Kinetics and Equilibrium Flashcards
Kinetics
Movement of particles
Collision theory
Increasing the number of collisions will increase the number of effective collisions
6 ways to increase the rate of a reaction
1) Add a catalyst
2) Increase pressure of gases
3) Increase temperature
4) Increase surface area
5) Increase concentration of reactant particles
6) Nature of reactants (Group 1 and 2, F)
Effective collisions produce
The desired products
2 requirements for an effective collision
1) Proper orientation
2) Sufficient energy
When heat is on the product or right side of an equation, the forward reaction is
Exothermic
When heat is on the reactant or left side of an equation, the forward reaction is
Endothermic
A product produced from which reaction, endothermic or exothermic, is more stable?
Exothermic products because low energy is associated with stability
53 kJ + H2 + I2 -> 2HI, how much heat is absorbed in the production of 4 moles of HI?
Double it, so 106 kJ
For solution equilibrium, you must have a
Saturated solution
LeChatelier’s Principle
If a chemical system at equilibrium is stressed in some way, it undergoes a change that tends to reduce the effects of stress
3 types of stresses
a) Change in concentration
b) Change in temperature
c) Change in pressure
Increasing the concentration of the reactants increases the rate of the
Forward reaction
Increasing the concentration of the products increases the rate of the
Reverse reaction
What concentration is increased, there is a
Shift away from that substance
Decreasing the concentration of the reactants increase the rate of the
Reverse reaction
Decreasing the concentration of products increases the rate of the
Forward reaction
Whatever concentration is removed,
The reaction produces more of it is favored
Pressure changes applies only to
Gases
Increase in pressure
Shift to the side with less moles of gas
Decrease in pressure
Shift to side with more moles of gas
Decrease in temperature
Exothermic reaction is favored
Increase in temperature
Endothermic reaction is favored
What happens when you add a catalyst?
No change in equilibrium, but increased the rate of the forward and reverse reactions equally
Entropy
Measure of a system’s randomness or disorder
What happens to entropy as you move from water in the solid phase to water in the gas phase?
Entropy increases, more disorder and less order
True or false: Pieces and parts have greater entropies than compounds
True!
Spontaneous reaction
One that will take place under given conditions
What promotes a spontaneous reaction?
An exothermic reaction or one that goes to lower energy with an increase in entropy
