Question 1

Which equilibrium below is homogeneous?

Accepted Answer

A) CaSO4(s)⇌ Ca2+(aq)+ SO42-(aq) 
B) 2 H2O2(l)⇌ 2 H2O(l)+ O2(g) 
C) NH4NO3(s)⇌ N2O(g)+ 2 H2O(g) 
D) 2 CO(g)+ O2(g)⇌ 2 CO2(g) 
A) CaSO4(s)⇌ Ca2+(aq)+ SO42-(aq) 
B) 2 H2O2(l)⇌ 2 H2O(l)+ O2(g) 
C) NH4NO3(s)⇌ N2O(g)+ 2 H2O(g) 
D) 2 CO(g)+ O2(g)⇌ 2 CO2(g)

Question 2

The equilibrium constant,Kp,equals 3.40 for the isomerization reaction: cis-2-butene ⇌ trans-2-butene.
If a flask initially contains 0.250 atm of cis-2-butene and 0.205 atm of trans-2-butene,what is the equilibrium pressure of each gas?

Accepted Answer

A) P(cis-2-butene)= 0.0603 atm and P(trans-2-butene)= 0.205 atm 
B) P(cis-2-butene)= 0.0431 atm and P(trans-2-butene)= 0.147 atm 
C) P(cis-2-butene)= 0.0735 atm and P(trans-2-butene)= 0.250 atm 
D) P(cis-2-butene)= 0.103 atm and P(trans-2-butene)= 0.352 atm 
A) P(cis-2-butene)= 0.0603 atm and P(trans-2-butene)= 0.205 atm 
B) P(cis-2-butene)= 0.0431 atm and P(trans-2-butene)= 0.147 atm 
C) P(cis-2-butene)= 0.0735 atm and P(trans-2-butene)= 0.250 atm 
D) P(cis-2-butene)= 0.103 atm and P(trans-2-butene)= 0.352 atm

Question 3

Kc = 57.0 at 700 K for the reaction shown below.
H2(g)+ I2(g)⇌ 2 HI(g)
If [H2(g)] = [I2(g)] = 0.200 M at equilibrium,the molar concentration [HI((g)] = ________ at equilibrium.

Accepted Answer

Question 4

The following pictures represent the initial state and the equilibrium state for the gaseous state reaction of AS1U1B12S1U1B0 molecules (shaded spheres)with B atoms (unshaded spheres)to give AB molecules.  
-What is the best balanced chemical equation for the reaction?

Accepted Answer

A) A2 + B ⇌ A2B 
B) A2 + 2 B ⇌ A2B2 
C) A2 + 2 B ⇌ 2 AB 
D) 6 A2 + 9 B ⇌ 3 A2 + 3B + 6 AB 
A) A2 + B ⇌ A2B 
B) A2 + 2 B ⇌ A2B2 
C) A2 + 2 B ⇌ 2 AB 
D) 6 A2 + 9 B ⇌ 3 A2 + 3B + 6 AB

Question 5

Which of the following changes in reaction conditions will alter the composition of an equilibrium mixture of gases for a reaction having unequal moles of gaseous products and gaseous reactants?

Accepted Answer

A) adding of products 
B) decreasing the volume 
C) increasing the temperature 
D) All of these will alter the equilibrium concentrations. 
A) adding of products 
B) decreasing the volume 
C) increasing the temperature 
D) All of these will alter the equilibrium concentrations.

Question 6

A mixture of carbon monoxide,hydrogen,and methanol is at equilibrium.The balanced chemical equation is: CO(g)+ 2 H2(g)⇌ CH3OH(g).At 250°C,the mixture contains 0.0960 M CO,0.191 M H2,and 0.150 M CH3OH.What is the value for Kc?

Accepted Answer

A) 2.33 × 10-2 
B) 0.244 
C) 4.09 
D) 42.8 
A) 2.33 × 10-2 
B) 0.244 
C) 4.09 
D) 42.8

Question 7

If Kc = 2.0 × 1033 at 25°C,for the following reaction: H2(g)+ Cl2(g)⇌ 2 HCl(g),then find Kp at the same temperature.

Accepted Answer

A) 8.2 × 1031 
B) 9.7× 1032 
C) 2.0 × 1033 
D) 4.9 × 1034 
A) 8.2 × 1031 
B) 9.7× 1032 
C) 2.0 × 1033 
D) 4.9 × 1034

Question 8

The equilibrium constant,Kp,equals 3.40 at 25°C for the isomerization reaction: cis-2-butene ⇌ trans-2-butene.
If a flask initially contains 3.00 atm of each gas,in what direction will the system shift to reach equilibrium?

Accepted Answer

A) It will shift left. 
B) It will shift right. 
C) The system is already at equilibrium. 
D) The system is not at equilibrium and will remain in an unequilibrated state. 
A) It will shift left. 
B) It will shift right. 
C) The system is already at equilibrium. 
D) The system is not at equilibrium and will remain in an unequilibrated state.

Question 9

Kc = 1.2 × 10-42 at 500 K for the reaction shown below.
H2(g)⇌ 2 H(g)
If [H2] = 1 × 10-2 M and [H] = 1.2 × 10-22 M,in order to achieve equilibrium a net reaction must occur from ________ to ________ until Qc = ________.

Accepted Answer

Question 10

The reaction CaCO3(s)⇌ CaO(s)+ O2(g)is endothermic at 298 K.The effect of increasing the temperature of the system at equilibrium will ________ (decrease,increase,have no effect on)the total quantity of CaCO3 once equilibrium is reestablished.

Accepted Answer

Question 11

In a reversible reaction,when the rate of the forward reaction equals the rate of the reverse reaction,the reaction is at ________.

Accepted Answer

The answer of In a reversible reaction,when the rate of...

Question 12

Picture (1)represents an equilibrium mixture of solid CaCOS1U1B13S1U1B0,solid CaO,and gaseous COS1U1B12S1U1B0,obtained as a result of the endothermic decomposition of CaCOS1U1B13S1U1B0.  
-Which picture (2)-(4)represents the equilibrium mixture when a catalyst is added?

Accepted Answer

A) picture (2) 
B) picture (3) 
C) picture (4) 
D) All of these 
A) picture (2) 
B) picture (3) 
C) picture (4) 
D) All of these

Question 13

The reaction AS1U1B12S1U1B0 + BS1U1B12 S1U1B0⇌ 2AB has an equilibrium constant KS1U1B1cS1U1B0 = 1.8.The following pictures represent reaction mixtures that contain AS1U1B12S1U1B0 molecules (shaded)and BS1U1B12S1U1B0 molecules (unshaded),and AB molecules.  
-Which nonequilibrium mixtures will react in the reverse direction to reach equilibrium?

Accepted Answer

A) reaction mixtures (1)and (2) 
B) reaction mixtures (1)and (4) 
C) reaction mixtures (2)and (3) 
D) reaction mixtures (3)and (4) 
A) reaction mixtures (1)and (2) 
B) reaction mixtures (1)and (4) 
C) reaction mixtures (2)and (3) 
D) reaction mixtures (3)and (4)

Question 14

Ammonium bromide is a crystalline solid that decomposes endothermically when heated: NH4Br(s)⇌ NH3(g)+ HBr(g).When solid NH4Br is added to an evacuated flask at 300°C,which change in reaction conditions below will cause the equilibrium to shift to the right?

Accepted Answer

A) add more HBr  
B) add more NH4Br 
C) decrease the temperature 
D) decrease the pressure 
A) add more HBr  
B) add more NH4Br 
C) decrease the temperature 
D) decrease the pressure

Question 15

A reaction in which reactants form products in the forward reaction and products simultaneously form reactants in the reverse reaction is said to be ________.

Accepted Answer

The answer of A reaction in which reactants form products...

Question 16

Which of the following statements is false regarding the equilibrium constant,Kc?

Accepted Answer

A) Kc for a reaction at a particular temperature always has the same value. 
B) Kc for the reverse reaction is the negative of Kc for the forward reaction. 
C) The numerical value of Kc depends on the form of the balanced equation. 
D) When quoting Kc it is customary to omit units. 
A) Kc for a reaction at a particular temperature always has the same value. 
B) Kc for the reverse reaction is the negative of Kc for the forward reaction. 
C) The numerical value of Kc depends on the form of the balanced equation. 
D) When quoting Kc it is customary to omit units.

Question 17

The following picture represents the equilibrium state for the reaction A2 + B2 ⇌ 2AB.What is the relationship between the rate constant for the forward reaction,kf,and the rate constant for the reverse reaction kr?

Accepted Answer

A) kf r 
B) kf = kr = 0 
C) kf = kr 
D) kf > kr 
A) kf r 
B) kf = kr = 0 
C) kf = kr 
D) kf > kr

Question 18

Kp = 1.5 × 103 at 400°C for the reaction 2 NH3(g)⇌ N2(g)+ 3 H2(g).What is the value of Kp for the reaction: 2 N2(g)+ 6 H2(g)⇌ 4 NH3(g)?

Accepted Answer

A) 4.4 × 10-7 
B) 3.3 × 10-4 
C) 6.7 × 10-4 
D) 2.3 × 106 
A) 4.4 × 10-7 
B) 3.3 × 10-4 
C) 6.7 × 10-4 
D) 2.3 × 106

Question 19

Iron oxide ores are reduced to iron metal by exothermic reaction with carbon monoxide:   Which of the following changes in condition will cause the equilibrium to shift to the right?

Accepted Answer

A) remove FeO 
B) add CO 
C) add CO2 
D) raise the temperature 
A) remove FeO 
B) add CO 
C) add CO2 
D) raise the temperature

Question 20

For the reaction shown below,which change in conditions made to the system at equilibrium will result in a net reaction to the right to form more product? C(s)+ 2 H2(g)⇌ CH4(g)ΔH° = -74.8 kJ

Accepted Answer

A) removing C 
B) increasing the volume 
C) increasing the pressure 
D) removing H2 
A) removing C 
B) increasing the volume 
C) increasing the pressure 
D) removing H2

Exam 14: Chemical Equilibrium

Which equilibrium below is homogeneous?

The equilibrium constant,Kp,equals 3.40 for the isomerization reaction: cis-2-butene ⇌ trans-2-butene. If a flask initially contains 0.250 atm of cis-2-butene and 0.205 atm of trans-2-butene,what is the equilibrium pressure of each gas?

Kc = 57.0 at 700 K for the reaction shown below. H2(g)+ I2(g)⇌ 2 HI(g) If [H2(g)] = [I2(g)] = 0.200 M at equilibrium,the molar concentration [HI((g)] = ________ at equilibrium.

The following pictures represent the initial state and the equilibrium state for the gaseous state reaction of A2 molecules (shaded spheres)with B atoms (unshaded spheres)to give AB molecules. -What is the best balanced chemical equation for the reaction?

Which of the following changes in reaction conditions will alter the composition of an equilibrium mixture of gases for a reaction having unequal moles of gaseous products and gaseous reactants?

A mixture of carbon monoxide,hydrogen,and methanol is at equilibrium.The balanced chemical equation is: CO(g)+ 2 H2(g)⇌ CH3OH(g).At 250°C,the mixture contains 0.0960 M CO,0.191 M H2,and 0.150 M CH3OH.What is the value for Kc?

If Kc = 2.0 × 1033 at 25°C,for the following reaction: H2(g)+ Cl2(g)⇌ 2 HCl(g),then find Kp at the same temperature.

The equilibrium constant,Kp,equals 3.40 at 25°C for the isomerization reaction: cis-2-butene ⇌ trans-2-butene. If a flask initially contains 3.00 atm of each gas,in what direction will the system shift to reach equilibrium?

Kc = 1.2 × 10-42 at 500 K for the reaction shown below. H2(g)⇌ 2 H(g) If [H2] = 1 × 10-2 M and [H] = 1.2 × 10-22 M,in order to achieve equilibrium a net reaction must occur from ________ to ________ until Qc = ________.

The reaction CaCO3(s)⇌ CaO(s)+ O2(g)is endothermic at 298 K.The effect of increasing the temperature of the system at equilibrium will ________ (decrease,increase,have no effect on)the total quantity of CaCO3 once equilibrium is reestablished.

In a reversible reaction,when the rate of the forward reaction equals the rate of the reverse reaction,the reaction is at ________.

Picture (1)represents an equilibrium mixture of solid CaCO3,solid CaO,and gaseous CO2,obtained as a result of the endothermic decomposition of CaCO3. -Which picture (2)-(4)represents the equilibrium mixture when a catalyst is added?

The reaction A2 + B2 ⇌ 2AB has an equilibrium constant Kc = 1.8.The following pictures represent reaction mixtures that contain A2 molecules (shaded)and B2 molecules (unshaded),and AB molecules. -Which nonequilibrium mixtures will react in the reverse direction to reach equilibrium?

Ammonium bromide is a crystalline solid that decomposes endothermically when heated: NH4Br(s)⇌ NH3(g)+ HBr(g).When solid NH4Br is added to an evacuated flask at 300°C,which change in reaction conditions below will cause the equilibrium to shift to the right?

A reaction in which reactants form products in the forward reaction and products simultaneously form reactants in the reverse reaction is said to be ________.

Which of the following statements is false regarding the equilibrium constant,Kc?

The following picture represents the equilibrium state for the reaction A2 + B2 ⇌ 2AB.What is the relationship between the rate constant for the forward reaction,kf,and the rate constant for the reverse reaction kr?

Kp = 1.5 × 103 at 400°C for the reaction 2 NH3(g)⇌ N2(g)+ 3 H2(g).What is the value of Kp for the reaction: 2 N2(g)+ 6 H2(g)⇌ 4 NH3(g)?

Iron oxide ores are reduced to iron metal by exothermic reaction with carbon monoxide: Which of the following changes in condition will cause the equilibrium to shift to the right?

For the reaction shown below,which change in conditions made to the system at equilibrium will result in a net reaction to the right to form more product? C(s)+ 2 H2(g)⇌ CH4(g)ΔH° = -74.8 kJ

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The equilibrium constant,K_p,equals 3.40 for the isomerization reaction: cis-2-butene ⇌ trans-2-butene. If a flask initially contains 0.250 atm of cis-2-butene and 0.205 atm of trans-2-butene,what is the equilibrium pressure of each gas?

K_c = 57.0at 700 K for the reaction shown below. H₂(g)+ I₂(g)⇌ 2 HI(g) If [H₂(g)] = [I₂(g)] = 0.200 M at equilibrium,the molar concentration [HI((g)] = ________ at equilibrium.

The following pictures represent the initial state and the equilibrium state for the gaseous state reaction of A₂ molecules (shaded spheres)with B atoms (unshaded spheres)to give AB molecules. -What is the best balanced chemical equation for the reaction?

A mixture of carbon monoxide,hydrogen,and methanol is at equilibrium.The balanced chemical equation is: CO(g)+ 2 H₂(g)⇌ CH₃OH(g).At 250°C,the mixture contains 0.0960 M CO,0.191 M H₂,and 0.150 M CH₃OH.What is the value for K_c?

If K_c = 2.0 × 10³³ at 25°C,for the following reaction: H₂(g)+ Cl₂(g)⇌ 2 HCl(g),then find K_p at the same temperature.

The equilibrium constant,K_p,equals 3.40 at 25°C for the isomerization reaction: cis-2-butene ⇌ trans-2-butene. If a flask initially contains 3.00 atm of each gas,in what direction will the system shift to reach equilibrium?

K_c = 1.2 × 10^-42at 500 K for the reaction shown below. H₂(g)⇌ 2 H(g) If [H₂] = 1 × 10^-2 M and [H] = 1.2 × 10^-22 M,in order to achieve equilibrium a net reaction must occur from to until Q_c = ________.

The reaction CaCO₃(s)⇌ CaO(s)+ O₂(g)is endothermic at 298 K.The effect of increasing the temperature of the system at equilibrium will ________ (decrease,increase,have no effect on)the total quantity of CaCO₃ once equilibrium is reestablished.

Picture (1)represents an equilibrium mixture of solid CaCO₃,solid CaO,and gaseous CO₂,obtained as a result of the endothermic decomposition of CaCO₃. -Which picture (2)-(4)represents the equilibrium mixture when a catalyst is added?

The reaction A₂ + B₂⇌ 2AB has an equilibrium constant K_c = 1.8.The following pictures represent reaction mixtures that contain A₂ molecules (shaded)and B₂ molecules (unshaded),and AB molecules. -Which nonequilibrium mixtures will react in the reverse direction to reach equilibrium?

Ammonium bromide is a crystalline solid that decomposes endothermically when heated: NH₄Br(s)⇌ NH₃(g)+ HBr(g).When solid NH₄Br is added to an evacuated flask at 300°C,which change in reaction conditions below will cause the equilibrium to shift to the right?

Which of the following statements is false regarding the equilibrium constant,K_c?

The following picture represents the equilibrium state for the reaction A₂ + B₂ ⇌ 2AB.What is the relationship between the rate constant for the forward reaction,k_f,and the rate constant for the reverse reaction k_r?

K_p = 1.5 × 10³ at 400°C for the reaction 2 NH₃(g)⇌ N₂(g)+ 3 H₂(g).What is the value of K_p for the reaction: 2 N₂(g)+ 6 H₂(g)⇌ 4 NH₃(g)?

For the reaction shown below,which change in conditions made to the system at equilibrium will result in a net reaction to the right to form more product? C(s)+ 2 H₂(g)⇌ CH₄(g)ΔH° = -74.8 kJ