of the hypothetical substances A2 and B are mixed in a 3.00-liter container at 300. K. When equilibrium is established for the reaction the following amounts are present: 0.200 mol of A2, 0.400 mol of B, 0.200 mol of D, and 0.100 mol of E. What is Kp, the equilibrium constant, in terms of partial pressures, for this reaction?



A2(g) + 3B(g) 2D(g) + E(g)

a. 16.4
b. 0.084
c. 3.81 × 10^−2
d. 1.42 × 10^−2
e. 2.50 × 10^−1


Answer: c. 3.81 × 10^−2

Certain amounts of the hypothetical substances A2 and B are mixed at 300. K. When equilibrium is established for the reaction below, the following amounts were present in a 3.00-liter container: 0.200 mole of A2, 0.400 mole of B, 0.200 mole of D, and 0.100 mole of E. What is Kp, the equilibrium constant, in terms of partial pressures (atm), for this reaction?

Certain amounts of the hypothetical substances A2 and B are mixed at 300. K. When equilibrium is established for the reaction below, the following amounts were present in a 3.00-liter container: 0.200 mole of A2, 0.400 mole of B, 0.200 mole of D, and 0.100 mole of E. What is Kp, the equilibrium constant, in terms of partial pressures (atm), for this reaction?



A2(g) + 3B(g) 2D(g) + 3E(g)

a. 16.4
b. 0.084
c. 3.81 × 10^−2
d. 2.57 × 10^−2
e. 1.46 × 10^−2


Answer: d. 2.57 × 10^−2

At 250.°C a sample of PCl5 was placed in a 24-liter evacuated reaction vessel and allowed to come to equilibrium. Analysis showed that at equilibrium 0.42 mole of PCl5, 0.64 mole of PCl3, and 0.64 mole of Cl2 were present in the vessel. Calculate Kp for the reaction at 250.°C.

Given:
PCl5(g) PCl3(g) + Cl2(g)

At 250.°C a sample of PCl5 was placed in a 24-liter evacuated reaction vessel and allowed to come to equilibrium. Analysis showed that at equilibrium 0.42 mole of PCl5, 0.64 mole of PCl3, and 0.64 mole of Cl2 were present in the vessel. Calculate Kp for the reaction at 250.°C.



a. 1.2
b. 1.3
c. 1.5
d. 1.8
e. 2.2


Answer: d. 1.8

The partial pressure of a certain gas in a system at equilibrium at 10.°C is experimentally determined to be 0.340 atmosphere. What is its concentration in moles per liter?

The partial pressure of a certain gas in a system at equilibrium at 10.°C is experimentally determined to be 0.340 atmosphere. What is its concentration in moles per liter?



a. 4.14 × 10−1 M
b. 1.46 × 10−2 M
c. 68.2 M
d. 2.79 × 10−1 M
e. 7.90 M


Answer: b. 1.46 × 10−2 M

Phosphorus pentafluoride, PF5(g), partially decomposes to PF3(g) and F2(g) at a temperature of 600 K. A 2.0-liter container is filled with pure PF5. At a temperature of 600 K, the initial pressure of PF5 is 2.0 atm. When equilibrium is reached, half of the original amount of PF5 has decomposed. The equilibrium constant, Kp, is ____.

Phosphorus pentafluoride, PF5(g), partially decomposes to PF3(g) and F2(g) at a temperature of 600 K. A 2.0-liter container is filled with pure PF5. At a temperature of 600 K, the initial pressure of PF5 is 2.0 atm. When equilibrium is reached, half of the original amount of PF5 has decomposed. The equilibrium constant, Kp, is ____.



PF5(g) PF3(g) + F2(g)

a. 0.0025
b. 0.12
c. 0.25
d. 0.50
e. 1.0


Answer: e. 1.0

At 500°C, the following reaction has Kp = 133. If a reaction is initiated with the partial pressure of each gas at 1.0 atm, what is the total pressure of the reaction mixture at equilibrium?

At 500°C, the following reaction has Kp = 133. If a reaction is initiated with the partial pressure of each gas at 1.0 atm, what is the total pressure of the reaction mixture at equilibrium?


H2(g) + Br2(g) 2 HBr(g)

a. 1.0 atm
b. 3.0 atm
c. 0.77 atm
d. 2.0 atm
e. 4.0 atm


Answer: b. 3.0 atm

When equilibrium is established for the following reaction at 298 K, the concentration of N2O4 is 1.34 mol/L, and the concentration of NO2 is 0.448 mol/L. Convert these concentrations to partial pressures. What is the total pressure of the system at equilibrium?

When equilibrium is established for the following reaction at 298 K, the concentration of N2O4 is 1.34 mol/L, and the concentration of NO2 is 0.448 mol/L. Convert these concentrations to partial pressures. What is the total pressure of the system at equilibrium?



N2O4(g) 2NO2(g)

a. 2.54 atm
b. 11.6 atm
c. 16.7 atm
d. 34.4 atm
e. 43.8 atm


Answer: e. 43.8 atm

What would be the equilibrium concentration of N2(g) if 0.12 mole of NO(g) was placed in a 1.00-L container at this temperature? What would be the new equilibrium concentration of N2(g) if the volume were halved at this same temperature?

Given:
N2(g) + O2(g) 2NO(g) Kc = 0.16

What would be the equilibrium concentration of N2(g) if 0.12 mole of NO(g) was placed in a 1.00-L container at this temperature? What would be the new equilibrium concentration of N2(g) if the volume were halved at this same temperature?



a. 0.050 M; 0.10 M
b. 0.050 M; 0.12 M
c. 0.070 M; 0.12 M
d. 0.10 M; 0.10 M
e. 0.50 M; 1.0 M


Answer: a. 0.050 M; 0.10 M

What would be the equilibrium concentration of PCl5(g) if 0.20 mole of PCl5(g) was placed in a 1.00-L container at this temperature? What would be the new equilibrium concentration of PCl5(g) if the volume were halved at this same temperature?

Given:
PCl5(g) PCl3(g) + Cl2(g) Kc = 0.040 at 450°C

What would be the equilibrium concentration of PCl5(g) if 0.20 mole of PCl5(g) was placed in a 1.00-L container at this temperature? What would be the new equilibrium concentration of PCl5(g) if the volume were halved at this same temperature?



a. 0.070 M; 0.29 M
b. 0.13 M; 0.29 M
c. 0.13 M; 0.11 M
d. 0.070 M; 0.13 M
e. 0.060 M; 0.14 M


Answer: b. 0.13 M; 0.29 M

When the above system is at equilibrium at 200°C, the concentrations are found to be: [A] = 0.20 M, [B] = [C] = 0.30 M. If the volume of the container is suddenly doubled at 200°C, what will be the new equilibrium concentration of A?

Given:
A(g) B(g) + C(g)

When the above system is at equilibrium at 200°C, the concentrations are found to be: [A] = 0.20 M, [B] = [C] = 0.30 M. If the volume of the container is suddenly doubled at 200°C, what will be the new equilibrium concentration of A?



a. 0.03 M
b. 0.05 M
c. 0.07 M
d. 0.09 M
e. 0.11 M


Answer: c. 0.07 M

When the system is at equilibrium at 200°C, the concentrations are found to be: [A] = 0.20 M, [B] = 0.30 M, [C] = 0.30 M. If the volume of the container is suddenly doubled at 200°C, what will be the new equilibrium concentration of C?

Given:
A(g) B(g) + C(g)

When the system is at equilibrium at 200°C, the concentrations are found to be: [A] = 0.20 M, [B] = 0.30 M, [C] = 0.30 M. If the volume of the container is suddenly doubled at 200°C, what will be the new equilibrium concentration of C?



a. 0.060 M
b. 0.18 M
c. 0.24 M
d. 0.29 M
e. 0.35 M


Answer: b. 0.18 M

A 1.00-liter vessel contains the following equilibrium concentrations at 400°C: N2, 1.00 M; H2, 0.50 M; and NH3, 0.50 M. How many moles of hydrogen must be removed from the vessel in order to increase the concentration of nitrogen to 1.20 M?

A 1.00-liter vessel contains the following equilibrium concentrations at 400°C: N2, 1.00 M; H2, 0.50 M; and NH3, 0.50 M. How many moles of hydrogen must be removed from the vessel in order to increase the concentration of nitrogen to 1.20 M?



N2(g) + 3H2(g) 2NH3(g)

a. 0.94 mol
b. 1.5 mol
c. 0.33 mol
d. 0.76 mol
e. 1.1 mol


Answer: a. 0.94 mol

A system at equilibrium in a 1.0-liter container was found to contain 0.20 mol of A, 0.20 mol of B, 0.40 mol of C, and 0.40 mol of D. If 0.12 mol of A and 0.12 mol of B are added to this system, what will be the new equilibrium concentration of C?

A system at equilibrium in a 1.0-liter container was found to contain 0.20 mol of A, 0.20 mol of B, 0.40 mol of C, and 0.40 mol of D. If 0.12 mol of A and 0.12 mol of B are added to this system, what will be the new equilibrium concentration of C?



A(g) + B(g) C(g) + D(g)

a. 0.32 M
b. 0.13 M
c. 0.24 M
d. 0.40 M
e. 0.48 M


Answer: e. 0.48 M

The following system is at equilibrium with [N2O4] = 0.55 M and [NO2] = 0.25 M. If an additional 0.10 M NO2 is added to the reaction mixture with no change in volume, what will be the new equilibrium concentration of N2O4?

The following system is at equilibrium with [N2O4] = 0.55 M and [NO2] = 0.25 M. If an additional 0.10 M NO2 is added to the reaction mixture with no change in volume, what will be the new equilibrium concentration of N2O4?



N2O4(g) 2NO2(g)

a. 0.59 M
b. 0.65 M
c. 0.26 M
d. 0.45 M
e. 0.70 M


Answer: a. 0.59 M

A system at equilibrium in a 1.0-liter container was found to contain 0.20 mol of A, 0.20 mol of B, 0.40 mol of C, and 0.40 mol of D. If 0.15 mol of A and 0.15 mol of B are added to this system, what will be the new equilibrium concentration of A?

A system at equilibrium in a 1.0-liter container was found to contain 0.20 mol of A, 0.20 mol of B, 0.40 mol of C, and 0.40 mol of D. If 0.15 mol of A and 0.15 mol of B are added to this system, what will be the new equilibrium concentration of A?



A(g) + B(g) C(g) + D(g)

a. 0.050 M
b. 0.10 M
c. 0.20 M
d. 0.25 M
e. 0.30 M


Answer: d. 0.25 M

The Haber process demonstrates that commercial processes do not maximize each factor that affects equilibria but use them in combination to get maximum production. Which of the following statements about the Haber process is false?

The Haber process demonstrates that commercial processes do not maximize each factor that affects equilibria but use them in combination to get maximum production. Which of the following statements about the Haber process is false?


N2(g) + 3H2(g) 2NH3(g) + 92.24 kJ

a. Although Kc is much greater at 25°C, the reaction is carried out at 450°C.
b. A catalyst is used to increase reaction rate.
c. Although the reaction is exothermic, it is carried out at high (450°C) temperature.
d. Although high pressure is unfavorable to the production of the NH3(g), the reaction is carried out under a pressure of 200−1000 atmospheres.
e. The emerging reaction mixture is cooled to remove the NH3 and the N2 and H2 recycled.


Answer: d. Although high pressure is unfavorable to the production of the NH3(g), the reaction is carried out under a pressure of 200−1000 atmospheres.

Which response contains all the choices below that refer to changes that would shift the equilibrium to the right, and no other choices?

Consider the following reversible reaction at equilibrium.
N2(g) + 3H2(g) 2NH3(g) + 9.22 × 104 J

Which response contains all the choices below that refer to changes that would shift the equilibrium to the right, and no other choices?



I. add H2
II. remove N2
III. add an iron catalyst
IV. increase the temperature at constant pressure
V. increase the pressure at constant temperature by decreasing the volume

a. III, IV and V
b. I, IV and V
c. IV and V
d. I, II and III
e. I and V


Answer: e. I and V

Suppose the following reaction is at equilibrium at a given temperature and pressure. The pressure is then increased at constant temperature, by compressing the reaction mixture, and the mixture is allowed to re-establish equilibrium. At the new equilibrium ____.

Suppose the following reaction is at equilibrium at a given temperature and pressure. The pressure is then increased at constant temperature, by compressing the reaction mixture, and the mixture is allowed to re-establish equilibrium. At the new equilibrium ____.



N2(g) + 3H2(g) 2NH3(g)

a. there is more ammonia than there was originally
b. there is less ammonia than there was originally
c. there is the same amount of ammonia present as there was originally
d. the nitrogen is used up completely
e. the amount of ammonia may be either larger or smaller than it was originally, depending on the value of K


Answer: a. there is more ammonia than there was originally

Which of the following statements about the Haber process is false?

Which of the following statements about the Haber process is false?



a. Fritz Haber, a German scientist, developed the process.
b. Higher temperature favors the forward reaction.
c. Most NH3 produced by the Haber process is used to make fertilizer.
d. Ammonia is synthesized from elemental nitrogen and hydrogen.
e. Higher gas pressures favor the forward reaction.


Answer: b. Higher temperature favors the forward reaction.

Which of the following will require the least time for a reaction to reach equilibrium?

Which of the following will require the least time for a reaction to reach equilibrium?



a. Kc is a very small number.
b. Kc is a very large number.
c. Kc is approximately one.
d. Cannot tell without knowing the value of Kc.
e. Cannot tell, since the time required to reach equilibrium does not depend on Kc.


Answer: e. Cannot tell, since the time required to reach equilibrium does not depend on Kc.

In order to increase the yield of SO3, the reaction should be run

For the gas phase reaction below, ΔH0 = −1.6 × 102 kJ for the forward reaction.
SO2 + O2 SO3

In order to increase the yield of SO3, the reaction should be run

a. at high P, high T.
b. at high P, low T.
c. at low P, high T.
d. at low P, low T.
e. at high P, but is independent of T.


Answer: b. at high P, low T.

At equilibrium a 1.0-liter container was found to contain 0.20 mol of A, 0.20 mol of B, 0.40 mol of C, and 0.40 mol of D. If 0.10 mol of A and 0.10 mol of B are added to this system, which of the following statements is true?

At equilibrium a 1.0-liter container was found to contain 0.20 mol of A, 0.20 mol of B, 0.40 mol of C, and 0.40 mol of D. If 0.10 mol of A and 0.10 mol of B are added to this system, which of the following statements is true?


A(g) + B(g) C(g) + D(g)

a. The system remains in equilibrium.
b. Q > Kc
c. More reactants are formed to increase the value of Q.
d. The value of Kc decreases.
e. More products are formed to increase the value of Q.


Answer: e. More products are formed to increase the value of Q.

Consider the following reaction: AB(s) + C2(g) AC(g) + BC(g) + heat Which of the following statements is false?

Consider the following reaction:
AB(s) + C2(g) AC(g) + BC(g) + heat
Which of the following statements is false?



a. Increasing PC2 will cause a shift to the left.
b. Adding a catalyst will not affect the equilibrium.
c. Decreasing the temperature will cause a shift to the right.
d. Adding more AB(s) will not affect the equilibrium.
e. Increasing PAC or PBC will cause a shift to the left.


Answer: a. Increasing PC2 will cause a shift to the left.

Which of the numbered responses lists all the following stresses that would shift the equilibrium to the right (favor the forward reaction), and no other stresses?

Which of the numbered responses lists all the following stresses that would shift the equilibrium to the right (favor the forward reaction), and no other stresses?



2NOCl(g) + 75 kJ 2NO(g) + Cl2(g)

I. Add more NOCl.
II. Remove some Cl2.
III. Lower the temperature.
IV. Add more NO.

a. I and II
b. I, II, and III
c. I and III
d. II and IV
e. II, III, and IV


Answer: a. I and II

Suppose we let this reaction come to equilibrium. Then we increase the temperature of the reaction mixture. What will be the effect on the net amount of SO3(g) present?

Suppose we let this reaction come to equilibrium. Then we increase the temperature of the reaction mixture. What will be the effect on the net amount of SO3(g) present?



2SO2(g) + O2(g) 2SO3(g) + heat

a. It increases.
b. It decreases.
c. It does not change.
d. The question cannot be answered without knowing the value of K.
e. The question cannot be answered without knowing the value of ΔH0.


Answer: b. It decreases.

Decreasing the volume of the container (at constant temperature) after the system below has reached equilibrium would be expected to ____.

Decreasing the volume of the container (at constant temperature) after the system below has reached equilibrium would be expected to ____.



HN3 + 2H2O N2H4 + HNO2

a. produce more HN3 and raise the temperature
b. produce more H2O and lower the temperature
c. produce more N2H4 and raise the temperature
d. produce more HNO2 and lower the temperature
e. have no effect on this equilibrium


Answer: e. have no effect on this equilibrium

Suppose the following reaction is at equilibrium at a given temperature and pressure. The pressure is then increased at constant temperature, by compressing the reaction mixture, and the mixture is allowed to re-establish equilibrium. At the new equilibrium ____.

Suppose the following reaction is at equilibrium at a given temperature and pressure. The pressure is then increased at constant temperature, by compressing the reaction mixture, and the mixture is allowed to re-establish equilibrium. At the new equilibrium ____.



H2(g) + Cl2(g) 2HCl(g)

a. there is more hydrogen chloride than there was originally
b. there is less hydrogen chloride than there was originally
c. there is the same amount of hydrogen chloride as there was originally
d. the hydrogen and chloride are completely used up
e. the amount of hydrogen chloride may be either larger or smaller than it was originally, depending on the value of K


Answer: c. there is the same amount of hydrogen chloride as there was originally

Suppose we let the reaction below come to equilibrium. Then we decrease the total pressure, by increasing the volume of the container. What will be the effect on the numerical value of the equilibrium constant, K?

Suppose we let the reaction below come to equilibrium. Then we decrease the total pressure, by increasing the volume of the container. What will be the effect on the numerical value of the equilibrium constant, K?


2SO2(g) + O2(g) 2SO3(g) + heat

a. It increases.
b. It decreases.
c. It does not change.
d. The question cannot be answered without knowing the initial value of K.
e. The question cannot be answered without knowing the value of ΔH0.


Answer: c. It does not change.

Suppose we let the reaction below come to equilibrium. Then we decrease the total pressure, by increasing the volume of the container. What will be the effect on the net amount of SO3(g) present?

Suppose we let the reaction below come to equilibrium. Then we decrease the total pressure, by increasing the volume of the container. What will be the effect on the net amount of SO3(g) present?



2SO2(g) + O2(g) 2SO3(g)

a. It increases.
b. It decreases.
c. It does not change.
d. The question cannot be answered without knowing the value of K.
e. The question cannot be answered without knowing the value of ΔH0.


Answer: b. It decreases.

Considering the following reaction at equilibrium, identify which of the stresses below would cause more products to form.

Considering the following reaction at equilibrium, identify which of the stresses below would cause more products to form.


CO(g) + Cl2(g) COCl2(g) ΔH0 = −113 kJ/mol

a. Increase the pressure.
b. Increase the [Cl2].
c. Increase the temperature.
d. Both (a) and (b) are correct.
e. All of these are correct.


Answer: d. Both (a) and (b) are correct.

If the system below is at equilibrium in a closed vessel and a small amount of nitrous acid is added, what would be expected to happen?

If the system below is at equilibrium in a closed vessel and a small amount of nitrous acid is added, what would be expected to happen?


HN3 + 2H2O N2H4 + HNO2 ΔH0 = +641 kJ
hydrazoic acid hydrazine nitrous acid

a. Some HN3 would be used up in re-establishing equilibrium.
b. Some HNO2 would be formed in re-establishing equilibrium.
c. Some HNO2 would be formed, and some N2H4 would be lost.
d. More HN3 and H2O would be formed.
e. The temperature would decrease, and the forward reaction would be favored.

Answer: d. More HN3 and H2O would be formed.

For the following system at equilibrium, H2(g) + CO2(g) H2O(g) + CO(g) the removal of some of the H2O(g) would cause (according to LeChatelier's principle)

For the following system at equilibrium,
H2(g) + CO2(g) H2O(g) + CO(g)
the removal of some of the H2O(g) would cause (according to LeChatelier's principle)



a. more H2(g) to be form.
b. more CO2(g) to be form.
c. no change in the amounts of products or reactants.
d. more CO(g) to be form.
e. the amount of CO(g) to remain constant while the amount of H2O(g) increases to the original equilibrium concentration.


Answer: d. more CO(g) to be form.

For the following system at equilibrium, H2(g) + CO2(g) H2O(g) + CO(g) the addition of H2(g) would cause (according to LeChatelier's principle)

For the following system at equilibrium,
H2(g) + CO2(g) H2O(g) + CO(g)
the addition of H2(g) would cause (according to LeChatelier's principle)



a. only more H2O(g) to form.
b. only more CO(g) to form.
c. more H2O(g) and CO(g) to form.
d. only more CO2(g) to form.
e. no change in amounts of products or reactants.


Answer: c. more H2O(g) and CO(g) to form.

Which statement best represents LeChatelier's Principle?

Which statement best represents LeChatelier's Principle?



a. A system in equilibrium will always remain in equilibrium.
b. Only a change in equilibrium will affect the equilibrium of a reaction.
c. When a change is made to a system in equilibrium, equilibrium can never be restored.
d. A system in equilibrium will respond to a change by moving in the direction that reduces the change as it returns to equilibrium.
e. A system in equilibrium will not be affected by a change in concentration.


Answer: d. A system in equilibrium will respond to a change by moving in the direction that reduces the change as it returns to equilibrium.

For the following reaction, Kc is 144 at 200°C. If the reaction were initiated with 0.600 mol of A and 0.200 mol of B in a 2.00-liter container, what would be the equilibrium concentration of A?

For the following reaction, Kc is 144 at 200°C. If the reaction were initiated with 0.600 mol of A and 0.200 mol of B in a 2.00-liter container, what would be the equilibrium concentration of A?



A(g) + B(g) C(g) + D(g)

a. 0.684 M
b. 0.200 M
c. 0.444 M
d. 0.982 M
e. 1.05 M


Answer: b. 0.200 M

For the following system, the equilibrium constant at 445°C is 51.0. If a reaction is initiated with the following initial concentrations, [H2] = 2.06 × 10−2 M, [I2] = 1.45 × 10−2 M, and [HI] = 0, what will be the equilibrium concentration of HI?

For the following system, the equilibrium constant at 445°C is 51.0. If a reaction is initiated with the following initial concentrations, [H2] = 2.06 × 10−2 M, [I2] = 1.45 × 10−2 M, and [HI] = 0, what will be the equilibrium concentration of HI?



H2(g) + I2(g) 2HI(g)

a. 1.8 × 10^−2 M
b. 1.4 × 10^−1 M
c. 2.7 × 10^−1 M
d. 2.6 × 10^−2 M
e. 3.7 × 10^−3 M


Answer: d. 2.6 × 10^−2 M

Kc = 0.040 for the system below at 450°C. If a reaction is initiated with 0.20 mole of Cl2 and 0.20 mole of PCl3 in a 1.0-liter container, what concentration of PCl5 will be present at equilibrium?

Kc = 0.040 for the system below at 450°C. If a reaction is initiated with 0.20 mole of Cl2 and 0.20 mole of PCl3 in a 1.0-liter container, what concentration of PCl5 will be present at equilibrium?



PCl5(g) PCl3(g) + Cl2(g)

a. 0.09 M
b. 0.13 M
c. 0.22 M
d. 0.31 M
e. 0.16 M


Answer: b. 0.13 M

Phosgene, COCl2, is a poisonous gas that decomposes into carbon monoxide and chlorine according to the following equation with Kc = 0.083 at 900°C. If the reaction is initiated with 0.600 mole of COCl2 at 900°C in a 5.00-liter container, what concentration of CO will be present after equilibrium is established?

Phosgene, COCl2, is a poisonous gas that decomposes into carbon monoxide and chlorine according to the following equation with Kc = 0.083 at 900°C. If the reaction is initiated with 0.600 mole of COCl2 at 900°C in a 5.00-liter container, what concentration of CO will be present after equilibrium is established?



COCl2(g) CO(g) + Cl2(g)

a. 0.072 M
b. 0.048 M
c. 0.067 M
d. 0.012 M
e. 0.090 M


Answer: c. 0.067 M

The equilibrium constant, Kc, is 0.022 at 25°C for the reaction below. What is the concentration of PCl5 at equilibrium if a reaction is initiated with 0.80 mole of PCl5 in a 1.00-liter container?

The equilibrium constant, Kc, is 0.022 at 25°C for the reaction below. What is the concentration of PCl5 at equilibrium if a reaction is initiated with 0.80 mole of PCl5 in a 1.00-liter container?



PCl5(g) PCl3(g) + Cl2(g)

a. 0.080 M
b. 0.12 M
c. 0.54 M
d. 0.68 M
e. 0.76 M


Answer: d. 0.68 M

Exactly one mol/L of each of the four gases involved in the following reaction is placed in a reactor at 200°C and allowed to reach equilibrium. What is the equilibrium concentration of H2O?

Exactly one mol/L of each of the four gases involved in the following reaction is placed in a reactor at 200°C and allowed to reach equilibrium. What is the equilibrium concentration of H2O? 



Kc = 2.38 @ 200°C.

CO(g) + H2O(g) CO2(g) + H2(g)

a. 1.21 M
b. 0.213 M
c. 0.787 M
d. 2.38 M
e. 1.0 M


Answer: c. 0.787 M

At 25°C, Kc for the following reaction is 4.66 × 10−3. If 0.800 mol of N2O4 is injected into a closed 1.00-liter glass container at 25°C, what will be the equilibrium concentration of N2O4?

At 25°C, Kc for the following reaction is 4.66 × 10−3. If 0.800 mol of N2O4 is injected into a closed 1.00-liter glass container at 25°C, what will be the equilibrium concentration of N2O4?


N2O4(g) 2NO2(g)

a. 0.016 M
b. 0.770 M
c. 0.088 M
d. 0.236 M
e. 0.667 M


Answer: b. 0.770 M

If 25.0 g of ammonium carbamate is placed in an empty chamber and heated to 100°C, what are the equilibrium concentrations of NH3 and CO2? Kc = 58.3 at 100°C.

Ammonium carbamate decomposes into NH3 and CO2 when heated.
NH4(NH2CO2)(s) 2NH3(g) + CO2(g)

If 25.0 g of ammonium carbamate is placed in an empty chamber and heated to 100°C, what are the equilibrium concentrations of NH3 and CO2? Kc = 58.3 at 100°C.


a. [NH3] = 2.44 M; [CO2] = 4.88 M
b. [NH3] = 4.88 M; [CO2] = 2.44 M
c. [NH3] = 29.2 M; [CO2] = 14.6 M
d. [NH3] = 15.3 M; [CO2] = 7.64 M
e. [NH3] = 10.8 M; [CO2] = 5.40 M


Answer: b. [NH3] = 4.88 M; [CO2] = 2.44 M

For the following reaction, Kc is 144 at 200°C. If 0.400 mol of both A and B are placed in a 2.00-liter container at that temperature, what will be the concentration of C at equilibrium?

For the following reaction, Kc is 144 at 200°C. If 0.400 mol of both A and B are placed in a 2.00-liter container at that temperature, what will be the concentration of C at equilibrium?


A(g) + B(g) C(g) + D(g)

a. 0.015 M
b. 1.64 M
c. 0.200 M
d. 0.185 M
e. 1.13 M


Answer: d. 0.185 M

The equilibrium constant for the following gas phase reaction is 4.0 at a certain temperature. A reaction is carried out at this temperature starting with 2.0 mol/L of CO and 2.0 mol/L of H2O. What will be the equilibrium concentration of H2?

The equilibrium constant for the following gas phase reaction is 4.0 at a certain temperature. A reaction is carried out at this temperature starting with 2.0 mol/L of CO and 2.0 mol/L of H2O. What will be the equilibrium concentration of H2?

CO + H2O CO2 + H2

a. 2.0 M
b. 0.75 M
c. 1.3 M
d. 0.67 M
e. 1.5 M


Answer: c. 1.3 M

A quantity of HI was sealed in a tube, heated to 425°C, and held at this temperature until equilibrium was reached. The concentration of HI in the tube at equilibrium was found to be 0.0706 moles/liter. Calculate the equilibrium concentration of H2 (and I2) for the reaction:

A quantity of HI was sealed in a tube, heated to 425°C, and held at this temperature until equilibrium was reached. The concentration of HI in the tube at equilibrium was found to be 0.0706 moles/liter. Calculate the equilibrium concentration of H2 (and I2) for the reaction:


H2(g) + I2(g) 2HI(g) Kc = 54.6 at 425°C

a. 4.78 × 10^−3 M
b. 9.55 × 10^−3 M
c. 2.34 × 10^−3 M
d. 1.17 × 10^−3 M
e. 1.85 × 10^−4 M


Answer: b. 9.55 × 10^−3 M

Consider the following system. The equilibrium constant for the reaction at 900°C is 0.082. A reaction is initiated with only COCl2 in a 2.0-liter vessel. At equilibrium 2.36 × 10−3 mol of Cl2 is present. How many moles of COCl2 are present at equilibrium?

Consider the following system. The equilibrium constant for the reaction at 900°C is 0.082. A reaction is initiated with only COCl2 in a 2.0-liter vessel. At equilibrium 2.36 × 10−3 mol of Cl2 is present. How many moles of COCl2 are present at equilibrium?


COCl2(g) CO(g) + Cl2(g)

a. 1.4 × 10^−4 mol
b. 1.4 × 10^−3 mol
c. 6.1 × 10^−5 mol
d. 5.8 × 10^−4 mol
e. 3.4 × 10^−5 mol


Answer: e. 3.4 × 10^−5 mol

The numerical value of the equilibrium constant, Kc, for the following gas phase reaction is 0.50 at a certain temperature. When a certain reaction mixture reaches equilibrium, the concentration of O2 is found to be 2.0 M, while the concentration of SO3 is found to be 10 M. What is the equilibrium concentration of SO2 in this mixture?

The numerical value of the equilibrium constant, Kc, for the following gas phase reaction is 0.50 at a certain temperature. When a certain reaction mixture reaches equilibrium, the concentration of O2 is found to be 2.0 M, while the concentration of SO3 is found to be 10 M. What is the equilibrium concentration of SO2 in this mixture?


2SO2 + O2 2SO3

a. 0.50 M
b. 10 M
c. 0.10 M
d. 5.0 M
e. 1.0 M


Answer: b. 10 M

Nitrosyl chloride, NOCl, dissociates on heating as shown below. When a 1.50-gram sample of pure NOCl is heated at 350°C in a volume of 1.00 liter, the percent dissociation is found to be 57.2%. Calculate the equilibrium concentration of NOCl.

Nitrosyl chloride, NOCl, dissociates on heating as shown below. When a 1.50-gram sample of pure NOCl is heated at 350°C in a volume of 1.00 liter, the percent dissociation is found to be 57.2%. Calculate the equilibrium concentration of NOCl.


NOCl(g) NO(g) + Cl2(g)

a. 8.76 × 10^−1 M
b. 9.26 M
c. 9.80 × 10^−3 M
d. 1.31 × 10^−2 M
e. 1.75 × 10^−4 M


Answer: c. 9.80 × 10−3 M

At a certain temperature Kc = 55 and a reaction vessel contains a mixture with the following concentrations: [SO3] = 0.85 M, [NO] = 1.2 M , [SO2] = 1.5 M and [NO2] = 2.0 M. Which of the following statements concerning the reaction and the reaction quotient, Q, is false?

At a certain temperature Kc = 55 and a reaction vessel contains a mixture with the following concentrations: [SO3] = 0.85 M, [NO] = 1.2 M , [SO2] = 1.5 M and [NO2] = 2.0 M. Which of the following statements concerning the reaction and the reaction quotient, Q, is false?


SO3(g) + NO(g) SO2(g) + NO2(g)

a. Q < Kc
b. Q > Kc
c. The reaction is not in equilibrium.
d. Product concentrations will increase as equilibrium is approached.
e. Reactant concentrations will decrease as equilibrium is approached.


Answer: b. Q > Kc

At a certain temperature Kc = 25 and a reaction vessel contains a mixture with the following concentrations: [H2] = 0.10 M, [Br2] = 0.10 M and [HBr] = 0.50 M. Which of the following statements concerning the reaction and the reaction quotient, Q, is true?

At a certain temperature Kc = 25 and a reaction vessel contains a mixture with the following concentrations: [H2] = 0.10 M, [Br2] = 0.10 M and [HBr] = 0.50 M. Which of the following statements concerning the reaction and the reaction quotient, Q, is true?


H2(g) + Br2(g) 2HBr(g)

a. Q = Kc
b. Q < Kc; more HBr will be produced.
c. Q < Kc; more H2 and Br2 will be produced.
d. Q > Kc; more HBr will be produced.
e. Q > Kc; more H2 and Br2 will be produced.


Answer: a. Q = Kc

The equilibrium constant, Kc, for the following reaction is 0.0154 at a high temperature. A mixture in a container at this temperature has the concentrations: [H2] = 1.11 M, [I2] = 1.30 M and [HI] = 0.181 M. Which of the following statements concerning the reaction and the reaction quotient, Q, is true?

The equilibrium constant, Kc, for the following reaction is 0.0154 at a high temperature. A mixture in a container at this temperature has the concentrations: [H2] = 1.11 M, [I2] = 1.30 M and [HI] = 0.181 M. Which of the following statements concerning the reaction and the reaction quotient, Q, is true?


H2(g) + I2(g) 2HI(g)

a. Q = Kc
b. Q > Kc; more HI will be produced.
c. Q > Kc; more H2 and I2 will be produced.
d. Q < Kc; more HI will be produced.
e. Q < Kc; more H2 and I2 will be produced.


Answer: c. Q > Kc; more H2 and I2 will be produced.

The following reaction is initiated and the concentrations are measured after ten minutes:

The following reaction is initiated and the concentrations are measured after ten minutes:


A(g) + 3 B(g) AB3(g) Kc = 1.33 × 10−2
[A] = 1.78 M [B] = 2.21 M [AB3] = 1.19 M

Is the reaction in equilibrium?
a. Yes.
b. No, because Q < K.
c. No, and the [AB3] must increase to establish equilibrium.
d. No, because Q > K.
e. There is no way to tell.


Answer: d. No, because Q > K.

The equilibrium constant for the following gas phase reaction is 0.50 at 600°C. A mixture of HCHO, H2, and CO is introduced into a flask at 600°C. After a short time, analysis of a small amount of the reaction mixture shows the concentrations to be [HCHO] = 1.5 M, [H2] = 0.5 M, and [CO] = 1.0 M. Which of the following statements about this reaction mixture is true?

The equilibrium constant for the following gas phase reaction is 0.50 at 600°C. A mixture of HCHO, H2, and CO is introduced into a flask at 600°C. After a short time, analysis of a small amount of the reaction mixture shows the concentrations to be [HCHO] = 1.5 M, [H2] = 0.5 M, and [CO] = 1.0 M. Which of the following statements about this reaction mixture is true?



HCHO H2 + CO

a. The reaction mixture is at equilibrium.
b. The reaction mixture is not at equilibrium, but no further reaction will occur.
c. The reaction mixture is not at equilibrium, but will move toward equilibrium by forming more HCHO.
d. The reaction mixture is not at equilibrium, but will move toward equilibrium by using up more HCHO.
e. The forward rate of this reaction is the same as the reverse rate.


Answer: d. The reaction mixture is not at equilibrium, but will move toward equilibrium by using up more HCHO.

Which of the following statements about the reaction quotient, Q, is false?

Which of the following statements about the reaction quotient, Q, is false?



a. The value of Q can be used to predict equilibrium concentrations.
b. It has the same expression as Kc.
c. Its value is calculated using nonequilibrium concentrations.
d. If Q > Kc, the reaction must move to equilibrium by forming more reactants.
e. If Q < Kc, the reaction must move to equilibrium by forming more products.


Answer: a. The value of Q can be used to predict equilibrium concentrations.

Calculate the value of the equilibrium constant at the same temperature for

If the equilibrium constant at a certain temperature is 2.1 × 1013 for the following reaction,
4HCl(g) + O2(g) 2Cl2(g) + 2H2O(g)

Calculate the value of the equilibrium constant at the same temperature for


Cl2(g) + H2O(g) HCl(g) + O2(g)

a. 2.2 × 10^−7
b. 3.8 × 10^3
c. 5.3 × 10^12
d. 4.7 × 10^−4
e. 1.2 × 10^−14


Answer: d. 4.7 × 10^−4

Calculate the numerical value of the equilibrium constant for the following reaction at the same temperature.

Given the following reaction and its equilibrium constant at a certain temperature:
N2(g) + 3H2(g) 2NH3(g) Kc = 3.6 × 108

Calculate the numerical value of the equilibrium constant for the following reaction at the same temperature.

NH3(g) N2(g) + H2(g)

a. 2.8 × 10^−9
b. 1.9 × 10^4
c. 1.3 × 10^7
d. 5.3 × 10^−5
e. 7.7 × 10^−18


Answer: d. 5.3 × 10^−5

One (1.0) mole of A and 1.0 mole of B are placed in a 5.0-liter container. After equilibrium has been established, 0.50 mole of D is present in the container. Calculate the equilibrium constant, Kc, for the reaction.

Given:
A(g) + 3B(g) C(g) + 2D(g)

One (1.0) mole of A and 1.0 mole of B are placed in a 5.0-liter container. After equilibrium has been established, 0.50 mole of D is present in the container. Calculate the equilibrium constant, Kc, for the reaction.



a. 1.2
b. 0.68
c. 12
d. 27
e. 1.4 × 102


Answer: d. 27

Consider the following reaction in which all reactants and products are gases. 1.00 mol of A and 2.00 mol of B are placed in a 5.0-liter container. After equilibrium has been established, 0.50 mol of D is present in the container. Calculate the equilibrium constant, Kc, for the reaction.

Consider the following reaction in which all reactants and products are gases. 1.00 mol of A and 2.00 mol of B are placed in a 5.0-liter container. After equilibrium has been established, 0.50 mol of D is present in the container. Calculate the equilibrium constant, Kc, for the reaction.

A + 2B 2C + D

a. 1.0
b. 0.15
c. 0.33
d. 3.0
e. 5.0


Answer: a. 1.0

At equilibrium, the following amounts are found at a certain temperature in a 3.0-liter container: 2.0 mole of Cl2, 0.80 mol of H2O (steam), 0.0030 mol of HCl, and 0.0045 mol of O2. Evaluate Kc at that temperature.

At equilibrium, the following amounts are found at a certain temperature in a 3.0-liter container: 2.0 mole of Cl2, 0.80 mol of H2O (steam), 0.0030 mol of HCl, and 0.0045 mol of O2. Evaluate Kc at that temperature.



2Cl2(g) + 2H2O(g) 4HCl(g) + O2(g)

a. 4.7 × 10^−14
b. 8.4 × 10^−7
c. 1.4 × 10^−13
d. 2.2 × 10^13
e. 7.1 × 10^12


Answer: a. 4.7 × 10^−14

In a 5.0 liter reactor at equilibrium at a constant temperature, it was determined there was 0.45 mol NO, 0.17 mol Br and 1.32 mol NOBr. What is the value of Kc at this temperature?

Nitrogen oxide and bromine combine to form nitrosyl bromide, NOBr.
2NO(g) + Br2(g) 2NOBr(g)

In a 5.0 liter reactor at equilibrium at a constant temperature, it was determined there was 0.45 mol NO, 0.17 mol Br and 1.32 mol NOBr. What is the value of Kc at this temperature?



a. 0.0116
b. 86.2
c. 253
d. 0.00395
e. 22.7


Answer: c. 253

Consider the following reversible reaction. In a 3.00-liter container, the following amounts are found in equilibrium at 400°C: 0.0420 mole N2, 0.516 mole H2, and 0.0357 mole NH3. Evaluate Kc. N2(g) + 3H2(g) 2NH3(g)

Consider the following reversible reaction. In a 3.00-liter container, the following amounts are found in equilibrium at 400°C: 0.0420 mole N2, 0.516 mole H2, and 0.0357 mole NH3. Evaluate Kc.
N2(g) + 3H2(g) 2NH3(g)


a. 0.202
b. 1.99
c. 16.0
d. 4.94
e. 0.503


Answer: b. 1.99

For a reversible reaction with a one-step mechanism, A B , the rate of the forward reaction is ratef = 3.2 × 10−6 s−1 [A] and the rate of the reverse reaction is rater = 4.6 × 10−4 s−1 [B]. What is the value of Kc for this reaction?

For a reversible reaction with a one-step mechanism, A B , the rate of the forward reaction is ratef = 3.2 × 10−6 s−1 [A] and the rate of the reverse reaction is rater = 4.6 × 10−4 s−1 [B]. What is the value of Kc for this reaction?



a. 2.5 × 10−11
b. 7.0 × 109
c. 7.0 × 10−3
d. 1.4 × 102
e. 1.5 × 10−9


Answer: c. 7.0 × 10−3

When the system A + B C + D is at equilibrium,

When the system A + B C + D is at equilibrium,



a. the forward reaction has stopped.
b. the reverse reaction has stopped.
c. both the forward and the reverse reactions have stopped.
d. neither the forward nor the reverse reaction has stopped.
e. the sum of the concentrations of A and B must equal the sum of the concentrations of C
and D.


Answer: d. neither the forward nor the reverse reaction has stopped.

Which of the following is the best definition of chemical equilibrium?

Which of the following is the best definition of chemical equilibrium?



a. A condition where the forward and reverse reaction rates of a reversible reaction are equal
and constant.
b. There are equal amounts of reactants and products.
c. The forward and reverse reaction rates have stopped.
d. The product concentrations are larger than reactant concentrations.
e. The reactant concentrations are larger than product concentrations.


Answer: a. A condition where the forward and reverse reaction rates of a reversible reaction are equal
and constant.

Which of the statements concerning equilibrium is false?

Which of the statements concerning equilibrium is false?



a. A system that is disturbed from an equilibrium condition responds in a manner to restore
equilibrium.
b. Equilibrium in molecular systems is dynamic, with two opposing processes balancing one
another.
c. The value of the equilibrium constant for a given reaction mixture is the same regardless
of the direction from which equilibrium was attained.
d. A system moves spontaneously toward a state of equilibrium.
e. The equilibrium constant usually is independent of temperature.


Answer: e. The equilibrium constant usually is independent of temperature.

How would an increase in temperature affect the following equilibrium?

How would an increase in temperature affect the following equilibrium?

H2O(l ) <--> H2(g) + 1/2O2(g) ΔH° = 482.0 kJ/mol

a. More product would form and K would increase.

b. More product would form but K would remain constant.

c. K would be unaffected by a temperature change.

d. More reactants would form but K would remain constant.

e. More reactants would form and K would decrease.


Answer: a. More product would form and K would increase.

The forward rate constant, kf, and reverse rate constant, kr, for a chemical reaction are not equal. Which of the following must be true?

The forward rate constant, kf, and reverse rate constant, kr, for a chemical reaction are not equal. Which of the following must be true?


a. The reaction will be unable to achieve equilibrium.

b. kf and kr will become equal as equilibrium is approached, owing to concentration changes.

c. kf and kr will become equal as equilibrium is approached, owing to temperature changes.

d. kf and kr will remain unequal but the rates will become equal, owing to concentration changes.

e. kf and kr will remain unequal but the rates will become equal, owing to temperature changes.


Answer: d. kf and kr will remain unequal but the rates will become equal, owing to concentration changes.

Which of the following is true for a chemical reaction at equilibrium?

Which of the following is true for a chemical reaction at equilibrium?


a. Only the forward reaction stops.

b. Only the reverse reaction stops.

c. Both the forward and reverse reactions stop.

d. The rate constants for the forward and reverse reactions are equal.

e. The rates of the forward and reverse reactions are equal.


Answer: e. The rates of the forward and reverse reactions are equal.

The equilibrium constant for the formation of calcium carbonate from the ions in solution is 2.2 × 108 according to the reaction:

The equilibrium constant for the formation of calcium carbonate from the ions in solution is
2.2 × 108 according to the reaction:

Ca^2+(aq) + CO3^2-(aq) <---> CaCO3(s)
What is the value of the equilibrium constant for the reverse of this reaction?

a. the same, 2.2 × 108

b. −2.2 × 108

c. 2.2 × 10−8 x

d. 4.5 × 10−9 x

e. 4.5 × 109


Answer: 2.2 X 10^-8(wrong)

Given the following reactions and associated equilibrium constants

Given the following reactions and associated equilibrium constants

SO2(g) + 1/2O2(g) <--> SO3(g)
K1 = 3.1
NO2 <--> NO(g) +1/2O2(g)
K2 = 4.5
what is the equilibrium constant for the following reaction?
SO3(g) + NO(g) <--> SO2(g) + NO2(g) Knew = ?

a. 1.45

b. 7.17 × 10-2

c. 14.0

d. 6.89 × 10-1

e. 163


Answer: 6.89x10^-1(wrong)

In the Reaction, Initial, Change, Equilibrium (RICE) table started for calculating equilibrium concentrations of the reaction shown, the terms in the "equilibrium" row are ________

In the Reaction, Initial, Change, Equilibrium (RICE) table started for calculating equilibrium concentrations of the reaction shown, the terms in the "equilibrium" row are ________


M3^+ + 3L <--> ML3^3+
R [M3+] [L] [ML33+]
I 0.15 M 0.40 M 0 M
C
E ________ ________ ________


a. 0.15 − x, 0.40 − 3x, +x.

b. −x, −3x, +x.

c. 0.15 − x, 0.40 − x, +x.

d. 0.15, 0.40, +x.

e. 0.15 + x, 0.40 + 3x, −x.


Answer: c. 0.15 − x, 0.40 − 3x, +x.

If the reaction quotient Q has a larger value than the related equilibrium constant, K, ________

If the reaction quotient Q has a larger value than the related equilibrium constant, K, ________


a. the reaction is at equilibrium.

b. the reaction will continue to make more products.

c. the reaction will consume products and make reactants.

d. the reaction will release heat to achieve equilibrium.

e. the value of K will increase until it is equal to Q.


Answer: c. the reaction will consume products and make reactants.

The reaction of bromine gas with chlorine gas, shown here, has a Kp value of 7.20. If a closed vessel was charged with the two reactants, each at an initial partial pressure of 0.500 atm, what would be the equilibrium partial pressure of BrCl(g)?

The reaction of bromine gas with chlorine gas, shown here, has a Kp value of 7.20. If a closed vessel was charged with the two reactants, each at an initial partial pressure of 0.500 atm, what would be the equilibrium partial pressure of BrCl(g)?


Br2(g) + Cl2(g) --> 2 BrCl(g)

a. 1.9 atm

b. 1.4 atm

c. 0.84 atm

d. 0.29 atm

e. 0.57 atm


Answer: e. 0.57 atm

Identify whether or not perturbations A-D will affect the equilibrium concentrations of reactants and products in a gas-phase endothermic chemical reaction that involves one or more gases. If all have an effect on the equilibrium concentrations, select response E. Otherwise, identify the one that does not affect the equilibrium concentrations.

Identify whether or not perturbations A-D will affect the equilibrium concentrations of reactants and products in a gas-phase endothermic chemical reaction that involves one or more gases. If all have an effect on the equilibrium concentrations, select response E. Otherwise, identify the one that does not affect the equilibrium concentrations.


a. adding reactants to a gas or solution reaction

b. removing products from a gas or solution reaction

c. decreasing the temperature

d. increasing pressure by adding an inert gas to a reaction in the gas phase

e. All of the above are perturbations to chemical equilibrium.


Answer: d. increasing pressure by adding an inert gas to a reaction in the gas phase

Which of the following is TRUE regarding fondaparinux?

Which of the following is TRUE regarding fondaparinux?



A) It can always be used for the treatment of VTE
B) It was the highest peak concentration of all the anti-Xa drugs
C) It should not be used as monotherapy in the treatment of STEM
D) It is contraindicated in fibrinolysis


Answer: It should not be used as monotherapy in the treatment of STEM

An 82 year old male was seen today in clinic and diagnosed with atrial fibrillation. He weighs 70Kg, has a SCr=2.1mg/dL and no drug allergies. The patient's PCP wants to prescribe Eliquis (apixaban). Which dose is CORRECT?

An 82 year old male was seen today in clinic and diagnosed with atrial fibrillation. He weighs 70Kg, has a SCr=2.1mg/dL and no drug allergies. The patient's PCP wants to prescribe Eliquis (apixaban). Which dose is CORRECT?


A) 5mg twice daily
B) 2.5mg twice daily
C) 5mg once daily
D) 2.5mg once daily


Answer: 2.5mg twice daily

Which of the following is CORRECT about clopidogrel?

Which of the following is CORRECT about clopidogrel?


A) Clopidogrel is metabolized by CYP3A4
B) Clopidogrel is a prodrug
C) Clopidogrel is reversibly bound
D) Clopidogrel maintenance dose is 90mg twice daily


Answer: Clopidogrel is a prodrug

Which is not a candidate for ICD?

Which is not a candidate for ICD?


A) class II/III with LVEF <35%, post 40 days MI
B) class I LVEF <30%, post 40 days MI
C) secondary prevention and class IV HF


Answer: secondary prevention and class IV HF

If a patient has SVT what should be done first?

If a patient has SVT what should be done first?


A) vasovagal maneuvers
B) IV BBs or non-DHP CCBs
C) synchronized cardioversion


Answer: vasovagal manuevers

Which drugs block Ca+?

Which drugs block Ca+?


A) lidocaine, flecainide
B) amiodarone, sotalol, dofetilide, dronedarone
C) diltiazem, verapamil


Answer: diltiazem, verapamil

Which drugs block K+?

Which drugs block K+?


A) lidocaine, flecainide
B) amiodarone, sotalol, dofetilide, dronedarone
C) diltiazem, verapamil


Answer: amiodarone, sotalol, dofetilide, dronedarone

Which drugs block Na+?

Which drugs block Na+?


A) lidocaine, flecainide
B) amiodarone, sotalol, dofetilide, dronedarone
C) diltiazem, verapamil


Answer: lidocaine, flecainide

At what QTc should QT-prolong drugs be avoided?

At what QTc should QT-prolong drugs be avoided?


A) >450 (M) and >460 (F)
B) >440 (M) and >450 (F)
C) >430 (M) and >440 (F)
D) >420 (M) and >430 (F)


Answer: >450 (M) and >460 (F)

QRS complex is

QRS complex is


A) atrial depolarization
B) ventricular depolarization
C) ventricular repolarization


Answer: ventricular depolarization

T wave is

T wave is


A) atrial depolarization
B) ventricular depolarization
C) ventricular repolarization


Answer: ventricular repolarization

P wave is

P wave is


A) atrial depolarization
B) ventricular depolarization
C) ventricular repolarization


Answer: atrial depolarization

VKORC1 1639 AA requires

VKORC1 1639 AA requires


A) dose increase
B) dose decrease


Answer: dose decrease

Which is not an exclusion for outpatient?

Which is not an exclusion for outpatient?


A) dialysis
B) active bleeding 1 mo ago
C) major surgery within past 2w
D) decompensation


Answer: active bleeding 1 mo ago

What is the Dabigatran dose for hip prophylaxis?

What is the Dabigatran dose for hip prophylaxis?



A) 150 mg BID
B) 75 mg BID
C) 110 mg day of sx, then 220 mg for 28-35 days


Answer: 110 mg day of sx, then 220 mg for 28-35 days

What is the Rivaroxaban dose for VTE treatment?

What is the Rivaroxaban dose for VTE treatment?


A) 20 mg daily
B) 15 mg daily
C) 15 mg BID for 21 days, then 20 mg
D) 10 mg for 35 days


Answer: 5 mg BID for 21 days, then 20 mg

What is the Edoxaban dose for VTE treatment?

What is the Edoxaban dose for VTE treatment?



A) 60 mg daily
B) 60 mg daily after 5-10 days of parenteral


Answer: 60 mg daily after 5-10 days of parenteral (CrCl 15-30 or <60 kg= 30 mg)

What is the Apixaban dose for stroke prevention?

What is the Apixaban dose for stroke prevention?


A) 5 mg BID
B) 10 mg BID x 7 days, then 5 mg BID
C) 2.5 mg BID


Answer: 5 mg BID (2.5 if age>80, weight <60, SCr>1.5)

Warfarin can be changed to DOAC as soon as:

Warfarin can be changed to DOAC as soon as:


A) INR <4
B) INR <1
C) INR <3
D) INR <2


Answer: INR <2 (exception: riva <3 and edoxa <2.5)

What is not a contraindication to ARNI?

What is not a contraindication to ARNI?


A) class II-III
B) angioedema
C) combined with ACEI
D) aliskiren with diabetes


Answer: class II-III

Which BB cannot be used in HFrEF?

Which BB cannot be used in HFrEF?


A) bisoprolol
B) metoprolol succinate
C) metoprolol tartrate
D) carvedilol


Answer: metoprolol tartrate

Every HF patient should ideally be started on:

Every HF patient should ideally be started on:


A) ACEI/ARB and BB
B) BB and diuretic
C) diuretic and ACEI/ARB
D) digoxin and ACEI/ARB


Answer: ACEI/ARB and BB

Which 2 drug classes only improve HF symptoms?

Which 2 drug classes only improve HF symptoms?


A) CCBs and digoxin
B) digoxin and diuretics
C) diuretics and ARNI
D) ivabradine and diuretics


Answer: digoxin and diuretics

What is not a compensation in HF?

What is not a compensation in HF?


A) increased preload (RAAS)
B) increased contractility and tachycardia (SNS)
C) vasodilation (SNS/ANG II)
D) ventricular hypertrophy (ALDO/ANGII/endothelin)


Answer: vasodilation (SNS/ANG II)

HFpEF is:

HFpEF is:


A) systole= contracting/pumping problem
B) diastole=relaxing/filling problem
C) systole= relaxing/filling problem
D) diastole problem= contracting/pumping problem


Answer: diastole=relaxing/filling problem

A patient post-ACS is discharged home with:

A patient post-ACS is discharged home with:


A) aspirin, P2Y12, BB, high intensity statin, NTG
B) acetaminophen, P2Y12, CCB, mod intensity statin, NTG
C) aspirin, P2Y12, BB, mod intensity statin, NTG
D) acetaminophen, P2Y12, CCB, low intensity statin, NTG


Answer: aspirin, P2Y12, BB, high intensity statin, NTG

What does MONA stand for?

What does MONA stand for?


A) morphine, oxycontin, nifedipine, acetaminophen
B) metoprolol, oxycontin, nifedipine, aspirin
C) morphine, oxygen, nitroglycerin, aspirin
D) metoprolol, oxygen, nitroglycerin, acetaminophen


Answer: morphine, oxygen, nitroglycerin, aspirin

Which DTIs are irreversible and bivalent?

Which DTIs are irreversible and bivalent?


A) lepirudin and argatroban
B) lepirudin and desirudin
C) dabigatran and desirudin
D) dabigatran and argatroban


Answer: lepirudin and desirudin

Which P2Y12 inhibitor are reversible?

Which P2Y12 inhibitor are reversible?


A) clopidogrel and prasugrel
B) ticagrelor and prasugrel
C) clopidogrel and cangrelor
D) ticagrelor and cangrelor


Answer: ticagrelor and cangrelor

What is the metabolism of bivalrudin?

What is the metabolism of bivalrudin?


A) plasma proteases
B) acid hydrolases
C) gluconeogensis
D) lipolysis


Answer: plasma proteases

Which drug is not a DTI?

Which drug is not a DTI?


A) bivalrudin
B) argatroban
C) tirofiban
D) dabigatran


Answer: tirofiban

Gold standard of diagnosis of IHD

Gold standard of diagnosis of IHD


A) stress test
B) ECG
C) echocardiogram
D) coronary angiography


Answer: stress test
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