Thiết kế bài giảng hóa học 12 (tập 1) phần 2

ChiFcyng 3. AMIN, AMINO AXIT VA PROTEIN
Bai 9. AMIN
A. MUC TIEU BAI HOC
1. Kl§n thLPC

HS biit:
• Dinh nghia, cdng thiic chung, dac diem cau tao danh phap cua cac amin
dien hinh.
• Tinh chat vat li: Quy luat bien ddi do tan, nhiet do sdi ciia cac amin.
• Tinh chdt boa hgc: Tinh baza cua amin, phan iing the d nhan benzen cua
anilin.
HS hiiu:
Nguyen nhan gay ra tinh baza cho cac amin, tai sao anilin khdng lam quy,
phenolphtalein ddi mau?
2. KT nang
• Nhan dang cac hgp chat amin.
• Viet chinh xac cac phuang trinh hda hgc.
• Quan sat, phan tich cac thi nghiem chiing minh ciia amin.
• So sanh lire baza giira cac amin vdi nhau va vdi NH3.
3. Tinh cam, thai do

• Hieu dugc each giai quyet mau thuan giiia cau tao va tinh chat hoa hgc cua
ciia amin tao nen sir himg thii khi giai quyet van de mdi.
• Thay dugc tam quan trgng cac amin trong ddi sdng va san xuat gay hiing
thu cho HS khi hgc bai nay.
B. C H U A N B! CUA GV VA

HS

• GV: - May tinh, may chieu, cac phieu hgc tap.
- Hoa chat: NH3, anilin, metyl amin, nude cat, quy tim, nude brom.

- Dung cu: Ong nghiem, cap dng nghiem, bd gia thi nghiem.
• HS: Xem trudc bai amin.
128


C. TI^N TRINH D A Y - HOC
Hogt dpng ciia HS

Hogt dpng cua GV

Hogt dpng I
I. KHAI NIEM, PHAN LOAI VA DANH PHAP
1. K H A I NIEM, PHAN LOAI
GV chieu len man hinh cac cdng thiic HS quan sat, thao luan:
NH3, CH3NH2, CH3-NH-CH3, (CH3)3N - So sanh
Yeu cau HS: So sanh cau tao ciia NH3
+ Gidng nhau: deu cd N~^(hda tri III).
vdi cac chat cdn lai. Biet cac chat dd la
+ Khac nhau: NH3 cd hidro lien kit vdi
amin tir dd neu khai niem amin?
N, cac chat khac cd gdc hidrocacbon
lien ket vdi N cua NH3.
- Khai niem: Khi thay thi nguyen tir H
trong phan tir NH3 bang gdc hidro
cacbon ta thu dugc amin.
GV yeu cau HS: Lap day ddng ddng cua HS thao luan:
amin no don chiic, mach hd.
Tir cdng thirc amin don gian nhdt
CH5N

—> ddng

dang

cd

dang

CH5(CH2)kN^Ck+,H2k+5N
Dat k+1 = n -> CnH2n+3N (n> 1)
GV: Tuong tu viet cdng thiic tdng quat
ciia cac amin la ddng dang cua C6H7N.

HS: Cdng thiic la CnH2n-5N (n>6)
HS thao luan:

ancol etylic
GV yeu cau HS: Viet ddng phan va ggi CH3-CH2-OH
ten cac chat cd cdng thiic phan tir CH3OCH3
dimetyl ete
C2HeO.
HS thao luan: C4H9N la amin no mach
hd, don chiic.
GV gidi thieu tuong tu C2HeO thi amin CH3-CH2-CH2-CH2-NH2
ciing cd cac ddng phan vi tri nhdm N.
CH3-CH2-NH-CH2-CH3
Yeu cau HS: Viet ten cac amin cd cdng CH3-CH2-CH2-NH-CH3
thiic C4H9N.
CH3-CH(CH3)-CH2-NH2
GV gidi thieu cho HS biet cac chat cd

CH3-CH(CH3)-NH-CH3
cdng thirc

(1)
(2)
(3)
(4)
(5)

129


Hogt dpng cua GV
(1), (4), (7) la amin bac I
(2), (3), (5) la amin bac II

Hogt dpng cda HS
CH3-CH2-N(CH3)2
(CH3)3C-NH2

(6)
(7)

(6) la amin bac III
HS thao luan:
GV luu y: Cdn phan biet bac amin va Bac amin la sd nguyen tir H trong phan
tir NH3 bi thay thi.
bac ancol.
GV: Tir nhung ddng phan da vilt thi
HS: thao luan va nhan xet.

amin cd nhiing d^ng ddng phan nao?

GV yeu cdu: Neu khai niem bac amin.

Amin cd cac loai ddng phan:
- Vi tri nhdm chuc.
- Bac amin.
GV cho HS nghien ciiu SGK va dat vdn HS thao luan va nhan xet amin phan
lam 2 loai thdng dung la:
de traJdi cac cau hdi.
- Cd thi chia amin thanh nhiing loai - Theo gdc hidrocacbon
nao? - Cho vi du minh hga.
+ amin beo: CH3NH2. C2H5NH2...
+ amin thom: CeH H2,
CH3C6H4NH2
- Theo bac amin
+ amin bac mgt: CH3NH2, C6H5NH2
+ amin bac hai: CH3-NH-CH3,
CH3-NH-CeH5
+ amin bac ba: (CH3)3N
Hogt dpng 2
2. DANH P H A P
GV chilu len bang 3.1 (SGK) len man HS quan sat,thao luan dua ra nhan xet
Cd 2 each ggi ten.
hinh cho HS quan sat va yeu cdu:
- Cd bao nhieu each ggi ten?

+ Ten gdc-chiic: cd cau tnic
Ten amin = Ank + yl + amin

130


Hogt dpng cda GV

Hogt dpng cda HS

- Neu quy tac ggi ten amin?

+ Ten thay thi: cd cdu tnic

- Ggi ten cac amin sau day?

Ten amin = Ankan + vi tri + amin

CH3-CH(CH3)-CH2-NH2
(CH3)3C-NH2

+ Ten thdng thudng chi ap dung cho
mgt sd amin.

CH3-NH-C2H5

Vi du: C6H5NH2 anilin

0-CH3-C6H5NH2
GV bd sung: Neu cd nhieu nhdm chiic HS thao luan:
Dimetylamin: CH3-NH-CH3
amin thi them cac tiep dau ngii di, tri...
Vi du: NH2-(CH2)6-NH2

hexametylendiamin

Phenylamin: C6H5NH2
Benzylamin: C6H5CH2NH2

GV chieu len man hinh bai tap len man Hexan-1,6-diamin: NH2(CH2)6NH2
hinh cho HS thao luan
o-metylpheylamin
NH2
Vilt ten Cac amin cd ten sau day:
dimetylamin, phenylamin, benzylamin.
hexan-1,6-diamin, o-metylpheylamin
Etylmetylamin: C2H5-NH-CH3
etylmetylamin.

^ [^"'

Hogt dpng 3
II. TINH C H A T VAT LI
GV cho HS nghien ciiu SGK va yeu cau HS: Nghien ciiu SGK va nhan xet.
HS nhan xet ve:
- Trang thai.
- Trang thai (d nhiet do thudng).
Metylamin, dimetylamin, trimetylamin.
etylamin la chat khi cd mau khai khd
- Trang thai, mau sac, kha nang hda tan chju. Cac amin khac la chat Idng hoac
ran.
cua anilin.
- Giai thich tai sao anilin de lau ngay - La cac hgp chat khdng mau, 4 amin
dau deu tan tdt trong nude, thii tu cac

trong khdng khi thi cd mau den.
amin cd do tan giam theo chieu tang
phan tir khdi.
- Sir bien thien ve do tan.

131


Hogt dpng cua GV

Hogt dpng cda HS
- Anilin la chdt Idng khdng mau sdi d
184°C, it tan trong nude, tan nhilu
trong dung mdi hiiu ca.
- D I lau anilin ngoai khdng khi thi co
mau den do anilin bi oxi khdng khi oxi
hda.

GV nhan xet va bd sung: tat ca cac amin HS quan sat
deu ddc nhu nicotin, anilin...
GV chilu len man hinh bang sau
Chat

C2H50H

C2H5NH2

C3H8

L s

78,3°C

16,6°C

-42°C

va dat vdn dl: Tai sao amin va ancol cd
phan tir khdi xdp xi nhau ma nhiet do
sdi chenh lech nhau rat Idn.
HS thao luan va nhan xet.
GV hudng dan HS giai quylt vdn dl
- So sanh thanh phdn cau tao cua 3 chat - DIU cd phan tii' khdi xdp xi nhau.
tren.
- YIU td nao anh hudng din nhiet do
sdi.
- Tai sao ancol cd nhiet do sdi cao nhat.

- Khac nhau la do:
C3H8 gdm cd C,H khdng cd nhdm chuc
C2H5OH cd nhdm chiic hidroxyl.

C2H5NH2 cd nhdm chiic amin.
- Nhdm chiic anh hudng tdi nhiet do
sdi
- Ancol cd nhdm OH phdn cue nen co
lien ket hidro.
GV: Vay amin cd lien ket hidro hay HS: Theo khai niem vl lien kit hidro
khdng? NIU cd hay so sanh lien ket thi amin cd lien ket hidro.
Lien kit N-H kem phan cue hon lien

hidro cua ancol va amin.
kit 0-H nen lien ket hidro ciia amin
ylu ban lien ket hidro ciia ancol.
132


Hogt dpng cua HS

Hogt dpng cda GV
GV yeu cau HS kit luan vdn dl.

HS ket luan van de:
Amin cd lien ket hidro yeu han ancol
nen cd nhiet do sdi thap ban ancol va
ankan.

Hogt dpng 4
III. CAU TAO PHAN T i j VA TINH C H A T H O A HOC

LCAUTAOPHANTLT
Cdch 1:
GV yeu cau HS len bang viet cdng thirc HS len bang viet cdng thiic cau tao
cau tao va neu dac diem cau triic ciia NH3.
phan tir NH3.

Q
N

/
H

/ \
H
H

NH3 cd cau tao dang hinh thap 1 dinh
la N va 3 dinh cdn lai la H, tren nguyen
tir N cdn cd 1 cap electron tu do (chua
lien ket).
HS len bang viet cdng thiic cau tao
GV gidi thieu cho HS bilt: Amin cd cdu
tao gidng vdi NH3. Yeu cau mdt HS len
bang vilt cdu tao cua metylamin.
dimetylamin, trimetylamin, anilin

/N ,

N

// \

CH3 H

H

metylamin

/I \
^ " 3 CH3 H

dimetylamin

N
/ /
\
CH3 CH3 CH3

N
/ /
H H

trimetylamin

\
C6H5

anilin

GV yeu cdu HS du doan tinh chdt hda HS thao luan va nhan xet:
hgc cua amin.

133


Hogt dpng cda GV

Hogt dpng cua HS

Amin cd cdu tao tuong tu amoniac
- Tinh baza.

- Tinh khir.
- Tinh chat cua gdc hidrocacbon.
Cdch 2:
HS quan sat (nghien cim SGK)
GV chieu hinh 3.2 SGK len man hinh - Cau tao cua amin tuong tu NH3..
(hoac cho HS nghien ciiu SGK) yeu cdu - Tinh chat cua amin tuang tu NH3.
HS nhan xet ve:
+ Tinh baza.
- Cau tao cua NH3 va cac amin.
+ Tinh chat ciia gdc hidrocacbon.
- Du doan tinh chat hda hgc ciia amin.
+ Tinh khir.
Hogt dpng 5
2. TINH C H A T H O A HOC
a) Tinh bazff
GV lam thi nghiem. Nhiing giay quy HS quan sat
vao cac dung dich sau: metylamin, - Hien tugng:
amoniac, anilin. Yeu cau HS quan sat,
+ Ong dung dung djch metyl amin,
neu hien tugng va giai thich.
amoniac quy tim chuyen thanh mau
xanh
+ Ong dung anilin quy tim Ichdng doi
mau
GV dieu khien, hudng dan HS giai - Giai thich:
thich.
Metyl amin va nhieu amin khac khi tan
vao nude phan ung vdi nude tuong tu
NH3 sinh ra ion OH"
>TTT

_i_TI/^

NH3 + H2O <

\

PTiTTT T*" 1 (^TT~

> [NH4] + OH

CH3NH2 + H20 <

> [CH3NH3]
+ 0H'
Vi vay CH3NH2, NH3 lam quy tim hda
xanh.
134


Hogt dpng cda GV

Hogt dpng cda HS

GV bd sung: Anilin va cac amin tham HS ghi bai.
phan ling rat kem vdi nude va tinh baza
cua anilin rdt ylu (ylu hon CH3NH2,
NH3) nen khdng lam quy tim ddi mau
phenolptalein
HS quan sat va nhan xet:

Nhd vai gigt dung dich vao 2 dng - Ong 1 thay anilin hau nhu khdng tan,
nghiem. Ong nghiem 1: dung nude cdt lang xudng day dng nghiem.
dng nghiem 2: dung dung dich HCl. - Ong 2 thay anilin tan.
Yeu cau HS:
Giai thich:
- Quan sat.
+ Anilin hau nhu khdng tac dung vdi
- Neu hien tugng.
nude nen anilin hau nhu khdng tan, nd
tao van due rdi lang xudng day
- Giai thich.
+ Anilin tan dugc trong HCl do cd
phan ling tao ra hgp chat tan trong
nude
C6H5NH2 + HCl ^[CeH5NH3]^Cr
Phenylamoni clorua
GV tiep tuc lam thi nghiem:

GV dat vdn dl: Tai sao amin beo(ankyl HS thao luan giai quyet van de dudi su
amin) lai cd tinh baza manh hon anilin? dieu khien cua GV
GV dilu khiln hudng dan HS giai quylt - Cau tao cua NH3
van de.

Q

y^

/

H

/

H

\

H

- cdu tao cua NH3 giai thich tai sao lai NH3 cdn cd mdt cap electron tu do nen
cd tinh baza ?
cd kha nang nhan proton (H"*^)-> cd
tinh baza.

135


Hogt dpng cda GV

Hogt dpng cda HS

- So sanh cap electron tu do trong NH3 - So sanh NH3 va CH3NH2
va trong ankyl amin (VD: metyl amin).
- So sanh cap electron tu do trong NH3
va trong anilin.

Q

/ /
H H

N
CH3 H

H

H

Do cd gdc ankyl(CH3) cd hieu iing day
electron len N lam cho mat do electron
tu do tren nguyen tir N tang -^ de cho
cap electron tu do nay (de cdng H'*')
hon nen cd tinh baza manh hon NH3.
- Tuong tu vdi NH3 va CeH5NH2 thi
nhdm CeHs cd hieu iing hut electron
cua nhdm NH2 lam giam mat do
electron cua nguyen tir N so vdi mat do
electron trong NH3.

N

,N
H

H

H

H

H

CsH
605

-> lam giam kha nang nhan H'*^ -^ tinh
baza ciia anilin nhd ban cua NH3
GV yeu cau HS ket luan van de.

HS: Tinh baza ciia anilin cd the manh
ban hay yeu hon NH3 tuy thudc vao
gdc hidrocacbon lien ket vdi nita

GV chieu bai tap sau len man hinh cho HS thao luan:
HS thao luan
Chgn dap an C.
Sap xep cac chat sau theo thii tu luc
baza tang ddn NH3, CH3NH2, (CH3)2NH,
CH2=CH-NH2.
A. CH2=CH-NH2, CH3NH2, NH3,
(CH3)2NH
136


Hogt dpng cda GV

Hogt dpng ciia HS

B. NH3, CH3NH2, CH2=CH-NH2,
(CH3)2NH

C. CH2=CH-NH2, NH3, CH3NH2,
(CH3)2NH
D. (CH3)2NH, CH3NH2, CH2=CH-NH2,
NH3
GV: Tuang tu NH3 hay vilt phuong HS thao luan viet phuong trinh hda hgc
trinh hda hgc ciia metylamin vdi dung 3CH3NH2 + 3H2O + FeCl3 -^
dich FeCl3.
3CH3NH3CI + Fe(OH)3i
GV yeu cau HS: Viet phuang trinh hda HS: Phuang trinh hda hgc
hgc chay tdng quat cua day ddng dang „ _ , .
. , 6n + 3 _
2
C
n
H
2
n
+3N+^;—02^
metylamin
2
2nC02 + (2n + 3)H20 + N2
Hogt dpng 6
b) Phdn ling the & nhan tham cda anilin
GV lam thi nghiem:

HS quan sat

Cho vai gigt dung dich Br2 vao 2 dng
nghiem: dng 1 la dung dich metyl amin,
dng 2 la dung dich anilin rdi lac nhe.

Yeu cau HS:

- Hien tugng: Ong nghiem dung dung
dich anilin xuat hien ket tua trang.

- Quan sat
- Neu hien tugng
- Giai thich
- Viet phuong trinh hda hgc

O"

- Giai thich: Tuong tu vdi phenol thi
nhdm -NH2 day electron vao nhan
tham lam giau electron tai cac vi tri
ortho-para nen de dang thay thi
nguyen tir hidro bang nguyen tir brom
tao ra 2,4,6-tribrom anilin
- Phuong trinh hda hgc
NH2

JL
[Q]+3Br2^
^ ^

NH,

JL
^'•"O"^'

+3HBr

^^^(trang)

137


Hogt dpng cda GV

Hogt dpng cua HS
- Metyl amin khdng cd hien tugng
tren.

GV bd sung phan iing nay de nhan bilt
anilin.

HS thao luan.

- Nhdm NH2 ddy electron vao nhan
GV yeu cau HS: Chiing minh sir anh benzen lam tang mat do electron tren
hudng qua lai giiia gdc phenyl vdi nhdm nguyen tir C tai cac vi tri ortho-para -^
de tham gia phan img the brom.
chiic amin.
- Nhdm CeHs hut electron cua nhdm
NH2 lam cho cap electron tu do cua N
bi giii chat ban -^ lam giam tinh baza.
GV gidi thieu cho HS biet cac amin cd
img dung:

HS lang nghe va ghi bai.

- Amin dugc dung trong tdng hgp hiru
CO. Dac biet la cac diamin diing de tdng
hgp polime.
Vi du: Anilin la nguyen lieu trong cdng
nghiep pham nhugm, polime, dugc
pham...
- Dieu che amin cd nhieu each nhu:
+ Thay the nguyen tir H trong phan tir
HS hoan thanh cac sa dd.
amoniac theo sa dd.
NH3

+CH,I
-Hi

-> CH3NH2

(CH3)2NH

+CH3I

^

+CH3I
-Hi

(CH3)3N

-HI

+ Khir hgp chat nitro
CeH5N02

+[H](F^+Hci) ^ CeH5NH3Cl

+ NaOH

^CeH5NH2

GV yeu cau HS hoan thanh cac sa do
tren.

138

CH3I + NH3 -^ CH3NH2 + HI
CH3I + CH3NH2 -^ (CH3)2NH + HI
CH3I + (CH3)2NH -^ (CH3)3N + HI
C6H5NO2 + 7HCldu +3Fe -^
C6H5NH3CI + 3FeCl2 + 2H2O


Hogt dpng cda GV

Hogt dpng cua HS

Hogt dpng 7
CUNG CO B A I V A B A I T A P VE N H A
GV nhac lai cac ndi dung chinh da hgc. HS lang nghe va he thdng kien thirc da
Yeu cau HS luu y cac diem chinh sau:

hgc.
- Khai niem amin.
- Bac amin (phan biet vdi bac ancol).
- Danh phap amin.
- Tinh chat vat li.
- Tinh chat ciia amin la tinh bazo (so
sanh tinh baza cua cac amin vdi NH3),
phan ling the ciia cac anilin.
- Ung dung cua amin.
GV chieu cac bai tap sau len man hinh
cho HS ciing cd.
\. Cd bao nhieu ddng phan la amin bac Dap an A
hai trong cdng thirc C4H9N
A. 3
B.2
C. 1
D.4
2. So amin tham cd cdng thiic phan tir la Dap an C
C7H9N la
A. 2
B.4
C.5
D. 7
3. Sap xep cac amin sau theo tinh baza Dap an B
tang dan
p-CH3CeH4NH2

(1),

p-N02CeH4NH2 -(2),

139


Hogt dpng cua GV
C6H5NH2

(3),

n-CeH,3NH2 (4)
A.(l),(2),(3),(4)
B.(2),(3),(l),(4)
C(4),(2),(3),(l)
D.(2),(4),(3),(l)
4. D I trung hda 25 gam dung dich ciia
mdt amin don chiic X ndng do 12,4%)
cdn diing 100ml dung dich HCl IM.
Cdng thiic phan tir cua X la
A. C3H5N
B. C3H7N
C. CHsN
D. C2H7N
Bii tap ve nha 1, 2 , 3 , 4 , 5 , 6 . (SGK)

D. HU'd/NG D A N GIAI BAI TAP TRONG SGK
1.

Chgn dap an C

2.

Chgn dap an D

3.

Vilt cac ddng phan amin
a)C3H9N: CH3 - CH2 - CH2 - NH2

CH3-CH-NH
CH3
amin bac mdt

Amin bac mdt

CH3

CH3-CH2-NH-CH3

CH3-N-CH3
amin bac hai

Amin bac hai
b) C7H9N
CH2-NH2

NH,

NH-CH3

NH2

I

I

^ ^ " ©IcH.
CH3

140


4. Cac sa dd tach
a)

CH4, CH3NH2
+ ddHadu(l)

CH4 t

dd CH3NH3^Cr, HCl du

CHjNHjt

ddNaCI

b)
JH

NH2

+ dd NaOH
lie deu, chiet

CfiHsONa, NaOH du

C6H6, C5H5NH2
+ dd HCl
lac deu, chiit

+ Sue CO2 du

CfiHsOH

ddNaHC03

CgHe

C6H5NH3CI, HCl du
+ dd NaOH du

C6H5NH2

NaCI

5. a) Dung dung dich axit
b) Dimg giam de khir miii tanh
141


6-

Mc^H,Br3NH, = 330 g

a) Phuang trinh hda hgc
CeH5NH2 + 3Br2 -^ CeH2Br3NH2i + 3HBr
3 mol
330gam
0,04. mol

4,4 gam
0,04.160.100 ,,^ , , ,,
JYl
"
' ^^ ^
Vdd Br33% =

b) Phuang trinh hda hgc
C6HsNH2 + 3Br2 -^ C6H2Br3NH24 + 3HBr
1 mol

330gam

0,02 mol

6,6 gam

^QHsWH, = 0,02.93 = 1,86 gam

Bai 10. AMINO AXIT
A. MUC TIEU BAI HOC

1. KIdn thu'c
HS biit:
• Khai niem, img dung va vai trd amino axit.
• Dua vao dac diem cau tao de suy ra amino axit vira cd tinh axit vira cd tinh
baza.
• Biet dinh nghia, dieu kien monome ciia phan img triing ngung.
HS hieu: Cau tnic phan tir va tinh chat hda hgc ca ban cua cac amino axit.
2. KT nang
• Nhan biet va ggi ten amino axit.
• Viet cac phuang trinh hda hgc ciia amino axit.
• Quan sat, giai thich cac thi nghiem chimg minh.
3. Tinh cam, thai do
Amino axit cd tam quan trgng trong viec tdng hgp ra protein, quyet dinh sir
sdng, khi nam cac tinh chat ca ban cua nd (dinh nghia, danh phap va cac tinh
chdt dac trung ciia nd) se tao himg thii cho HS khi nghien ciiu bai nay.
142


Mdi quan he giiia hgp chdt cd hai nhdm chiic (axit va baza) ddi lap nhau lai tdn
tai trong mdt hgp chdt. Se cd nhiing tinh chdt mdi kich thich sir td md ciia HS
tham gia kham pha.
B. C H U A N Bj CUA

GV VA

HS

• GV: - May tinh, may chieu, cac phieu hgc tap.
- Hinh anh, tranh ve lien quan bai hgc.
- Hoa chat: Quy tim, glyxin, axit glutamic, lysin.

- Dung cu: dng nghiem, cap dng nghiem.
• HS: On tap kien thirc li thuyet, phuong phap giai bai tap ve amin va xem trudc bai amino axit.
C. TI^N TRiNH DAY- HOC
Hogt dpng cua HS

Hogt dpng cda GV
Hogt itong I
KIEM TRA B A I CU

GV chieu ndi dung bai tap len man hinh HS chuan bi bai.
yeu cau 2 HS len bang trinh bay, cac
HS khac chuan bi de nhan xet va bd
sung.
I. De trung hda 25 gam dung dich ciia
mdt amin don chirc X ndng do 12,4%)
cdn dung 100ml dung dich HCl IM.
Cdng thiic phan tir cua X la
HSl:
B. C3H7N
A. C3HsN
mamin=3,lg

C. CHsN

D. C2H7N

2. Cau nao dudi day khong diing?
A. Cac amin deu cd tinh baza

UHCI = namin =

=> Mamin = 31 -^

0,1
D a p ,i n C

HS2 chgn dap an B

B. Tinh amin cua tat ca cac baza deu
manh ban NH3
C. Anilin cd tinh baza ylu hon NH3
D. Tdt ca cac amin don chiic deu chiia
mdt sd le nguyen tu H trong phan
tir.

143


Hogt dpng cda GV

Hogt dpng cda HS
Hogt dpng 2
I. KHAI NIEM

GV chieu len man hinh cua cac amino HS quan sat, thao luan va nhan xet:
axit.
NH2CH2-COOH

CH3-CH-COOH
NH2

HOCO-CH2-CH2-CH-COOH
NH2
Yeu cau HS neu:
- Khai nifm amino axit.
- Cdng thirc tdng quat.

Amino axit la hgp chat hiiu ca tap chiic
ma phan tir chiia ddng thdi nhdm amino
(NH2) va nhdm cacboxyl (COOH).
Cdng thirc tdng quat la:
(NH2)xR(C00H)y (X, y >1)
R la gdc hidrocacbon
HS quan sat, thao luan

GV chieu len bang hinh 3.2 yeu cau HS - Cd 3 each ggi ten amino axit
nhan xet:
+ Ten thay the: Cd cau triic
- Cd bao nhieu each ggi ten amino axit.
axit + vi tri + amino + ten axit
2

- Quy tac ggi ten cua moi each.

1

VD: C H, - C OOH
11 ^
NH2
-

axit-2-amino
etanoic

- Cho vi du.
CH3 - C H - C H - COOH
CH3 NH2
Axit-2-amino-3-metylbutanoic
+ Ten ban he thdng
Xet vi tri tuong ddi ciia nhdm amino
trong mach cacbon.

144


Hogt dpng ciia GV

Hogt dpng cua HS
m

E

6

Y

p

a

C - C - C - C - C - C - COOH
- Quy tac ggi ten
Axit + chii cai vj tri + amino + ten axit
Vi du:
CH2 - COOH axit a-aminoaxetic
NH2
CH3 - CH2 - COOH
NH2
axit a - aminopropionic
HOOCCH2-CH2-CH-COOH
NH2
Axit a-aminoglutamic
Ten thdng thudng khdng theo quy tdc,
+ Ten thay the thi ten axit dugc ggi
ggi theo bang ten rieng.
theo ten thay the.
HS lang nghe va ghi bai.
+ Ten ban he thdng thi axit ggi theo ten
thdng thudng.
GV bd sung:

GV yeu cau HS nam vung cdng thiic
cau tao, cac each ggi ten cua amino axit
thudng gap.nhu:
NH2-CH2-COOH
axit a-aminoaxetic
CH3-CH-COOH
NH2
axit a - aminopropionic
NH2(CH2)5-COOH

axit e-aminocaproic
HCOO-CH2-CH2-CH-COOH
NH2
axit a-aminoglutamic
145


Hogt dpng cda GV

Hogt dpng cda HS

Hoft dpng 3
II. CAU T^O PHAN TU' VA TINH CHAT HOA HQC
LCAUTAOPHANTIT
GV: Viet cdng thiirc cau tag cua
HS thao luan va nhan xet.
NH2-CH2-COOH len bang yeu cduHS NH2-CH2-COOH
nhan xet dac diem cau tao.
- Cd 1 nhdm NH2 cd tinh baza.
- Cd 1 nhdm COOH cd tinh axit.
-> hgp chdt vira cd nhdm axit (tinh
axit), vira cd nhdm baza (tinh baza) s8
tuong tac vdi nhau.
GV hudng dan HS nhan xet
- Dac diem nhdm COOH.
- Dac diem nhdm NH2.
- Sir tuong tac giura 2 nhdm.

HS thao luan va nhan xet: Nhdm
COOH cho proton cdn nhdm NH2 nhan

proton ciia nhdm COOH
NH2CH2COOH <

>
NH2CH2COO"+H'

GV yeu cdu HS du doan tinh chdt vat li NH2CH2COO" + H
cuaamino axit.
GV nhan xet va bd sung:

(

>

NH3^CH2COO"

HS thao luan

- Amino axit khdng bay hoi ndng chay, Do cac amino axit la nhiing hgp chat
ion ludng cue -> a dilu kien thudng la
phan buy d nhiet do tuong doi cao.
- Khdng tan trong dung mdi khdng chat ran ket tinh, de tan trong nude co
phan cue nhu dau hda, benzen, ete...ma nhiet do ndng chay cao (tinh chdt ciia
hgp chat ion).
tan tdt trong nude.
- Amino axit thudng cd vi nggt (mi HS lang nghe va ghi bai
chinh).
Hogt dpng 4
2. TINH C H A T H O A H O C
GV yeu cau HS du doan tinh chdt hda HS thao luan va nhan xet:

hgc ciia amino axit.
146


Hogt dpng cua GV

Hogt dpng cua HS
- Cd nhdm NH2 cd tinh chat cua mdt
baza
- Cd nhdm COOH cd tinh chdt cua mgt
axit-> amino axit cd tinh luong tinh.

a) Tinh chat ludng tinh
GV yeu cdu HS vilt phuang trinh hda HS thao luan va nhan xet:
hgc cua glyxin vdi HCl, NaOH va nit ra - Phuang trinh hda hgc
tinh chdt chung cua amino axit.
NH2CH2COOH + HCl -^
CINH3CH2COOH
NH2CH2COOH + NaOH -^
NH2CH2COONa + H2O
- Kit luan:
+ Amino axit cd nhdm -NH2 nen phan
ling dugc vdi axit vd co manh tao mudi.
+ Cd nhdm -COOH nen phan iing dugc
vdi bazo vo ca tao ra mudi va nude.
b) Tfnh chdt bazar cUa amino axit
GV lam thi nghiem nhiing mdu gidy
quy vao dung dich glyxin, axit
glutamic, Iysin. Yeu cdu HS quan sat
neu hien tugng va giai thich.

HS quan sat, thao luan va giai thich
- Hien tugng:
+ Ong dimg dung dich glyxin quy tim
khdng doi mau.
+ Ong dung dung dich axit glutamic
quy tim hda dd.
+ Ong dimg dung dich lysin quy tim
hda xanh
- Giai thich:
NH2CH2COOH <==> NH3^CH2COOKhdng tao ra H"" hay OH" nen quy
khdng ddi mau

147


Hogt dpng cua GV

Hogt dpng cua HS
H2NC3Hs(COOH)2 <

»

-OOC-C3H5-COO- + tf
>JH3
Tao ra H"^ lam quy ddi mau.
GV nhan xet bd sung amino axit cd Tuong tu glysin tao ra OH" lam quy
cdng thirc (NH2)xR(C00H)y
hda xanh.
Neu X = y quy tim khdng ddi mau.

Neu X > y quy tim khdng hda xanh.
Neu X < y quy tim khdng hda dd.
Hogt dpng 5
c) Phdn iing riing cda nhdm-COOH: phdn img este hoa
GV yeu cau HS viet phan iing este hda HS viet phuang trinh hda hgc.
giira glyxin vdi etahol.
T T Tl T O T T O / ^ /^J T f f~^ J J i'~\T T
H2N-CH2COOH + C2H5OH <

S

•*

NH2CH:COOC2H5 + H2O
GV nhan xet va bd sung:

HS lang nghe va g'

oai.

Thuc ra este dugc hinh thanh dudi dang
mudi Cl^H3^CH2C00C2Hs
Mudn thu dugc este thi:
C1"NH3^CH2C00C2H5 + NaOHvCradc, ->
NH2CH2COOC2H5+NaCl + H2O
GV bd sung:

HS viet phuang trinh hda hgc
- Ngoai ra amino axit cdn cd the tac
CH3CHCOOH + HONO -^

dung vdi HNO2 thi amino axit dugc
NH2
chuyen thanh hidroxi axit. Yeu cau HS
CH3CHCOOH + N2 + H2O
viet phuong trinh hda hgc.
OH
- Phan img nay dugc diing de dinh
lugng nhdm amin trong amino axit
ciing nhu trong protein.

148


Hogt dpng cua GV

Hogt dpng cua HS

GV gidi thieu cho HS:' Ngoai cac tinh HS ghi bai.
chat ciia cac a-amino axit cdn tao vdi
ion ddng vao mdt sd kim lt)ai khac
nhirng mudi ndi phiic mau it tan, rdt
ben.
Hogt dpng 6
d) Phan img triing ngung
GV cho HS nghien ciiu SGK va yeu

cduHS:
- Khai niem phan iing trung ngung.
- Dieu kien de cac amino axit thuc hien

HS nghien ciiu SGK, thao luan va nhan
xet
- Phan ling triing ngung la qua trinh
nhieu phan tir nhd (monome) ket hgp

phan ling triing ngung.

vdi nhau tao thanh phan tir Idn (polime)
- Viet phuang trinh hda hgc phan iing ddng thdi giai phdng nhirng phan tir
nhd nhu H2O.
triing ngung e-amino caproic.
- Dac diem phan img triing ngung amino - Dieu kien de cac amino axit thirc hien
axit.
phan ling triing ngmig la cd tir 2 nhdm
chirc trd len cd kha nang phan img.
- Phuong trinh hda hgc
nH2N(CH2)sCOOH —^
axit s-amino caproic
(-NH-(CH2)5-CO-)„+nH20
Policaproamit
- Dac diem phan img triing ngung
amino axit la nhdm -OH ciia nhdm COOH ciia phan tir nay ket hgp cimg H
chiia nhdm NH2 ciia phan tir kia thanh
H2O va sinh ra polime.
Hogt dpng 7
III. iTNG DUNG
GV cho HS nghien ciiu SGK va yeu HS nghien ciru SGK va nhan xet
cau HS neu nhirng iing dung ca ban cua - Amino axit thien nhien la ca sd kien
tao protein cua co the sdng.
amino axit.

149


Hogt dpng cUa GV

Hogt dpng cda HS
- Mdt sd amino axit dugc dimg pho
biln trong doi sdng nhu muoi mono
sodium glutamat (mi chinh hay bot
nggt) dimg lam gia vi thirc an, axit
glutamic la thuoc bd trg thdn kinh,
methionin la thudc bd gan...
- Axit e-amino caproic, axit co-amino
enantoic la nguyen lieu de san xuat to
nilon.

GV nhan xet va gidi thieu cho HS cdng
thiic cau tao mi chinh (hay bdt nggt).
HOOC-CH2-CH2-CH-COONa
I
NH2
Hoat dpng 8
CUNG CO BAI - BAI TAP VE N H A
GV nhac lai cac ndi dung chinh da hoc HS he thdng lai kien thiic da hgc.
giiip HS ciing cd bai.
- Cdng thiic cua amino axit cd nhdm
NH2 va nhdm COOH.
- Amino axit cd tinh chat ludng tinh,
tinh axit bazo.

- Khai niem ve phan iing trimg ngung.
- Lfng dung quan trgng ciia amino axit
ddi vdi con ngudi.
Bai tap ve nha: 1, 2,3, 4, 5, 6 (SGK)
D. HU'ONG

D A N GIAI BAI

TAP SGK

1. Chgn dap an C
2.

Chgn dap an D

3.

Ggi cdng thiic cua a-aminoaxit X la CxHyOzNt (x, y, z, t e N)
%mo = 100% - (%)mc + %mH + %mN>= 35,96%)
40,45 7,86 15,73 35,96
= 3:7:1:2
X:y:z:t =
16
12
1
14

150

-> Cdng thiic don gian: C3H7NO2
Cdng thiic phan tir: C3H7NO2
Cdng thirc cdu tao H 2 N - C H - C O O H

alanin

CH3
4.

Viet phuang trinh hda hgc
a) CH3 - CH - COOH + NaOH -> CH3 - CH - COONa + H 2O
NH2

NH2

b) 2CH3 - CH - NH2 + H2SO4 -)• |CH3
/^.. - CH
- - - NH3^
-- SO4
COOH
cl.OOH
HCl bao h6a

c)CH3-CH-COOH + CH30H

."^'°^°"°^

CH3-CH-COOCH3 + H2O

NH2 ^

5.

NH2

Viet cac phuang trinh hda hgc cua phan iing triing ngung
nH2N - [CH2]e - COOH

6.

'^"^"^""g > [ HN^CH2)6-CO ]„ + ft-H20

MA = 44,5.2 = 89 (g/mol)
Phuong trinh hda hgc
A + O2 ^

CO2 + H2O + N2

8.9 g

13,2 g

" ^ ^ = - ^ = 3,6(g)

6,3 g

11,2 lit (dktc)

m H = ^ = 0 , 7 ( g ) m N = i ^ = l,4(g)

mo = 8,9 - (3,6 + 0,7+1,4) = 3,2(g)

Cdng thiic phan tir cua A la CxHyOzNt (x, y, z, t e N)

x:y:z:t = M : M : M : l d = o,3:0,7:0,2:0,I = 3:7:2:l
12

1

16

14

-^ Cdng thuc dan gian: C3H7O2N
Cdng thii'c phan tir: (C3H702N)n
M(c\,H,o,N)„ = 89 (g/mol) ^ n = 1. Vay cdng thiic phan tir la C3H7O2N
Cdng thirc cau tao:

O
H2N - CH2 - C - O - CH3

(A)

H2N - CH2 - COOH

(B)

151


Bai 11. PEPTIT VA PROTEIN
A. MUC TIEU BAI HOC

1. Kiln thu'c
HS biit:
•

Peptit, protein, enzim, axit nucleic la gi va vai trd ciia chiing trong co the
sinh vat.

•

Sa luge ve cau true va tinh chat ciia protein.

HS hiiu: Tinh chdt ciia lien kit peptit kem ben trong mdi trudng axit hay bazo.

2. KT nang
• Nhan dang mach peptit.
•

Ggi ten peptit.

•

Viet cac phuang trinh hda hgc ciia protit va protein.

•

Giai cac bai tap hda hgc phan peptit. protein.

3. Tinh cam, thai do
Qua ndi dung bai, HS thdy khoa hgc cd the kham pha dugc nhiing hgp chat cau
tao nen ca the sdng va the gidi xung quanh, ciing cd cho HS niem tin vao khoa

hgc.
B. C H U A N B! C U A GV VA

•

HS

GV: - May tinh, may chieu, cac phieu hgc tap.
- He thdng cau hdi cho bai day.
- Hinh ve, tranh anh lien quan den bai hgc.

•

HS: On tap kien thirc li thuyet, phuang phap giai bai tap ve (amino axit)
va xem trudc bai (peptit va protein).

C. TI^N T R I N H DAY-

HOC

Hogt dpng cda GV

Hogt dpng cua HS
Hogt dpng I
KIEM TRA BAI CU.

GV chieu ndi dung bai tap lea man HS chudn bi bai.
hinh yeu cau 2 HS len bang trinh bay.

152