... (a b)
2
= a
2
2ab + b
2
;
(a + b + c)
2
= a
2
+ b
2
+ c
2
+ 2ab + 2bc + 2ca ;
2
1 2 n
(a a a )+ + + =
=
+ + + + + + + + + + + +
2 2 2
1 2 n 1 2 1 3 1 n 2 3 2 n n 1 n
a a a 2( a a a ... (x + y)
2
2xy = a
2
2b
b)
x
3
+ y
3
= (x + y)
3
3xy(x + y) = a
3
3ab
c)
x
4
+ y
4
= (x
2
+ y
2
)
2
2x
2
y
2
= (a
2
2b)
2
2b
2
= a
4
4a
2
b + 2b
2...
...
(a's'k't')
k22n2n
HC
+
+
k
Cl
2
HClxClHC
kk22n2n
+
+
e.Phn ng vi AgNO
3
/NH
3
2
k22n2n
HC
+
+xAg
2
O
3
NH
x
OxHAgHC
2x
xk22n2n
+
+
2) i vi ankan:
C
n
H
2n +2
+ xCl
2
ASKT
C
n
H
2n +2- x
Cl
x
...
M
< ;26
hh sau phn ng cú H
2
d v hydrocacbon cha no phn ng ht
b.Phn ng vi Br
2
d:
k22n2n
HC
+
+
k
Br
2
k2k2n2n
BrHC
+
c. Phn ng vi HX
k22n2n
HC
+...
... 2bc
2
+ c
4
= 2a – 2b
2
+ b
2
- 2bc
2
+ c
4
= 2( a – b
2
) + (b –c
2
)
2
Ta lại có: a – b
2
= - 2(
22 22 22
x yyzzx
) và b –c
2
= - 2( xy + yz + zx) Do đó;
B = - 4(
22 22 22
x yyzzx
) ... 22
x yyzzx
) + 4 (xy + yz + zx)
2
=
22 22 22 22 22 22 2 2 2
44444 488 88( )x y y z z x x y y z z x x yz xy z xyz xyz x y z
Ví dụ 5:
3333...
... AgNO
3
/NH
3
2
k22n2n
HC
+
+xAg
2
O
3
NH
x
OxHAgHC
2x
xk22n2n
+
+
2) i vi ankan:
C
n
H
2n +2
+ xCl
2
ASKT
C
n
H
2n +2- x
Cl
x
+ xHCl K: 1
x
2n +2
C
n
H
2n +2
Crackinh
C
m
H
2m +2
+ C
x
H
2x
... Br
2
d:
k22n2n
HC
+
+
k
Br
2
k2k2n2n
BrHC
+
c. Phn ng vi HX
k22n2n
HC
+
+
k
HX
kk2n2n
XHC
+
d.Phn ng vi Cl
2
(a's'k't')
k22n2n
HC
+
+
k
Cl
2...