[petstar21]

1. SO I wasn;t sure which was correct:
X, Y, and Z are the reactants. [X] and [y] are DIRECTLY PROPORTIONAL to the rate. [Z] squared is proportional to the rate. whats the rate law?
i thought it was R= k[X][Y][Z}^2

but could i have been wrong and the answer be- R= k [X][Y]/[Z]^2??

2. here was the diagram..http://i241.photobucket.com/albums/ff145/petstar21/pediagram.jpg
excuse my art skills!
so my question is how many steps are there is the reaction... my assumtion was 3.
and how many intermediate products are there and why? i was guessing 3 bc the activated comples is formed and then used up thereby making it an intermediate product as well, no?

thanks

[cliverlong]

1. SO I wasn;t sure which was correct:
X, Y, and Z are the reactants. [X] and [y] are DIRECTLY PROPORTIONAL to the rate. [Z] squared is proportional to the rate. whats the rate law?
i thought it was R= k[X][Y][Z}^2

but could i have been wrong and the answer be- R= k [X][Y]/[Z]^2??

Have a look at my posting here
http://www.chemicalforums.com/index.php?topic=26499.msg99745#msg99745

and then check the form of the rate equation. Without giving too much away, is a quotient involved in any form of the rate equation?
Ensure you are not confusing the form of the rate equation with the equlibrium constant.

What do you think now is the correct form of your rate equation?

2. here was the diagram..http://i241.photobucket.com/albums/ff145/petstar21/pediagram.jpg
excuse my art skills!
so my question is how many steps are there is the reaction... my assumtion was 3.
and how many intermediate products are there and why? i was guessing 3 bc the activated comples is formed and then used up thereby making it an intermediate product as well, no?

thanks

Nice idea to scan the sketch

My first response is

What is being measured on the horizontal axis?
What is being measured on the vertical axis?

Then I guess your question is about reaction mechanisms. This is a topic I find explained woolyly (new word) at best

All the explanations and proposals I have read on this topic makes sense to me if only ONE concentration term is non-zero-order in the rate equation - e.g rate = k[NO] - then that is the ONLY chemical that supplies the participating or active species in the rate determining step. More than one concentration term and it all seems too complex to me.

The explanations  I have read that relate rate to mechanism seem smoke and mirrors to me.

Jim Clarke is probably the best on this topic

http://www.chemguide.co.uk/physical/basicrates/ordermech.html

What do you think?


Clive

[Rabn]

In response to #2)  There are 3 steps, each step has its own activation energy. The # of intermediates.....consider the deifintion of what a reaction intermediate is.  During the course of a reaction you have intermediates which are fairly stable and transition states which are highly unstable and only exist for an extremely short period of time. Armed with that info, what do you think?