Chemical industry Flashcards
gradient=?
change in y / change in x
inital rate=?
amount reactant used/ time
how do you do a clock reaction?
- iodine clock
- sodium thiosulphate and starch to excess hydrogen peroxide and iodide ions in acid solution
- sodium thiosulphate reacts immediatley with iodine formed
- goes black at the end point as no more thiosulphate left to react with iodine
rate=?
k[A]^m[B]^n
what is zero order?
[a] changes but rate stays the same 0 order. rate completely independent to [a]
what is 1st order?
rate proportional to [A]
what is 2nd order?
rate is proportional to [A]^2
what is the half life?
time taken for half the reactant to be sued up.
if half life constant then 1st order
how do you find the rate constant from the half-life?
k= ln2/ half-iife
does temperature affect the rate reaction?
only effects the rate constant because it doesn’t change the concentrations of reactants.
in the AE, what happens when activation enthalpy gets bigger?
- k gets smaller
- slow rate too as fewer molecules can get the energy to begin a reaction
what is Arrhenius as a logarithmic scale? how do you plot on a graph?
lnk = - (Ea/RT) + lnA
- plot lnk against 1/T
- this makes a gradient of -Ea/ R and a y intercept of lnA
how can you predict the rate equation from the rate determining step?
the order shows the number of molecules in the rate-determining step.
what effects Kc?
temperature does
pressure doesnt
catalysts dont
why is nitrogen so unreactive?
has a triple bond
