Unit 5

unimolecular/bimolecular/termolecular reaction

one/two/three reactant molecules involved

intermediate

produced in an earlier step and used as a reactant in a later step

how to find rate law of an elementary step

coefficients for stoichiometry are order for each reactant

reaction rate maxwell-boltzman graph

higher temp/wider distribution = more molecules moving at faster speeds = more have sufficient energy for reaction

activation energy

Ea, the minimum amount of energy required to activate atoms or molecules to where they can do the reaction, between starting energy and peak of graph

enthalpy change

ΔH, amount of energy given off/absorbed by a reaction, positive = endothermic, negative = exothermic

arrhenius equation main point

as temp goes up, reaction rate goes up

catalyst

lower Ea to make reaction faster, used up in an early step but formed in a later step, starting reactant and at the end

what the rate law/reaction order is set by

slowest elementary step

activation energy when reversing reaction

ΔH + original Ea

things that affect reaction rate

concentration, temp, surface area (higher = faster), catalysts

reaction order

how important the concentration of a given reactant is for how quickly the reaction progresses

zero order y axis

[A]

first order y axis

ln [A]

second order y axis

1/[A]

how to tell slow/fast steps from graph of reaction

peak with higher energy is slower step

how catalysts increase reaction rate

introducing more collisions or improving collision orientation

homogenous catalyst

same phase as reactants

heterogeneous catalyst

in different phase than reactants

0 order k units

M s^-1

1st order k units

s^-1

2nd order k units

M^-1 s^-1

3rd order k units

M^-2 s^-1