Reaction Kinetics

Reaction Kinetics

study of rate (factors that influence)

does rxn rate typically slow down, speed up or stay the same? Why?

slow down, reactants are consummed

rxn rate =

change in amount/change in time

what are the factors that influence rates (6)

temp, catalyst, surface area, pressure, concentration, nature of reactants

how does temp influence rate

an increase in temp increases rate, greater temp makes molecules move faster

how does a catalyst influence rate

increases rate (enzymes in bio) is not used up in the reaction. (may be used early in rxn but is later regenerated)

how does surface area influence rate

increase the surface area increases rates, only applies in HETEROGENOUS rxn, reduces kinetic energy required

which phase of chemical reacts fastest to which reacts slowest

Aq, gases, liquids, solid

what is a HETEROGENOUS rxn

more than one phase (aq, g, l, s)

Simular to a catalyst but slows down a rxn

inhibitor

how does pressure influence rate

increase pressure increases rate, only for gases

how does concentration influence rate

increase in concentration increases rate, only for aq and gases

how does nature of reactants influence rate

some chemicals react faster than others because of bonds. bonds in reactants need to break before new bonds in products can form

why would Na react faster than Li

because its lone electron is farther from the attractive nucleus

What is rate law

rxn rate = k[A]^x[B]^y looks at the impact a particular chemical has on a reaction rate

what are the exponents in the rate law equation

reactant orders

what does the k represent in rate law equation

rate constant

what is the overall order

The overall order of a chemical reaction is the sum of the individual reactant orders

what is intergrated rate law

looks at the chemicals concentration as a function of time

what does C_o represent

initial concentration of reactant

what does C represent

concentration of reactant at a specified time

1st order rxn integrated rate law

lnC = -kt + lnC_o

1st order reaction ½ life

t ½ = 0.693/k

2nd order reaction integrated rate law

1/C = kt + 1/C_o

0th order rxn integrated rate law

C = kt + C_o