rate laws

[recyrb]

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So I am now lost- great

when can we assume the rate law and the order of each from the given reaction?

can we only determine the order of each molecule from the Slow step, or if noted elementary reaction?

so-- slow step is

2HCl + NaOH <-->

if this is a real reaction--- does the rate law = rate law= K (HCl)2 (NaOH)

overall being 3rd order?

with the given reaction data its no problem, but without, when are the coeffecients not accounted for rate-- if its not elementary?

2HCl + NaOH <---> rate law=k (HCl) (NaOH)

If i see 2X of anything does that mean for the molecule it is 2nd order? FTW

 

[bharat008]

So I am now lost- great

when can we assume the rate law and the order of each from the given reaction?

can we only determine the order of each molecule from the Slow step, or if noted elementary reaction?

so-- slow step is

2HCl + NaOH <-->

if this is a real reaction--- does the rate law = rate law= K (HCl)2 (NaOH)

overall being 3rd order?

with the given reaction data its no problem, but without, when are the coeffecients not accounted for rate-- if its not elementary?

2HCl + NaOH <---> rate law=k (HCl) (NaOH)

If i see 2X of anything does that mean for the molecule it is 2nd order? FTW

There are only 2 ways to get a rate law. Firstly, if they gave you table with different trials then you can determine the rate law. Secondly, when they give you MECHANISM of the rxn that is when they tell you that out of these steps this is a slow step. Then you will use the slow step to write the RATE lAW (using the coeffecients of the reactants). The rate law of the slowest step is considered to be the rate law of the entire rxn b/c slow step takes the longest in the rxn while other steps go fast..

Therefore, the only way to get the rate law from mechanism is when they tell u that this specific elementary rxn is slowest step.. or give you the graph then the longest hill would be considered as the slowest step.
HOpe that would clear up your confusion abt rate laws..👍

 

[recyrb]

i think so~ so if its elementary or the slow step-- then the number of molecules/compounds is the order for that concentration?!

2HCl means that the concentration for HCl is second order???

thanks man!

this is what i originally thought, then i saw a problem that answered it differently, incorrectly, then of course, the whole world's entropy starts increasing!

 

[bharat008]

i think so~ so if its elementary or the slow step-- then the number of molecules/compounds is the order for that concentration?!

2HCl means that the concentration for HCl is second order???

thanks man!

this is what i originally thought, then i saw a problem that answered it differently, incorrectly, then of course, the whole world's entropy starts increasing!

For example::
the slow step is 4Pt + 4H2 = 4PtH2

Rate = k [Pt]^4 [H2]^4
Overall rate order is 8...