Advanced Chemistry Name __________________________

Hour _______

Advanced Chemistry

Approximate Timeline

Students are expected to keep up with class work when absent.

CHAPTER 13 – CHEMICAL EQUILIBRIUM Day Plans for the day Assignment(s) for the day

1

13.1 – The Equilibrium Condition

o Reaching Equilibrium

o The Equilibrium Condition

Assignment 13.0

Read section(s) 13.2

2

13.2 – The Equilibrium Constant

o Kc

o Kp

o Heterogeneous Equilibria

Assignment 13.1

Read section(s) 13.5 – 13.6

3

13.5 – Applications of the Equilibrium

Constant

13.6 – Solving Equilibrium Problems

4

13.5 – Applications of the Equilibrium

Constant

13.6 – Solving Equilibrium Problems

Assignment 13.2

Read section(s) 13.7

5

13.7 – Le Chatelier’s Principle

o The Effect of a Change in

Concentration

o The Effect of a Change in Pressure /

Volume

o The Effect of a Change in Temperature

Assignment 13.3

6 Grade & discuss assignment

Review for Chapter 13 Test

7 Chapter 13 Test Read section(s) 14.1 – 14.2

Advanced Chemistry Name __________________________

Hour _______

Study Guides

Chapter 13 Quizzes

Quiz 13.1 – The Equilibrium Condition

1. Define chemical equilibrium.

2. What does the author mean when he says that equilibrium is a “dynamic situation”?

3. Write equilibrium constant expressions for homogeneous systems and heterogeneous

systems.

Quiz 13.2 – 13.4

13.2 – The Equilibrium Constant

(i) j A + k B l C + m D

(ii)

4. Look at equation (i). What does the "double arrow" () indicate?

5. Look at equation (ii). What name is given to the "K"?

13.4 – Heterogeneous Equilibria

6. What is the primary difference between homogeneous equilibrium and heterogeneous

equilibrium?

7. Consider a heterogeneous system at equilibrium. When writing the equilibrium constant

expression,

a. which physical states are included?

b. which physical states are NOT included?

8. Use the equilibrium constant to determine:

a. whether or not a system is at equilibrium

b. the pressure/concentration of a particular chemical

Quiz 13.5 – Applications of the Equilibrium Constant

9. Quoting the first sentence of section 13.5, "Knowing the equilibrium constant for a

reaction allows us to predict several important features of the reaction:" What are the

three important factors mentioned?

Quiz 13.7 – Le Châtelier’s Principle

10. State Le Chatelier's Principle.

11. An important reaction is the commercial production of hydrogen is:

12. 2 H2O (g) 2 H2 (g) + O2 (g); H = endothermic

a. In which direction will the equilibrium shift in each of the following cases?

b. Gaseous hydrogen is removed.

c. Water vapor is added.

d. The pressure is increased.

e. The temperature is increased.

f. The volume is decreased.

Advanced Chemistry Name __________________________

Hour _______

Study Guide

Chapter 13 Test

Advanced Chemistry

At the completion of chapter 13 you should…

1. Know the definitions of the following terms.

a. Chemical Equilibrium

b. Equilibrium Expression

c. Equilibrium Constant

d. Homogeneous Equilibrium

e. Heterogeneous Equilibrium

f. Le Châtelier’s Principle

2. Be able to write equilibrium constant expressions.

a. homogeneous equilibrium

b. heterogeneous equilibrium

c. changes to the system

i. changing the coefficients

ii. writing the chemical equation backwards

iii. combining i and ii

3. Be able to solve all types of equilibrium problems.

a. The direction the system will shift to reach equilibrium.

b. Pressures or concentrations of equilibrium species.

4. Use Le Chatelier’s Principle to predict the effect of ___ on equilibrium systems.

a. Concentration changes

b. Pressure changes

c. Temperature changes

Assignment 13.0 – Vocabulary

Define each of the following terms.

1. Chemical Equilibrium

2. Equilibrium Expression

3. Equilibrium Constant

4. Homogeneous Equilibrium

5. Heterogeneous Equilibrium

6. Le Châltelier’s Principle

Advanced Chemistry Name __________________________

Hour _______

Assignment 13.1 – The Equilibrium Constant

1) Write the equilibrium expression (Kc) for each of the following gas-phase reactions.

A) N2 (g) + O2 (g) 2 NO (g)

B) N2O4 (g) 2 NO2 (g)

C) SiH4 (g) + 2 Cl2 (g) SiCl4 (g) + 2 H2 (g)

D) 2 PBr3 (g) + 3 Cl2 (g) 2 PCl3 (g) + 3 Br2 (g)

2) Write the equilibrium expression (Kp) for each reaction in #1.

A)

B)

C)

D)

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Hour _______

3) For the reaction: H2 (g) + Br2 (g) 2 HBr (g), Kp = 3.5 x 104 at 1495 Kelvin. What

is the value of Kp for the following reactions at 1495 Kelvin?

A) HBr (g) ½ H2 (g) + ½ Br2 (g)

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

C) ½ H2 (g) + ½ Br2 (g) HBr (g)

4) For the reaction: N2 (g) + 3 Cl2 (g) 2 NCl3 (g) an analysis of an equilibrium

mixture is performed at a certain temperature. It is found that [NCl3] = 0.19 M, [N2] =

0.0014 M, and [Cl2] = 0.00043 M. Calculate the value of the equilibrium constant, K, for

this reaction at this temperature.

5) The following equilibrium pressures were observed at a certain temperature for the

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

= 0.55 atm

= 0.85 atm

= 0.0031 atm

A) Calculate the value for the equilibrium constant, Kp, at this temperature.

B) If = 0.525 atm,

= 0.0167 atm, and = 0.00761 atm, does this

represent a system at equilibrium?

Advanced Chemistry Name __________________________

Hour _______

Assignment 13.2 – Equilibrium Calculations

1) The equilibrium constant, Kp, is 2.4 x 10

3 at a certain temperature for the reaction:

2 NO (g) N2 (g) + O2 (g)

For which of the following sets of conditions is the system at equilibrium?

A) = 0.010 atm, = 0.11 atm,

= 2.0 atm

B) = 0.0078 atm, = 0.36 atm,

= 0.67 atm

C) = 0.0062 atm, = 0.51 atm,

= 0.18 atm

2) For the reaction below K = 2.4 x 10-3

at a given temperature. At equilibrium it is found

that [H2O] = 1.1 x 10-1

M and [H2] = 1.9 x 10-2

M. What is the concentration of O2 under

these conditions? 2 H2O (g) 2 H2 (g) + O2 (g)

Advanced Chemistry Name __________________________

Hour _______

3) For the reaction below Kp = 109 at 25°C. If the equilibrium partial pressure of Br2 is

0.0159 atm and the equilibrium partial pressure NOBr is 0.0768 atm, calculate the partial

pressure of NO at equilibrium. 2 NO (g) + Br2 (g) 2 NOBr (g)

4) At a particular temperature, 12.0 mol of SO3 is placed into a 3.0 L rigid container, and the

SO3 dissociates by the reaction below. At equilibrium, 3.0 mol of SO2 is present.

Calculate K for this reaction. 2 SO3 (g) 2 SO2 (g) + O2 (g)

5) At a certain temperature, 4.0 mol NH3 is introduced into a 2.0 L container, and the NH3

partially dissociates by the reaction below. At equilibrium 2.0 mol NH3 remains. What is

the value of K for this reaction? 2 NH3 (g) N2 (g) + 3 H2 (g)

6) At a particular temperature, Kp = 0.25 for the reaction:

N2O4 (g) 2 NO2 (g)

A) A flask containing only N2O4 at an initial pressure of 4.5 atm is allowed to reach

equilibrium. Calculate the equilibrium partial pressures of the gases.

B) A flask containing only NO2 at an initial pressure of 9.0 atm is allowed to reach

equilibrium. Calculate the equilibrium partial pressures of the gases.

C) From your answers to parts A and B, does it matter from which direction

equilibrium is established?

Advanced Chemistry Name __________________________

Hour _______

7) At 35°C, K = 1.6 x 10-5

for the reaction below. Calculate the concentration of all species

at equilibrium for each of the following original mixtures.

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

A) 2.0 mol pure NOCl in a 2.0 L flask.

B) 1.0 mol NOCl and 1.0 mol NO in a 1.0 L flask

C) 2.0 mol NOCl and 1.0 mol Cl2 in a 1.0 L flask

8) At a particular temperature, K = 4.0 x 10-7

for the reaction below. In an experiment, 1.0

mol N2O4 is placed in a 10.0 L vessel. Calculate the concentration of N2O4 and NO2 when

this reaction reaches equilibrium.

N2O4 (g) 2 NO2 (g)

Advanced Chemistry Name __________________________

Hour _______

Assignment 13.3 – Le Châtelier’s Principle

1) Predict the shift in the equilibrium position that will occur for each of the following

reactions when the volume of the reaction container is increased.

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

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

C) H2 (g) + F2 (g) 2 HF (g)

D) CoCl2 (g) CO (g) + Cl2 (g)

E) CaCO3 (s) CaO (s) + CO2 (g)

2) An important reaction in the commercial production of hydrogen is:

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

How will this system at equilibrium shift in each of the five following cases?

A) Gaseous carbon dioxide is removed.

B) Water vapor is added.

C) The pressure is increased by adding helium gas.

D) The temperature is increased (the reaction is exothermic).

E) The pressure is increased by decreasing the volume of the reaction container.

Advanced Chemistry Name __________________________

Hour _______

3) What will happen to the number of moles of SO3 in equilibrium with SO2 and O2 in the

reaction:

2 SO3 (g) 2 SO2 (g) + O2 (g) ΔH° = 197 kJ

in each of the following cases?

A) Oxygen is added.

B) The pressure in increased by decreasing the volume of the reaction container.

C) The pressure is increased by adding argon gas.

D) The temperature is decreased.

E) Gaseous sulfur dioxide is removed.