orders, rate equations, rate constant

what effect does increasing the concentration of a zero order reactant have on rate

no effect

what effect does increasing the concentration of a first order reactant have on rate

increase is directly proportional

if concentration doubles, rate of reaction will double

what effect does increasing the concentration of a second order reactant have on rate

if concentration doubles, rate of reaction will increase 4x

the rate equation

rate = k[A]m[B]n

units for k in a zero order reaction

mol dm-3 s-1

units for k in a first order reaction

s-1

units for k in a second order reaction

dm3 mol-1 s-1

zero order reactant on a concentration time graph

straight line with negative gradient

gradient = k

first order reactant on a concentration time graph

downwards curve with decreasing gradient

half life of a first order reactant

constant half life

second order reactant on a concentration time graph

same as first order but starts steeper and trails off more quickly

calculating rate constant using half life

k = In2/half life

zero order reactant on a rate-concentration graph

horizontal straight line, with the y intercept being k

first order reactant on a rate-concentration graph

straight line through the origin

gradient = k

second order reactant on rate-concentration graph

curved line with increasing gradient

gradient of line on rate-concentration squared = k

what is the series of steps that make up a reaction called

reaction mechanism

which step is the rate-determining step

the slowest step

Arrhenius equation

rate = A e-Ea/RT

logarithmic form of Arrhenius equation

Ink = -Ea/R 1/T + Ina

y = m x + c