16.1/R2.2.6 Reaction mechanism, order of reaction and rate-determining step [HL IB Chemistry]

Rate = k [product of the reactants in the rate determining step] but it could be more complex - see the vid.

Make sure that when you "add up" the mechanism it equals your initial given equation.

Was the stair that Dr Atkinson demised on his personal "rate determining step"?

[Kublai_jesus]

Thanks for saving my grades good sir. I swear Khan academy and other "famous channels" are so overrated. Best online tutoring video, with the zombies and all. Amazing.

[JCheng]

i have to say that this video was tremendously helpful. i agree, rate equations are just one of those things you have to just know. anyways i have my paper 1 and 2 tomorrow and this video really helped. perhaps ill see one of those equations tomorrow. thank you for all your hard work, you're a great teacher, please continue to make these for the benefit of kids around the world

[sabrinawang]

can i hire u on behalf of my school lol

[amandagunasinghe]

LOL ''IDK HOW TO TEACH THIS'' but u did teach me!! my teacher knows or at least he think he knows and I never understood! So thank you :) 5 days away from exams ugh! Thanks again I wouldn't be able to find a better way to revise. I love you Mr.Thornley!

[jenachainika]

Your videos are the best I've seen so far. Thanks a lot!!! Hope you'll complete all of the sections. Cheers!

[sufiyashah]

Hello! Thank you so much for all the videos. You are the best youtube teacher for ib chemistry! I also suggested you to my friends :)))

[Leszek]

at 4:20, couldn't the second example work? What if we found experimentally that the coefficient for [B] is 0 and 2 for [A]?

[IanSamirYepManzano]

For the final problem, couldn't the second step also be the RDS???
Kind Regards

[ibchemvids]

You can never assume that the coefficients are the exponents - but they may end up as them.
eg If the reaction mechanism is only one step

[nima]

@Richard Thornley

Is this correct:

A + B -> AB
AB + C -> ABC
A + B + C -> ABC

[JulesNE]

Love your videos!Just wondering, the part with the zombies and the station... is that a video game? Where is that from?

[georginasmethurst]

For the medium example, rate=k[A][A] was simplified to rate=k[A]^2. Does that then make A second order?

[deanbitton]

Will the following mechanism also work?
2N2O -> 2NO + N2
2NO + N2 -> 2N2 + O2
Where the first step is the rate determining step?

[hagalive]

But the syllabus says "Only examples with one- or two-step reactions
where the mechanism is GIVEN will be assessed."

So we don't need to come up with the mechanisms?

[macjimenez]

Are all the orders you are putting assumptions? Because if we experimentally determined the order and came out different. I'll just tell my students to assume the order since the objective here is different.

[ibchemvids]

They have asked in the recent past for mechanisms.

[joshhayden]

Hello Mr. Thornley. I just have a quick question (video was very helpful by the way). I understand that when writing the rate expression, you have to make sure the concentrations used in the expression have to be of reactants in the overall equation, but what if the first step is the rds with a two reactants, one as a catalyst and the other as a reactant in the final equation? Do you write the expression using the concentration of the catalyst even though it isn't in the overall equation? Hope this question makes sense haha thanks either way!

[ibchemvids]

The o2 has to break at some stage to make a new molecule. Monatomic oxygen is very unstable and reactive - so this is a very short lived specie.

[aurielle]

for the 2-step mechanisms you wrote (with N2O -> N2 + O / N2O + O -> N2 + O2), I thought oxygen is diatomic so it should always come in pairs?

[echelontimepieces]

so if its the rate determining step, the coefficients become the exponents?