kinetics how do so stuff Flashcards
how can you tell if a reaction is zero order
graph time x axis and concentration of the right axis, if this is a straight line then the reaction is 0 order
how can you tell if a reaction is first order
graph time x axis and ln[conc] y axis - straight line is therefore 1st order
how can you tell if a reaction is second order
graph time x axis and 1/c y axis and a straight line means second order
how to tell the overall order of a reaction
prepare all 3 graph plots and see which one gives the most linear plot
what is the rate law equation for 0 order
rate = k[A]0
what is the rate law equation for 1 order
rate = k[A]1
what is the rate law equation for 2 order
rate = k[A]2
what is the integrated rate laws for a zero order reaction
[A] = [A]0-kt
what is the integrated rate law for a first order reaction
[A] = [A]0 e^-kt
what is the integrated rate law for a second order reaction
[A] = [A]0/(1+Kt[A]0)
how do we calculate the rate constant k
to calculate the rate constant K, calculate the gradient of the graph using the 1st and last point and use the equation = y2-y1/x2-x1
what are the units of K for a zero order reaction
Ms-1
what are the units of K for a first order reaction
s-1
what are the units of K for a second order reaction
M-1s-1
how do we calculate half life for a 0 order reaction
t1/2 = [A]0/2k
how do we calculate half life for a 1 order reaction
t1/2 = 0.693/k
how do we calculate half life for a second order reaction
t1/2 = 1/K[A]0
how do we calculate the reaction lifetime
for 1st order reactions only
= 1/K
how do we calculate concentration after a given time
use integrated rate law and extrapolate the value of the [A]0 from the intercept on the y axis
how do we calculate the activation energy for two points
ln(k1/k2) = EA/R(1/t2-1/t1)
use T in kelvin
how do we calculate the pre exponential factor for two points
rearrange the arrhenius equation to give
ln(A) = lnK2 +EA/RT2
solve this for Ln(A) and then e ans for A
what are the units of A
1st order = s-1
2nd order = M-1S-1
how do you find the activation energy for more than 2 points
plot the graph of lnK vs 1/T
calculate the gradient which will be -EA/R and then times by R to get EA
how do we calculate the A for more than 2 point
LnA will be the y intercept of the graph therefore A will be eans
