Unit 7 Kinetics And Equilibrium

Question 1

Define reaction rate

Answer 1

Two ways:

1) Decrease in concentration of reactants per unit of time
2) increase in concentration of products per unit of time

Question 2

What must happen for a reaction to occur?

Answer 2

1) Particles must collide
2) Particles must be properly aligned
3) Particles must have enough energy

Question 3

How do you increase reaction rate?

Answer 3

a) increase the frequency of collision

b) increase the energy with which they collide

Question 4

What are the factors that affect the number of effective collisions and reaction rate?

Answer 4

1) Concentration
2) Temperature
3) Surface Area
4) Catalyst

Question 5

Increasing temperature will increase the reaction rate in what way?

Answer 5

1) more collisions occur as average kinetic energy increases

2) more collisions have energy larger than activation energy

Question 6

How much of an increase in temperature can increase the reaction rate?

Answer 6

A 10 K increase will roughly double the reaction rate

Question 7

What does a catalyst do to increase reaction rate?

Answer 7

Catalysts reduce the activation energy of a substance for a given reaction

Question 8

What is a reversible reaction?

Answer 8

A reaction where products will collide and lead the the reforming of reactants

Question 9

What happens at equilibrium?

Answer 9

The forward reaction rate always equals the reverse reaction rate

Question 10

What is the equilibrium constant?

Answer 10

kc

Question 11

What is the equilibrium constant expression?

Answer 11

kc = products / reactants

Question 12

What is a homogeneous reaction?

Answer 12

A reaction where all reactants and products are in the same phase

Question 13

What does Le Chatelier’s Principle state?

Answer 13

When a stress is applied to a system, the system will readjust to reduce that stress.

Question 14

When is the forward reaction favored?

Answer 14

When forward is favored:

• reaction shifts towards the right side
• more products form
• amount of reactant decreases

Question 15

When is the reverse reaction favored?

Answer 15

When reverse favored:

• reaction shifts towards the left side
• more reactants form
• amount of products decreases

Question 16

What are the “main” stresses to apply on a system/reaction?

Answer 16

• Change in concentration
• Change in pressure
• Change in temperature

Question 17

Which side is the equilibrium shifted to in a pressure change?

Answer 17

The side with the least amount of moles of gas.

Question 18

Which side is the equilibrium shifted in a temperature change?

Answer 18

The side without the heat

Question 19

What is nitrogen fixation?

Answer 19

Changing N2 to a nitrogen compound

Question 20

What is the most common use of nitrogen compounds?

Answer 20

Compounds with nitrogen are often used to make explosives

Question 21

What is C3H5N3O9(l)

Answer 21

nitroglycerin

Question 22

What is the chemical equation when nitroglycerin is ignited?

Answer 22

4C3H5N3O9 -> 12CO2(g) + 10H2O(g) + O2(g) + 6N2(g) + energy

Question 23

What who made nitroglycerin safe to handle and when?

Answer 23

In 1867 Alfred Nobel added nitroglycerin to porous silica to make dynamite

Question 24

What did Fritz Haber do during his life?

Answer 24

Fritz Haber developed process to form ammonia from the nitrogen in the air and hydrogen from methane and steam

Question 25

What is the chemical reaction Fritz Haber developed?

Answer 25

N2(g) + 3H2(g) -> 2NM3(g) ΔH° = -92kJ/mol