Question

here are some questions i did wrong in my university aptitude test prep....all related to the topic 'chemical kinetics'...whoever answers please include your reasoning :)

1)the reactions which proceed at experimental speed (limited speed) are called?
a. fast reactions b. slow reactions c. moderate reactions d.ionic reactions.

2)what is the difference between ''molecularity of a reaction'' and "the order of a reaction"?

Answer 1

For question 1: Limiting speed reactions means that the reaction is sufficiently slow that the reaction rate depends on that step so we need to concern ourselves with speed, ionic reactions just means that the reactants and products are shown as ions when applicable
so that isn't relevant.

So we can exclude d moderate reactions is a term that doesn't apply here as well so we have to deal with slow and fast reactions. if we have a series of reactions slow and fast, which ones would determine the overall rate of our reaction, the slowest reactions will determine our rate. Think of how fast an object could move from one place to another The narrower the region that the object moves through, the slower it can move through.
think of it this way...
if one reaction takes 400 hours for 1 mole to be produced
and the other reactions take 1 second to produce a mole which of those reactions would determine how long it takes for our reaction to occur?
The slowest one takes the longest and thus will have the largest influence on the amount of time it takes for the reaction to occur.

Answer 2

So for question 2: The molecularity of the reaction refers to the number of molecules involved in the slow reaction, the step in the reaction which determines the rate. the reaction order is the exponent in the rate law
so we would have rate = k [A]^order. The molecularity refers to the number of molecules in the slow step of the reaction the order of the reaction is the exponent in the rate law.

Answer 3

Hope I was helpful compared to the other person, good luck with your studies!
All the best! [:

Answer 4

Yes! thanks!