Unit 7 Kinetics And Equilibrium Flashcards
Define reaction rate
Two ways:
1) Decrease in concentration of reactants per unit of time
2) increase in concentration of products per unit of time
What must happen for a reaction to occur?
1) Particles must collide
2) Particles must be properly aligned
3) Particles must have enough energy
How do you increase reaction rate?
a) increase the frequency of collision
b) increase the energy with which they collide
What are the factors that affect the number of effective collisions and reaction rate?
1) Concentration
2) Temperature
3) Surface Area
4) Catalyst
Increasing temperature will increase the reaction rate in what way?
1) more collisions occur as average kinetic energy increases
2) more collisions have energy larger than activation energy
How much of an increase in temperature can increase the reaction rate?
A 10 K increase will roughly double the reaction rate
What does a catalyst do to increase reaction rate?
Catalysts reduce the activation energy of a substance for a given reaction
What is a reversible reaction?
A reaction where products will collide and lead the the reforming of reactants
What happens at equilibrium?
The forward reaction rate always equals the reverse reaction rate
What is the equilibrium constant?
kc
What is the equilibrium constant expression?
kc = products / reactants
What is a homogeneous reaction?
A reaction where all reactants and products are in the same phase
What does Le Chatelier’s Principle state?
When a stress is applied to a system, the system will readjust to reduce that stress.
When is the forward reaction favored?
When forward is favored:
- reaction shifts towards the right side
- more products form
- amount of reactant decreases
When is the reverse reaction favored?
When reverse favored:
- reaction shifts towards the left side
- more reactants form
- amount of products decreases
What are the “main” stresses to apply on a system/reaction?
- Change in concentration
- Change in pressure
- Change in temperature
Which side is the equilibrium shifted to in a pressure change?
The side with the least amount of moles of gas.
Which side is the equilibrium shifted in a temperature change?
The side without the heat
What is nitrogen fixation?
Changing N2 to a nitrogen compound
What is the most common use of nitrogen compounds?
Compounds with nitrogen are often used to make explosives
What is C3H5N3O9(l)
nitroglycerin
What is the chemical equation when nitroglycerin is ignited?
4C3H5N3O9 -> 12CO2(g) + 10H2O(g) + O2(g) + 6N2(g) + energy
What who made nitroglycerin safe to handle and when?
In 1867 Alfred Nobel added nitroglycerin to porous silica to make dynamite
What did Fritz Haber do during his life?
Fritz Haber developed process to form ammonia from the nitrogen in the air and hydrogen from methane and steam
What is the chemical reaction Fritz Haber developed?
N2(g) + 3H2(g) -> 2NM3(g) ΔH° = -92kJ/mol
