Chem Unit 4

Kinetics

Kinetics

factors that affect the speed of a reaction (how fast the reactant are converted into products)

Reaction Rate

amount of time it takes for reactants —> products

Factors that affect reaction rate

Temp

Concntration

Surface Area

Catalyst

Pressure

Nature of Reactants

Kinetics Temperature

increase temp causes molecule to move faster

Kinetics Concentration

if concentration is increased, more molecules are avalible to react

Kinetics Surface Area

increase surface area provides more molecules that are exposed

Kinetics Catalyst

speeds up a reaction, lowers the amount of energy needed for reaction to occur

Kinetics Pressure

Gas only

increase presure forces gas molecules closer together, increasing chance of reacting

Kinetics Nature of Reactants

State of Matter (solid, liquid, gas)

type of reactant (ionic vs covalent compound)

more bonds that need to be broken

Collision Theory

model that states that molecules (atoms, ions) must collide in order for a reaction to occur

• not all collisions result in a reaction

Ineffective Collision

does not result in a reaction

Effective Collision

leads to formation of products

• orientation of colliding molecules (lock and key)

• energy=colliding molecules must have sufficient energy when they collide in order to break old bonds and form new bonds

Synthesis

A+B →AB

Decomposition

AB →A+B

opposite of Synthesis

Combustion

C, H, O + O² → CO² + H²O

always involves molecule oxygen

Single Replacement

A+BC→AC+B

use Activity Series

one element replaces another in a compound

Double Replacement

AB+CD→AD+CB

use Solubility Rules

positive and negative ions of two reactants are interchanged