(Chemical kinetics)
PAGE
40123 3
(Chemical kinetics)
(II)(PbI2) (II)(Pb(NO3)2) (KI) (reaction rate : r) (Chemical kinetics)
(Reactant) (Product)
1 A B1.
(g) (kg)
(L) (dm3)(cm3)
mol/dm3
(s) (min) (hr)
mol/dm3.s mol/s
A B C D
A + B
C + D
r
(
[ ] (mol/dm3) mol
t
+ -
1 mol/s
N2(g) + 3H2(g)
2NH3(g)
aA + bB
cC + dD
a, b, c d A, B, C D
2.
2.1 (Average rate)
2.2 (Instantaneous rate)
(slope) 100s 600s, 200s 500s, 350 350s = ([NO2] / (t
3.
(Rate law) Law of mass action
aA + bB
cC + dD
(1.1) Law of mass action
r ( [A]x[B]y
r = k[A]x[B]yr
k (Rate constant) k Specific rate constant
[A] A
[B] B
x, y A B r = k[A]x[B]y (Rate equation)
(Order of reaction) (x, y) x y (Overall order) 4.
(1.1) r = k[A][B]0 x = 1 y = 0 A B 1 (x + y = 0) A A 2 2 B B r = k[A]
r = k[A][B]2 x = 1 y = 2 3 ( x + y = 3) A A 2 2 B B 2 4 1
2HI H2 + I2r = k[HI]0 = k
2N2O 2N2 + O2r = k[N2O]
CH3CHO CH4 + COr = k[CH3CHO]2
2NO + 2H2 N2 + 2H2Or = k[NO]2[H2]
2NO + Br2 2NOBrr = k[NO]2[Br]
: , 1 , 2548 : 275
1 ()5.
1 2NO(g) + O2(g) 2NO2(g) 25 (C (mol/dm3) NO2(mol/dm3.s)
NOO2
1
2
3
40.01
0.01
0.01
0.020.01
0.02
0.03
0.030.007
0.014
0.021
0.084
1. x, y k2. 3. NO2 NO = 0.04 mol/dm3 O2 = 0.015 mol/dm3
r = k[NO]x[O2]y
.( 1 )
3 ( 1 )
0.021 = k[0.01]x[0.03]y
.( 2 )
4 ( 1 )
0.084 = k[0.02]x[0.03]y
.( 3 )
4 = 2x
22 = 2x
x = 2
1 ( 1 )
0.007 =k[0.01]x[0.01]y
.( 4 )
2 ( 1 )
0.014 =k[0.01]x[0.02]y
.( 5 )
2 =2y
y =1 10.007 =k[0.01]2[0.01]
k =(0.007) / (0.01)3= 7.0 x 103 dm6 mol-2 s-11.x = 2, y = 1, k = 7.0 x 103 dm6 mol-2 s-12. r = k[NO]2[O2]3. r = (7.0 x 103)(0.04)2(0.015)
=0.168mol dm-3 s-1
NO2 = 0.168mol dm-3 s-16.
2 (Collision theory) (Activated complex theory) 6.1 (Collision theory) (Activation energy : Ea)
(a) (b) (c) (d)
4 A B 6.2 (Activated complex theory) (Transition state theory) (Activated complex)
5 A + BC AB + C
A BC (A----B----C) AB C = Ea (E7.
(Endothermic reaction) (Exothermic reaction)
6 (N2 + O2) E1 (NO2) E3 (E E3 E1((E ) Ea E2 E1
7 (N2 + H2) E1 (NH3) E3 (E E3 E1 ((E ) Ea E2 E1 (Ea) ((E) 8. (Reaction mechanism)
5Fe2+(aq) + MnO4-(aq) + 8H+(aq)
5Fe3+(aq) + Mn2+(aq) + 4H2O(l) Fe2+ 5 mol, MnO4- 1 mol H+ 8 mol 14 mol 14 mol (Elementary process) (Elementary reaction)
1. (Unimolecular process) N2O4 2NO2 r = k[N2O4]
2. (Bimolecular process) 2 NO + O2
NO3 r = k[NO][O2]
3. (Termolecular process) 3 2NO + Br22NOBr 3 r = k[NO]2[Br]
(Rate determining step)
2NO(g) + O2(g) 2NO2(g) r = k[NO]2[O2] NO2 O2
2NO(g) + O2(g) 2NO2(g) 3
N2O2 (Intermediate)
r = k[N2O2][O2] N2O2 [N2O2] [N2O2]
[N2O2] r = k[N2O2][O2] r = k.K[NO]2[O2] = k[NO]2[O2]
NO + O2 NO3
(, )
NO3 + NO 2NO2()r = k[NO3][NO] NO3 [NO3]
[NO3] r = k[NO3][NO]
r = k.K[NO]2[O2]= k[NO]2[O2] 9.
8
8 A B 2 A X Ea1(E3 E1) Ea3 X A X B Ea2(E4 E2) Ea4 B X 1 2 1 2 1 1 X A (Ea3 = E3 E2) X B (Ea2 = E4 E2) 1 2 X B (Ea2 = E4 E2) B X (Ea4 = E4 E5) (E (E1 E5)
1
A X
..( )
2
X B
..()10.
10.1 H2 F2 H2 I2
H2(g) + F2(g) 2HF(g)..
H2(g) + I2(g) 2HI(g)
..
10.2
NO2(g) + CO(g)
CO2(g) + NO(g)
NO CO r = k[NO]2 2 CO
NO2 + NO2
NO3 + NO..
NO3 + CO
NO2 + CO2..NO2(g) + CO(g)
CO2(g) + NO(g)
10.3 (Heterogeneous reaction)
Mg(s) + 2HCl(aq)
MgCl2(aq) + H2(g)
Mg HCl HCl Mg Mg
10.4 1
10.5 ()
10 T1 T2 (T2) (Ea) (T1) (Svante August Arrhenius)
(Arrhenius Equation)
k (rate constant)
Ea(kJ/mol)
R = 8.314 J/mol.K
T(K)
A(frequency factor) A
k = Ae-Ea/RT log log k = log A Ea / 2.303RT
(1)
(slope) = Ea / 2.303RT(1) T1 T2 k k1 k2 k
log k1 = log A Ea / 2.303RT1
(2)
log k2 = log A Ea / 2.303RT2
(3)
(3) (2)
log k2 log k1 = (log A Ea / 2.303RT2) (log A Ea / 2.303RT1)
= Ea / 2.303RT1 - Ea / 2.303RT2
= (Ea / 2.303R) (1/T1 1/T2)
Log k2/k1 = (Ea / 2.303R) {(T2 T1)/T1T2}
10.6
(Catalyst) 2
1. (Homogeneous catalyst) I-(aq) H2O2(aq)
2H2O2(aq)
2H2O(l) + O2(g)
I-(aq) 2
1
H2O2(aq) + I-(aq) H2O(l) + IO-(aq)
2
IO-(aq) + H2O2(aq)
H2O(l) + O2(g) + I-(aq)
2H2O2(aq)
2H2O(l) + O2(g)
11 2H2O2(aq)
2H2O(l) + O2(g)
Ea1 1 , Ea2 2 , Ea3 Ea
2. (Heterogeneous catalyst) (Ni) H2 (C2H4)
12 C2H6
(H2 C2H4) (a) H H H H C 2 C2H4 (b, c) C2H6 (d)
(Substrate) (Enzyme substrate complex) (Product)
E + S
ES
E + P
E
S
ES
P
13
14
14 (Ea1) ((E1) (Ea2) ((E2)
(Inhibitor) (H2O2)
2H2O2(l) 2H2O(l) + O2(g)
15
(Ea2>Ea1) ((E)
=
=
( r ) = A = = --
A
([A]
(t
= B = = --
B
([B]
(t
= C = = +
C
([C]
(t
= D = = +
D
([D]
(t
= N2
= 1/3 H2
= 1/2 NH3
=1/c C= +1/c
([C]
(t
=1/d D= +1/d
([D]
(t
r=1/a A=--1/a
([A]
(t
([B]
(t
=1/b B=--1/b
Mg(s) + 2HCl(aq)MgCl2(aq) + H2(g)
=
=
2 NO2
( 3 )/( 2 ) ; =
0.084
0.021
k[0.02]x[0.03]y
k[0.01]x[0.03]y
k[0.01]x[0.02]y
k[0.01]x[0.01]y
( 5 )/( 4 ) ; =
0.014
0.007
3
NO(g) + CO(g) NO(g) + CO2(g)
(E)
N2(g) + O2(g)
2NO(g)
Ea
(E
E1
E2
E3
6 N2(g) + O2(g) 2NO(g)
(E)
N2(g) + 3H2(g)
2NH3(g)
Ea
(E
E3
E1
E2
7 N2(g) + 3H2(g) 2NH3(g)
2NO N2O2 (, )
N2O2 + O2 2NO2()
[N2O2]
K =
[N2O2] = K[NO]2
[NO]2
K =
[NO3] = K
[NO][O2]
[NO3]
[NO][O2]
(E)
E1
E2
E3
E4
E5
A
X
B
Ea4
Ea1
Ea2
Ea3
A B
(E
(a)
(b)
9 (a) (b)
(T2)
(T1)
Ea
T1 > (T2)
k = Ae-Ea/RT
Ea1
Ea2
2
Ea3
(Ea
2H2O2
2H2O + O2
E1
E2
Ea1
Ea2
( E
Ea1
Ea2
(E
PAGE 69.