Question

using the concentration and rate data in the table answer questions about the hypothetical reaction

Answer 1

51)
a) I would expect this reaction to be a multi step reaction, based on the overall reaction because all the reactants isn't present in the rate equation.

b) Comparing lines 1 and 2: you doubled A and the rate is the same. So A is zero order.
Comparing lines 1 and 3, you doubled B and the rate is doubled. So B is first order.
Comparing lines 1 and 4, you doubled everything and the rate octupled (i.e. x8). We know doubling A has no effect, and doubling B would double the rate. This leaves a factor of 4 unaccounted for, which we conclude is the effect of doubling C. Since doubling C gives 4x the rate, C is second order.

c) The overall order of the reaction is 0+1+2 = 3.

d) The rate law is rate = k(B)(C)^2.

e) The rate law doesn't depend on A. This means A is not part of the rate-determining step of the reaction. So it must be involved in another step of the reaction. Therefore, there are at least 2 steps in this reaction.

f) Tripling A should have no effect according to the rate law. Doubling B would by itself double the rate, and tripling C would by itself multiply the rate by 9. The combined effect is to multiply the rate by 18 (= 2 x 9). The expected rate is 18 x 3.6x10^-2 = 0.648 = 6.5x10^-1(rounded to 2 significant figures).

g) This is the hardest part, definitely.
step 1: A + A <==> D
step 2: C + C <==> E
step 3: B + E ---> F
step 4: F + D <==> G the product
Note: other mechanisms are possible. I don't really like the idea of A reacting with itself to form D, but if I didn't include it, there is no step 1 and then the second step is rate-determining.

h)

Is what I got so far. Are they correct? also not sure how to answer part h.

Answer 2

o.o confuses me... tag @ganeshie8 and he will just make the things look good !! lol

Answer 3

@DangerousJesse Do You know this one to help this person of your age ?

Answer 4

first we should calculate the rate law :[A]^a *[B]^b * [C]^c = rate
in the other word we should calculate a b and c
take a look table
when the molarity of B and C are stable and [A] in line 3 goes to 1/2 [A] in line 2 rate goes to be
two times bigger so
line 2 /line 3-----> 1/2=[(2)^a ] ----->([B] and [C] are stable so those are not important)
----------> a = -1
in line 1 and 3 [A] and [c ] are stable - [B]in line 1 = 1/2 [B] in line 3 and rate inline 3 is 2 times bigger so line 1/ line 3 -> 1/2 =(1/2)^b ---------> b= 1
and at last in line 2 and 4 [A] and [B] is constant and [C] in line 2 = 1/2 [C] in line4
rate in line 2/ rate in line 4=3.6 * 10^-2 / 290 *10 ^-2 -> c =3

because a and b and c are not 1 and 2 and 4 (in reaction) it is a multi-step reaction
The overall order = -1+1+3 = 3

Answer 5

You seem to have gotten everything right, but I can't help much with H, sorry.

Answer 6

it's ok thx though

Answer 7

wish someone could help with H

Answer 8

Try PMing one of the chemistry wizards, like @chmvijay.

Answer 9

this is rather abstract but we basically want the 3rd step to be termolecular and we want the overall stoichiometry to match, for g) i think something like this is valid:

Step 1: \(A+C\rightleftharpoons AC\)
Step 2: \(AC+C\rightarrow ACC\)
Step 3: \(2B+C\rightleftharpoons 3D\) (rate-determining step)
Step 4: \(ACC+D\rightleftharpoons ACCD\)
Step 5: \(ACCD+C\rightarrow E\)

This adds up to: \(A+2B+4C\rightarrow 2D+E \)

for h) you want to show that the potential energy of the products is higher than the reactants, you also want to show an activated complex (transition state) and all the intermediates.