KINETICS #
ZERO ORDER FIRST ORDER SECOND ORDER
cond-time find gradient > .
rate-conc graph
-
;
aircase
↑
↑I
graph ↓
of reaction
+ find
↳
rate
↳
-
half life :
constant
half life : decreases E
E
E
h= y-intercept
E n= gradient
i
I
- - - -
proportional
--I
-
-
gradient is constant
i
rate doesn't change
·
-
- - -
-
1 as conc .
changes
- - - -
most m
goa ,
>
-
2
>
-
I
3 O -
=I 3
100
----
ist S
3 S
(A) Mol du3 30 90 S
t1 tz Sos
SOS
tz 60s
=
1 ty 30s
= =
=
t 100s +2 So
=
u [A]o = 1 the is constant for Ist order rate = [A] ra
rate
= =
= ↑ [A] -z increases for 2nd order
direcny
half life It) -
time taken for half of the reactant to be used up I s proportional
4 tx2 rate x2
↳ Ax> rate x 3
Ut ratet
↑
RATE = ELA] "[B]" CLOCK EXPERIMENTS
I colorimemy can also be used)
& ↳estimate of inital rate of reaction
only fixed at a
temperature
particular
ASSUMPTIONS : RATE DETERMIN
·
constant temperature
·
cone doesn't change significantly -
#
Mreacts with N to Make O M + N - 28 ·
reaction hasn't proceeded to far
Initial[M]
when the end point is see CoClag) +
Initial IN] Initial rate
Experiment
(Mol cm-3) (Mol dn -3) (mol cm -3s-1)
20 0 1 .
0 2
. O 15
.
IODINE CLOCK REACTION
21 racts
nSocn3](
witthe
0 .
3 02
. 1 35
.
sodium
no more
k =
2 0 4 . 0 3
. . 40
2 thiosulfate
- [blue-black]
b
H202lag) + 2 H+ laq + 21 lay) >
-
2420111 +
12 (99)
[M] [MJ + x3 zed D
I
+ X3 order *
not exp 10 , 21 rate -
stays the ----------
[N] [NJAX1 S rale same O
and im thiosulfateamedicator
wet eXP 21 order
:
21 ,
instantly -
reacts With le product uc -
Co -
() + g
H
rate n[M] 2503" Tag)
(On) CH3
=
+ 12(a) > 21 (99) +
540gaa HsC C
+
-
-1
-an-3s
- -
=as
#xto
>
man >Mdc-
=
1
time taken for
=
mol-1drg- become visible HzC = Clon) -
CHy
OR
"an"st
U2IC-cOION-en
:
Is Mol -
iodine]
-
-
very conc. Of and car
-
vary conc . of H202
time taken for colour
change
RATE DETERM
EVIDENCE FOR SN1 AND SN reachants
lar catalysts
in RDS =
appear in
equati
from
so must
rate e
Ra
I
R Ri #
Mustbe
H C Br Rc Rz
-Y B-
-
4 Br
-
-
-
-
↓ U R3 D
primary secondary tertiary overall
halogeno alone halogenolone halogenvaluate
:
A + B
equation
SN1
NCLEOPHILIC SUBSTITUTION- SN2 -
>
YY 1) NO NO
-u-n-cen
+
SN1-one molecule/ion in RDS
i . ↳ multiple steps 2) N202 +
#
on in SN two molecules lions in RDS rate =
n
↳ only one step
:on R-X + NaOH > ROM -
+ NaX
(CHylz(Br + OH >
-- (
can occur
via two rech
(nyls(Br + On - (CH
-
O
Rate
nBr]( Rate 1 (Br]
[((43) [Br
=
=
RDs > (13)s(
>
-
S - 2) ((n> /z( + + on >
-
1C3
SN ? MECHANISM SNE MECHANISM rate equation =
n[ICUs
ved ats)y(on
which mechanism is m
#+
RDS
OU CHzCHzON Br
-
+
CHzCHzBr >
- +
(Br + Br
M
CH3 Cus
- -
n4
-
1) , = n + BB
I
ins
↓+
L
CU3 CUS
I I
:On 2) Myc- CY
>
-
13) - C -OU
ZERO ORDER FIRST ORDER SECOND ORDER
cond-time find gradient > .
rate-conc graph
-
;
aircase
↑
↑I
graph ↓
of reaction
+ find
↳
rate
↳
-
half life :
constant
half life : decreases E
E
E
h= y-intercept
E n= gradient
i
I
- - - -
proportional
--I
-
-
gradient is constant
i
rate doesn't change
·
-
- - -
-
1 as conc .
changes
- - - -
most m
goa ,
>
-
2
>
-
I
3 O -
=I 3
100
----
ist S
3 S
(A) Mol du3 30 90 S
t1 tz Sos
SOS
tz 60s
=
1 ty 30s
= =
=
t 100s +2 So
=
u [A]o = 1 the is constant for Ist order rate = [A] ra
rate
= =
= ↑ [A] -z increases for 2nd order
direcny
half life It) -
time taken for half of the reactant to be used up I s proportional
4 tx2 rate x2
↳ Ax> rate x 3
Ut ratet
↑
RATE = ELA] "[B]" CLOCK EXPERIMENTS
I colorimemy can also be used)
& ↳estimate of inital rate of reaction
only fixed at a
temperature
particular
ASSUMPTIONS : RATE DETERMIN
·
constant temperature
·
cone doesn't change significantly -
#
Mreacts with N to Make O M + N - 28 ·
reaction hasn't proceeded to far
Initial[M]
when the end point is see CoClag) +
Initial IN] Initial rate
Experiment
(Mol cm-3) (Mol dn -3) (mol cm -3s-1)
20 0 1 .
0 2
. O 15
.
IODINE CLOCK REACTION
21 racts
nSocn3](
witthe
0 .
3 02
. 1 35
.
sodium
no more
k =
2 0 4 . 0 3
. . 40
2 thiosulfate
- [blue-black]
b
H202lag) + 2 H+ laq + 21 lay) >
-
2420111 +
12 (99)
[M] [MJ + x3 zed D
I
+ X3 order *
not exp 10 , 21 rate -
stays the ----------
[N] [NJAX1 S rale same O
and im thiosulfateamedicator
wet eXP 21 order
:
21 ,
instantly -
reacts With le product uc -
Co -
() + g
H
rate n[M] 2503" Tag)
(On) CH3
=
+ 12(a) > 21 (99) +
540gaa HsC C
+
-
-1
-an-3s
- -
=as
#xto
>
man >Mdc-
=
1
time taken for
=
mol-1drg- become visible HzC = Clon) -
CHy
OR
"an"st
U2IC-cOION-en
:
Is Mol -
iodine]
-
-
very conc. Of and car
-
vary conc . of H202
time taken for colour
change
RATE DETERM
EVIDENCE FOR SN1 AND SN reachants
lar catalysts
in RDS =
appear in
equati
from
so must
rate e
Ra
I
R Ri #
Mustbe
H C Br Rc Rz
-Y B-
-
4 Br
-
-
-
-
↓ U R3 D
primary secondary tertiary overall
halogeno alone halogenolone halogenvaluate
:
A + B
equation
SN1
NCLEOPHILIC SUBSTITUTION- SN2 -
>
YY 1) NO NO
-u-n-cen
+
SN1-one molecule/ion in RDS
i . ↳ multiple steps 2) N202 +
#
on in SN two molecules lions in RDS rate =
n
↳ only one step
:on R-X + NaOH > ROM -
+ NaX
(CHylz(Br + OH >
-- (
can occur
via two rech
(nyls(Br + On - (CH
-
O
Rate
nBr]( Rate 1 (Br]
[((43) [Br
=
=
RDs > (13)s(
>
-
S - 2) ((n> /z( + + on >
-
1C3
SN ? MECHANISM SNE MECHANISM rate equation =
n[ICUs
ved ats)y(on
which mechanism is m
#+
RDS
OU CHzCHzON Br
-
+
CHzCHzBr >
- +
(Br + Br
M
CH3 Cus
- -
n4
-
1) , = n + BB
I
ins
↓+
L
CU3 CUS
I I
:On 2) Myc- CY
>
-
13) - C -OU
