Question 1

Which of the following expressions for K is correct for the reaction given below? HF(aq)+ H2O(   )   F-(aq)+ H3O+(aq)

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 2

The symbol Q is called the ________.

Accepted Answer

The answer of The symbol Q is called the ________....

Question 3

When 0.20 mole HF is dissolved in water to a volume of 1.00 L,5.8% of the HF dissociates to form F-(aq).What is the equilibrium constant for the reaction? HF(aq)+ H2O(   )   F-(aq)+ H3O+(aq)

Accepted Answer

A)  1.3 × 10-4 
B)  7.1 × 10-4 
C)  1.2 × 10-2 
D)  1.7 × 10-2 
E)  6.2 × 10-2 
A)  1.3 × 10-4 
B)  7.1 × 10-4 
C)  1.2 × 10-2 
D)  1.7 × 10-2 
E)  6.2 × 10-2

Question 4

A 3.50-mol sample of HI is placed in a 1.00-L vessel at 460°C,and the reaction system is allowed to come to equilibrium.The HI partially decomposes,forming 0.266 mol H2 and 0.266 mol I2 at equilibrium.What is the equilibrium constant Kc for the following reaction at 460°C? ½ H2(g)+ ½ I2(g)   HI(g)

Accepted Answer

A)  1.23 × 102 
B)  8.10 × 10-3 
C)  2.40 × 10-2 
D)  11.1 
E)  6.45 
A)  1.23 × 102 
B)  8.10 × 10-3 
C)  2.40 × 10-2 
D)  11.1 
E)  6.45

Question 5

The equilibrium constant,K,is always the same within experimental error for all experiments done at a given temperature.

Accepted Answer

A) True 
 B)False

Question 6

A 10.0 g sample of solid NH4Cl is heated in a 5.00 L container to 900 °C.At equilibrium,the pressure of NH3(g)is 1.17 atm.Calculate the equilibrium constant,Kp,for the reaction below. NH4Cl(s)   NH3(g)+ HCl(g)

Accepted Answer

A)  1.37 
B)  4.93 
C)  1.17 
D)  2.34 
E)  None of these 
A)  1.37 
B)  4.93 
C)  1.17 
D)  2.34 
E)  None of these

Question 7

The thermochemical equation for the formation of ammonia from elemental nitrogen and hydrogen is as follows. N2(g)+ 3 H2(g)   2 NH3(g)
ΔH = -92.2 kJ
Given a system that is initially at equilibrium,which of the following actions cause the reaction to proceed to the left?

Accepted Answer

A)  adding N2(g) 
B)  removing NH3(g) 
C)  adding a catalyst 
D)  decreasing the temperature 
E)  removing H2(g) 
A)  adding N2(g) 
B)  removing NH3(g) 
C)  adding a catalyst 
D)  decreasing the temperature 
E)  removing H2(g)

Question 8

Consider the following equilibrium: C2H6(g)+ C5H12(g)   CH4(g)+ C6H14(g); Kp = 9.57 at 500 K
Suppose 22.7 g each of CH4,C2H6,C5H12,and C6H14 are placed in a 35.0-L reaction vessel at 500 K.Which of the following statements is correct?

Accepted Answer

A)  Because Qc c,more products will be formed. 
B)  Because Qc = 1,the system is at equilibrium. 
C)  Because Qc = 1,more products will be formed. 
D)  Because Qc = 1,more reactants will be formed. 
E)  Because Qc > Kc,more reactants will be formed. 
A)  Because Qc c,more products will be formed. 
B)  Because Qc = 1,the system is at equilibrium. 
C)  Because Qc = 1,more products will be formed. 
D)  Because Qc = 1,more reactants will be formed. 
E)  Because Qc > Kc,more reactants will be formed.

Question 9

A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature. 3H2 + N2   2NH3
An analysis of the mixture at equilibrium revealed 2.1 mol N2,2.8 mol H2,and 1.8 mol NH3.How many moles of H2 were present at the beginning of the reaction?

Accepted Answer

A)  2.8 
B)  4.2 
C)  4.6 
D)  5.5 
E)  4.0 
A)  2.8 
B)  4.2 
C)  4.6 
D)  5.5 
E)  4.0

Question 10

Nitrogen trifluoride decomposes at to form nitrogen and fluorine gases according to the following equation: 2NF3(g)   N2(g)+ 3F2(g)
2)50-L reaction vessel is initially charged with 1.22 mol of NF3 and allowed to come to equilibrium at 800 K.Once equilibrium is established,the reaction vessel is found to contain 0.0194 mol of N2.What is the value of Kp at this temperature? (R = 0.0821 L⋅atm/mol⋅K)

Accepted Answer

A)  2.68 × 10-6 
B)  1.91 × 10-3 
C)  1.79 × 10-3 
D)  2.77 × 10-6 
E)  4.43 × 10-7 
A)  2.68 × 10-6 
B)  1.91 × 10-3 
C)  1.79 × 10-3 
D)  2.77 × 10-6 
E)  4.43 × 10-7

Question 11

When the pressure of an equilibrium mixture of SO2,O2,and SO3 is doubled at constant temperature,what the effect on Kp? 2SO2(g)+ O2(g)   2SO3(g)

Accepted Answer

A)  Kp is halved. 
B)  Kp is doubled. 
C)  Kp is unchanged. 
D)  Kp is tripled. 
E)  Kp is decreased by a third. 
A)  Kp is halved. 
B)  Kp is doubled. 
C)  Kp is unchanged. 
D)  Kp is tripled. 
E)  Kp is decreased by a third.

Question 12

If Kc = 0.124 for A2 + 2B   2AB,what is the value of Kc for the reaction 4AB   2A2 + 4B?

Accepted Answer

A)  0.124 
B)  0.248 
C)  65.0 
D)  -0.124 
E)  4.03 
A)  0.124 
B)  0.248 
C)  65.0 
D)  -0.124 
E)  4.03

Question 13

Which of the following is the correct balanced equation for the equilibrium constant expression given below?

Accepted Answer

A)    H2(g)+   I2(g)   HI(g) 
B)  HI(g)     H2(g)+   I2(g) 
C)    H2(aq)+   I2(aq)   HI(aq) 
D)  HI(aq)     H2(aq)+   I2(aq) 
E)  2 HI(g)   H2(g)+ I2(g) 
A)    H2(g)+   I2(g)   HI(g) 
B)  HI(g)     H2(g)+   I2(g) 
C)    H2(aq)+   I2(aq)   HI(aq) 
D)  HI(aq)     H2(aq)+   I2(aq) 
E)  2 HI(g)   H2(g)+ I2(g)

Question 14

A 3.00-liter flask initially contains 3.00 mol of gas A and 1.50 mol of gas B.Gas A decomposes according to the following reaction: 3A   2B + C
The equilibrium concentration of gas C is 0.134 mol/L.Determine the value of the equilibrium constant,Kc.

Accepted Answer

A)  0.172 
B)  0.132 
C)  3.19 × 10-3 
D)  0.370 
E)  none of these 
A)  0.172 
B)  0.132 
C)  3.19 × 10-3 
D)  0.370 
E)  none of these

Question 15

At a high temperature,equal concentrations of 0.160 mol/L of H2(g)and I2(g)are initially present in a flask.The H2 and I2 react according to the balanced equation below. H2(g)+ I2(g)   2 HI(g)
When equilibrium is reached,the concentration of H2(g)has decreased to 0.036 mol/L.What is the equilibrium constant,Kc,for the reaction?

Accepted Answer

A)  3.4 
B)  4.0 
C)  12 
D)  22 
E)  48 
A)  3.4 
B)  4.0 
C)  12 
D)  22 
E)  48

Question 16

For which of the following reactions is Kp = Kc?

Accepted Answer

A)  2 CO2(g)   2 CO(g)+ O2(g) 
B)  CH4(g)+ 2 O2(g)   CO2(g)+ 2 H2O(g) 
C)  C(s)+ H2O(g)   H2(g)+ CO(g) 
D)  NH3(g)   3/2 H2(g)+ 1/2 N2(g) 
E)  2 O3(g)   3 O2(g) 
A)  2 CO2(g)   2 CO(g)+ O2(g) 
B)  CH4(g)+ 2 O2(g)   CO2(g)+ 2 H2O(g) 
C)  C(s)+ H2O(g)   H2(g)+ CO(g) 
D)  NH3(g)   3/2 H2(g)+ 1/2 N2(g) 
E)  2 O3(g)   3 O2(g)

Question 17

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

Accepted Answer

A)  3.08 × 104 
B)  3.25 × 10-5 
C)  9.96 × 10-15 
D)  1.00 × 1014 
E)  1.75 × 10-5 
A)  3.08 × 104 
B)  3.25 × 10-5 
C)  9.96 × 10-15 
D)  1.00 × 1014 
E)  1.75 × 10-5

Question 18

Nitrogen and oxygen gases may react to form nitrogen monoxide.At 1500 °C,Kc equals 1.0 × 10−5. N2(g)+ O2(g)   2 NO(g)
If 0.030 mol N2 and 0.030 mol O2 are sealed in a 1.0 L flask at 1500 °C,what is the concentration of NO(g)when equilibrium is established?

Accepted Answer

A)  3.0 × 10−7 M 
B)  4.7 × 10−5 M 
C)  9.5 × 10−5 M 
D)  3.0 × 10−2 M 
E)  9.1 × 101 M 
A)  3.0 × 10−7 M 
B)  4.7 × 10−5 M 
C)  9.5 × 10−5 M 
D)  3.0 × 10−2 M 
E)  9.1 × 101 M

Question 19

Given the following equilibria, Ni2+(aq)+ 2 OH-(aq)   Ni(OH)2(s)
K1 = 1.8 × 1015
Ni2+(aq)+ 4 CN-(aq)   Ni(CN)42-(aq)
K2 = 2.0 × 1031
Determine the equilibrium constant,Kc,for the following reaction.
Ni(OH)2(s)+ 4 CN-(aq)   Ni(CN)42-(aq)+ 2 OH-(aq)

Accepted Answer

A)  2.8 × 10-47 
B)  9.0 × 10-17 
C)  1.8 × 1015 
D)  1.1 × 1016 
E)  3.6 × 1046 
A)  2.8 × 10-47 
B)  9.0 × 10-17 
C)  1.8 × 1015 
D)  1.1 × 1016 
E)  3.6 × 1046

Question 20

Consider the following equilibria. PbBr2(s)   Pb2+(aq)+ 2 Br-(aq)
K1 = 6.6 × 10-6
Pb(OH)2(s)   Pb2+(aq)+ 2 OH-(aq)
K2 = 1.4 × 10-15
Determine the equilibrium constant,Kc,for the reaction below.
PbBr2(s)+ 2 OH-(aq)   Pb(OH)2(s)+ 2 Br-(aq)

Accepted Answer

A)  9.2 × 10-21 
B)  2.1 × 10-10 
C)  6.6 × 10-6 
D)  4.7 × 109 
E)  1.1 × 1020 
A)  9.2 × 10-21 
B)  2.1 × 10-10 
C)  6.6 × 10-6 
D)  4.7 × 109 
E)  1.1 × 1020

Exam 16: Principles of Chemical Reactivity: Equilibria

Which of the following expressions for K is correct for the reaction given below? HF(aq)+ H2O( ) F-(aq)+ H3O+(aq)

The symbol Q is called the ________.

When 0.20 mole HF is dissolved in water to a volume of 1.00 L,5.8% of the HF dissociates to form F-(aq).What is the equilibrium constant for the reaction? HF(aq)+ H2O( ) F-(aq)+ H3O+(aq)

The equilibrium constant,K,is always the same within experimental error for all experiments done at a given temperature.

A 10.0 g sample of solid NH4Cl is heated in a 5.00 L container to 900 °C.At equilibrium,the pressure of NH3(g)is 1.17 atm.Calculate the equilibrium constant,Kp,for the reaction below. NH4Cl(s) NH3(g)+ HCl(g)

The thermochemical equation for the formation of ammonia from elemental nitrogen and hydrogen is as follows. N2(g)+ 3 H2(g) 2 NH3(g) ΔH = -92.2 kJ Given a system that is initially at equilibrium,which of the following actions cause the reaction to proceed to the left?

Consider the following equilibrium: C2H6(g)+ C5H12(g) CH4(g)+ C6H14(g); Kp = 9.57 at 500 K Suppose 22.7 g each of CH4,C2H6,C5H12,and C6H14 are placed in a 35.0-L reaction vessel at 500 K.Which of the following statements is correct?

A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature. 3H2 + N2 2NH3 An analysis of the mixture at equilibrium revealed 2.1 mol N2,2.8 mol H2,and 1.8 mol NH3.How many moles of H2 were present at the beginning of the reaction?

When the pressure of an equilibrium mixture of SO2,O2,and SO3 is doubled at constant temperature,what the effect on Kp? 2SO2(g)+ O2(g) 2SO3(g)

If Kc = 0.124 for A2 + 2B 2AB,what is the value of Kc for the reaction 4AB 2A2 + 4B?

Which of the following is the correct balanced equation for the equilibrium constant expression given below?

A 3.00-liter flask initially contains 3.00 mol of gas A and 1.50 mol of gas B.Gas A decomposes according to the following reaction: 3A 2B + C The equilibrium concentration of gas C is 0.134 mol/L.Determine the value of the equilibrium constant,Kc.

For which of the following reactions is Kp = Kc?

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

Nitrogen and oxygen gases may react to form nitrogen monoxide.At 1500 °C,Kc equals 1.0 × 10−5. N2(g)+ O2(g) 2 NO(g) If 0.030 mol N2 and 0.030 mol O2 are sealed in a 1.0 L flask at 1500 °C,what is the concentration of NO(g)when equilibrium is established?

Given the following equilibria, Ni2+(aq)+ 2 OH-(aq) Ni(OH)2(s) K1 = 1.8 × 1015 Ni2+(aq)+ 4 CN-(aq) Ni(CN)42-(aq) K2 = 2.0 × 1031 Determine the equilibrium constant,Kc,for the following reaction. Ni(OH)2(s)+ 4 CN-(aq) Ni(CN)42-(aq)+ 2 OH-(aq)

Consider the following equilibria. PbBr2(s) Pb2+(aq)+ 2 Br-(aq) K1 = 6.6 × 10-6 Pb(OH)2(s) Pb2+(aq)+ 2 OH-(aq) K2 = 1.4 × 10-15 Determine the equilibrium constant,Kc,for the reaction below. PbBr2(s)+ 2 OH-(aq) Pb(OH)2(s)+ 2 Br-(aq)

Basic Concepts of Chemistry

Lets Review: The Tools of Quantitative Chemistry

Atoms, molecules, and Ions

Chemical Reactions

Stoichiometry: Quantitative Information About Chemical Reactions

Principles of Chemical Reactivity: Energy and Chemical Reactions

The Structure of Atoms

The Structure of Atoms and Periodic Trends

Bonding and Molecular Structure

Bonding and Molecular Structure Orbital Hybridization and Molecular Orbitals

Gases and Their Properties

Intermolecular Forces and Liquids

The Solid State

Solutions and Their Behavior

Chemical Kinetics: the Rates of Chemical Reactions

Principles of Chemical Reactivity: the Chemistry of Acids and Bases

Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

Principles of Chemical Reactivity: Entropy and Free Energy

Principles of Chemical Reactivity: Electron Transfer Reactions

Environmental Chemistry: Earths Environment, energy, and Sustainability

The Chemistry of the Main Group Elements

The Chemistry of the Transition Elements

Carbon: Not Just Another Element

Biochemistry

Nuclear Chemistry

Filters

Which of the following expressions for K is correct for the reaction given below? HF(aq)+ H₂O( ) F^-(aq)+ H₃O⁺(aq)

When 0.20 mole HF is dissolved in water to a volume of 1.00 L,5.8% of the HF dissociates to form F^-(aq).What is the equilibrium constant for the reaction? HF(aq)+ H₂O( ) F^-(aq)+ H₃O⁺(aq)

A 10.0 g sample of solid NH₄Cl is heated in a 5.00 L container to 900 °C.At equilibrium,the pressure of NH₃(g)is 1.17 atm.Calculate the equilibrium constant,Kp,for the reaction below. NH₄Cl(s) NH₃(g)+ HCl(g)

The thermochemical equation for the formation of ammonia from elemental nitrogen and hydrogen is as follows. N₂(g)+ 3 H₂(g) 2 NH₃(g) ΔH = -92.2 kJ Given a system that is initially at equilibrium,which of the following actions cause the reaction to proceed to the left?

Consider the following equilibrium: C₂H₆(g)+ C₅H₁₂(g) CH₄(g)+ C₆H₁₄(g); K_p = 9.57 at 500 K Suppose 22.7 g each of CH₄,C₂H₆,C₅H₁₂,and C₆H₁₄ are placed in a 35.0-L reaction vessel at 500 K.Which of the following statements is correct?

A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature. 3H₂ + N₂ 2NH₃ An analysis of the mixture at equilibrium revealed 2.1 mol N₂,2.8 mol H₂,and 1.8 mol NH₃.How many moles of H₂ were present at the beginning of the reaction?

When the pressure of an equilibrium mixture of SO₂,O₂,and SO₃ is doubled at constant temperature,what the effect on K_p? 2SO₂(g)+ O₂(g) 2SO₃(g)

If K_c = 0.124 for A₂ + 2B 2AB,what is the value of K_c for the reaction 4AB 2A₂ + 4B?

A 3.00-liter flask initially contains 3.00 mol of gas A and 1.50 mol of gas B.Gas A decomposes according to the following reaction: 3A 2B + C The equilibrium concentration of gas C is 0.134 mol/L.Determine the value of the equilibrium constant,K_c.

For which of the following reactions is K_p = K_c?

Given the equilibrium constants for the equilibria, NH₄⁺(aq)+ H₂O(l) NH₃(aq)+ H₃O⁺(aq); K_c = 2H₂O(l) 2H₃O⁺(aq); K_c = determine K_c for the following equilibrium. CH₃COOH(aq)+ NH₃(aq) CH₃COO−(aq)+ NH₄⁺(aq)

Nitrogen and oxygen gases may react to form nitrogen monoxide.At 1500 °C,K_c equals 1.0 × 10−⁵. N₂(g)+ O₂(g) 2 NO(g) If 0.030 mol N₂ and 0.030 mol O₂ are sealed in a 1.0 L flask at 1500 °C,what is the concentration of NO(g)when equilibrium is established?

Given the following equilibria, Ni²⁺(aq)+ 2 OH^-(aq) Ni(OH)₂(s) K₁ = 1.8 × 10¹⁵ Ni²⁺(aq)+ 4 CN^-(aq) Ni(CN)₄^2-(aq) K₂ = 2.0 × 10³¹ Determine the equilibrium constant,K_c,for the following reaction. Ni(OH)₂(s)+ 4 CN^-(aq) Ni(CN)₄^2-(aq)+ 2 OH^-(aq)

Consider the following equilibria. PbBr₂(s) Pb²⁺(aq)+ 2 Br^-(aq) K₁ = 6.6 × 10^-6 Pb(OH)₂(s) Pb²⁺(aq)+ 2 OH^-(aq) K₂ = 1.4 × 10^-15 Determine the equilibrium constant,K_c,for the reaction below. PbBr₂(s)+ 2 OH^-(aq) Pb(OH)₂(s)+ 2 Br^-(aq)