In one point the answer from ggdrasil is correct:
At the absolute final glance, the Reaction-Rate is ALL times THE complete
combination of ALL possible and impossible reaction-steps.
But his remaining picture is at least wrong coloured, and NEVER “crude” in any case, and sense, too!
Think about: You have to distinguish between two situations, a consecution of reaction-steps,
and one, or more, “sidecar”-reactions !!
But what’s the difference, and why is it important?:
A.) In a consecution “all” has to go through ONE and ONLY one AND the same Pipe,
what means that it has only as consequence: Even the faster as the fastest has
to wait for the slowest ever!
That’s why it is so extraordinary heavy to catch/detect a fast intermediate, because
its concentration is all times very, very low!
B.) In the case of side-reactions-steps you as a chemist are “claimed”, as the ratio of the
different reactions-steps will tell you, how much of which product you will earn!
So, you as a Chemist need all your imagination to get a higher, and even higher, yield
of the product of your/other interest! Some times, only 2% side-reactions may flag
the end of all your endeavours, — so be warned, even if it is anyway “one” of the
most interesting “jobs” on Earth!
(But the opposite can also be the absolute “accolade” for a Chemist, to get only,
but 0.3% of that what is of interest!)
As a conclusion you may extract: In Chemistry “the slowest” is nearly all times
of "most interest", even, if not every times identical founded.
The “Thumb” may tell you: As lower as the “Hill of Activation” is, as faster the
corresponding reaction-step may be.
A normal Chemistry-Book will explain you which of your reaction-steps above will be
So I hope You will all times take not the crude colours.