Question

Help please...thanks..

Answer 1

http://screencast.com/t/t9GRMlxXf

Answer 2

@Callisto @Preetha @cwrw238

Answer 3

Is it B?

Answer 4

yeah but how?

Answer 5

yes

Answer 6

i wasn't sure if it was B or D - i had to check some notes!

Answer 7

Rate is the highest at the beginning.. Since the concentration of the reactants is the highest - more no. of effective collision -> higher rate

Answer 8

yup

Answer 9

When the reaction proceeds, the less the reactants are present, the slower the reaction is, and the less of the rate.

Answer 10

but what about c, the rate increases gradually and decreases or become constant

Answer 11

No... that's the graph for concentration of products formed :|

Answer 12

Remember the rate is the highest at the beginning of the reaction. It can't be 0?!

Answer 13

why cannt it be 0, coz its strting from 0.. i mean the rate

Answer 14

Good question. That doesn't make sense to me though...
When you take a look at the graph for concentration of products.
Draw a tangent to the curve at t=0. Slope of tangent = rate of equation
Is it equal to 0?

Answer 15

yup...okay thnks

Answer 16

Huh?!

Answer 17

i mean i understand, rather it wont be 0 :)

Answer 18

I think Kryten is going to give a better explanation :)

Answer 19

rate is only 0 at time 0!!! if you look at any other time than 0 reaction begins, so when time begins to flow reaction begins and at the beginning rate is extremely high cause of excess of reactant which is trying to achieve equilibrium, and as other reactant which is in shortage is depleated reaction slows down, and there are also kinetics involved cause the less of the other reactant you have you must either increase mixing of solution so molecules can come closer to react...

Answer 20

and then finally reaction completes, so the rate of reaction becomes 0

Answer 21

yes

Answer 22

that is why kinetics is important, it isnt enough to have apropreate temperature and pressure if you have molecules far apart so they cant react