Chemistry Regents Review: Kinetics/Equilibrium Notes & Unit 4.4/5.1 (week #6)

Collision Theory

reaction is most likely to occur if reactant particles collide with the proper energy and orientation

What does 1 represent?

activation energy for reactants

What does 2 represent?

activation energy for activated complex

What does 3 represent?

heat of the reaction

What does 4 represent?

activation energy for products

First 6 equations on Table I are all…

combustion

4 factors effecting reaction rates

• increasing temp

• increasing concentration

• increasing surface area

• catalyst

Increasing temperature…

faster moving particles →increased frequency of effective collisions

Increasing concentration…

more particles → closer tgth → more collisions

Increasing surface area….

breaking up bonds (powdered) → particle release & increased frequency of effective collisions

Catalyst

provides an alternative reaction pathway and lowers activation energy

Why doesn’t a catalyst shift the reaction?

it increases the rate of foward and reverse equally

Combustion

hydrocarbon + O2 → H2O + CO2 + energy (heat)

Heat of Reaction

PE products - PE reactants

Negative sign means exothermic so….

heat released from system to surroundings (air temp increases)

Exothermic Potential Energy Diagram

Endothermic Potential Energy Diagram

Equilibrium

rate of foward and reverse reactions is equal and concentrations of reactants and products is constant

Phase Equilibrium

occurs during phase changes

• melting

• freezing

• boiling

Le Chatelier’s Principle

if a stress is applied to a system at equilibrium, the equilbirium will shift to relieve that stress

3 ways to stress Equilibrium

• concentration

• pressure

• temperature

Concentration and Temperature Acronym

• Add Away

• Take Towards

Pressure Increases and Decreases shifts

• increases - less moles of gas

• decreases - more moles of gas

Synthesis Chemical Reaction

A + B → AB

Decomposition Chemical Reaction

AB → A +

Single Replacment

Dynamic Equilibrium

rate of dissolving = rate of recrystalization

Static Equilibrium

solution at rest and all external forces on it are balanced so there is no motion

Double Replacment

Vaporization

amount of energy it takes to vaporize a substance

• liquid to gas

Fusion

amount of energy required to melt

• solid to liquid

Low boiling points have a high vapor pressure because

its easier to overcome atmospheric pressure

A, C, and E

temperature increases while PE is constant

B and D

PE increases because changing phase while temperature is constant

In heat of fusion, the melting and refreezing energy amounts…

are the same

Specific Heat Capacity, delta T is

T final - T initial