Rates Flashcards
(20 cards)
Rate equation
R = K[ A] ^n [B] ^n
What 3 orders are there
0,1,2
Define rate of reaction
Change in concentration or amount of reactant or product over time
Units for rate
Moldm3-1
Zero order
Change in concentration has no effect on rate
1st order
Change is concentration has a proportional effect on rate
2nd order
Change in concentration has a squared proportional change on rate
Zero order in rate equation
Don’t include
Iodine clock experiment
Measure hoe long it takes fir Colin chase to occur
Add sodium thiosulphate and starch which acts as an indicator
Sodium thiosulphate reacts with the I2 produced. When no more sodium thiosulphate then I2 rafts with starch and you time this and watch with ur eye
Changing the concentration of I2 and H2O2 will result in the time taken changing
Reaction equation for iodine clock experiment
Half equation for H2O2 to H2O
And I- to I2
How can rates be measured in experiments?
- Change on PH over time as H+ ions produced or lost
- Amount of mass lost
- Amount of gas produce in a syringe
Why can you used to measure rate of a Colour change
Colorimeter
Graph for concentration v time for zero order
Graph for concentration v time for 1st order
Graph for concentration v time for 2nd order
Graph for rate v time for zero order
Graph for rate v time for 1st order
Graph for rate v time for 2nd order
Rate determining step
Slowest step
Must be in rate equation
Look at ratio of moles
Arrhenius equation
K = Ae^ -Ea/RT
A = Arrhenius constant
e=2.718
-Ea= activation energy in joules
R=8.31
T = temperature in kelvin
