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

ChiTCng 7

CROM - SAT - DONG

Bai 38. CROM
A. MUC TIEU BAI HOC
1. Ki§n thii'c
HS biit:
• Vi tri cua crom trong bang tuan hoan, eau hinh electron nguyen tir.
• Tinh chat vat li va tinh chat boa hgc cua crom.
HS hiiu:
• Tai sao eau hinh eiia crom d trang thai ca ban cd 6 electron ddc than.
• Phuang phap san xuat crom.
2. KT nang
• Viet phuang trinh boa bieu dien tinh chat boa bgc ciia crom va hgp chat
crom.
• Giai bai tap ve crom.
3. Tinh cam, thai do
Crom la kim loai HS chi biet qua hgp chat K2Cr207, viec nghien ciiu ve crom
tao himg thu kham pha kien thire mdi.
B. C H U A N B! C U A GV vA HS

• GV: - Bang tuan hoan cac nguyen td hoa hgc.
- Dung eu: Chen sir, dng nghiem, gia thi nghiem, den cdn...
• HS: Xem trudc ndi dung bai hgc.

190


C. TI^N TRJNH DAY - HOC
Hogt dpng cda GV

Hogt dpng cua HS
Hogt dpng I

I. VI TRI VA

CAU

TAO

1. Vi tri cua crom trong bang tuan hoan
GV chieu len man hinh bang tuin hoan HS quan sat bang tuan hoan va nhan xet
yeu cau HS
- Xac dinh sd thir tu eiia crom.

- Crom cd sd thii tu la 24.

- Xac dinh vi tri eiia crom trong bang
- Crom thudc chu ky 4, nhdm VIB ciia
tuan hoan.
bang tuan hoan.
2. Cau tao ciia crom
GV gidi thieu:

HS nghe giang va ghi bai

- Viet cau hinh electron nguyen tir.

- c i u hinh ls^2s^2p^3s^3p^3d^4s'
Cau hinh crom cd sir nhay 1 electron tir

phan ldp 4s sang phan ldp 3d dl ed ciu
hinh ban bao hoa ben.

t i f I f I t i l l [U

- Phan bd eac electron va cae d lugng
tir.
- Nhan xet ve sd ldp e va so e ddc than.

3d-

4s'

- Crom cd 4 ldp electron va 6 electron
ddc than.

- Tir sir phan bd e du doan sd oxi hoa - Trong hgp chat crom cd the ed sd oxi
hoa tir+1 den +6.
cd the ed eiia crom.
GV luu y HS: Trong hgp chat crom cd
sd oxi hoa tir +1 din +6 nhung sd oxi
hoa ben thudng gap la +2, +3, +6.
Hogt dpng 2
II. TINH CHAT VAT LI
GV eho HS nghien ciiu SGK va yeu HS nghien ciiu SGK va nhan xet.
ciu HS neu tinh chit vat li cua crom.

191

Hogt dpng cda GV

Hogt dpng cda HS
Crom la kim loai cd mau tring anh bac, khdi
3

lugng rieng ldn d = 7,2 g/cm , khd ndng
chay t°j.= 1890 C, crom la kim loai cirng
nhat.
Hogt dpng 3
III. TINH CHAT HOA HOC
1. Tac dung voi phi kim
GV thdng bao: Crom ed tinh khir HS viet cae phan iing hoa bgc
manh.
Cr ^ Cr^" + 2e
Cr -^ Cr^" + 3e
Crom tac dung vdi oxi, clo, lim huynh
tao ra crom (III) yeu cau HS viet eac
phan img hoa hgc tren.

4Cr + 3O2 — ^

2Cr203

2Cr + 3CI2 ^ ^

2CrCl3

GV luu y: 0 nhiet do thudng crom cd
ldp oxit ben bao ve (gidng nhdm) nen

khdng tac dung vdi oxi, d nhiet do cao
tac dung dugc nhieu phi kim.

2Cr + 3S ^ ^

Cr2S3

2. Tac dung voi nude
GV cho HS nghien cim SGK va yeu
cau HS giai thich tai sao crom la kim
loai boat ddng nhung trong thuc te lai
khdng tac dung vdi nude.

HS nghien ciiu SGK va nhan xet
Tuy la kim loai boat ddng manh nhung
do cd ldp mang oxit ben bao ve (gidng
nhdm). Nen trong thu te crom khdng tac
dung vdi nude.

3. Tac dung voi axit
GV gidi thieu:
- Crom tan tdt trong dung dich HCl,
H2SO4 loang tao ra mudi crom (II) va
hidro.

192

HS nghe giang va viet phan img hoa hgc

Hogt dpng cda GV
-

Hogt dpng cua HS

Crom khdng tan trong HNO3,

H2SO4 dac ngudi do ed ldp oxit bin
bao ve (bi thu ddng hoa gidng Al, Fe).
Yeu cau HS viet phan irng cua crom
vdi dung dich HCl, H2SO4 loang.

Cr + 2HC1

> CrCl2 + H2

Cr + H2SO4

> CrS04 + H2

Hogt dpng 4
IV. iTNG DUNG
GV chieu len man hinh tranh anh
mieu ta eac img dung ciia crom. Yeu
cau HS nen eac img dung ciia crom.

HS quan sat va nhan xet
Crom ed nhieu img dung trong kT thuat:
- Che tao thep dac biet.
- Dimg de ma bao ve kim loai va tao ve

dep cho dd vat.

Hogt dpng 5
V. SAN XUAT
GV cho HS nghien ciru SGK yeu cau HS nghien eiiu SGK va nhan xet
HS neu phuang phap dieu che crom.
Trong tu nhien crom tdn tai d dang hgp
chat, quang chii yeu ciia crdm la crdmit:
FeO.Cr203.
Phuang phap dieu che chii yeu: Tach
Cr203 ra khdi quang, rdi dimg phuang
phap nhiet nhdm.
Cr203 + 2 Al — ^

2Cr + AI2O3

Hogt dpng 6

CUNG CO BAI VA BAI TAP VE NHA
GV chilu cac bai tap sau len man HS quan sat theo luan cho ket qua
hinh cho HS thao luan cimg cd ndi
dung bai hgc:

13- TKBG HOA HQC 12 NCT2

193


Hogt dpng cua GV
Bai L Cation kim loai M " cd ciu

Hogt dpng cda HS
Bai 1. Chgn dap an A

hinh electron eiia phan ldp ngoai ciing
la 3d". Vay cau hinh electron eiia M la
A. ls-2s-2p^3s^3p^3d^
B. ls-2s-2p^3s-3p^

C. ls-2sV3sV3dV.
D. ls^2s^2p^3s^3p''3d^4s'
Bai 2. Cho phan ung boa hgc sau
Zn + Cr

3+

Bai 2. Chgn dap an C

> Cr^" + Zn^"

Cau nao bieu dien dung vai trd eiia
eac chat tham gia
A. Zn la chat oxi hoa, Cr

la chat khir.

B. Zn" la chat khir, Cr " la chit oxi boa.
C. Cr la chat oxi hoa, Zn la chit khir.
D. Cr" la chat khir, Zn la chat oxi hoa.
Bai 3. Cho 13,5 gam hon hgp eac kim Bai 3. Chgn dap an C

loai Al, Cr, Fe tac dung vdi lugng du
dung dich H2SO4 bang ndng (trong dilu
kien khdng ed khdng khi), thu dugc
dung dich X va 7,84 lit khi H2 (d dktc).
Cd can dung dich X (trong dilu kien
khdng cd khdng khi) dugc m gam muoi
khan. Gia tri cua m la
A. 48,8

B. 42,6

C.47.1

D.45,5

Bai tap ve nha: 1, 2, 3. 4, 5. (SGK)

194


D. HU'ONG
1.

DAN GIAI BAI

TAP TRONG SGK

a) Vi tri ciia crom trong bang he thdng tuin hoan: thudc chu ki 4, nhdm VI B
b) c i u hinh electron nguyen tir: ls^2s^2p^3s^3p^3d^4s'
c) Kha nang tao thanh cae trang thai oxi boa khac nhau cua crom: Do cd

nhieu electron ddc than d cae obitan 3d va 4s nen trong cac hgp chit crom ed
sd oxi hoa biln ddi tir +1 din +6, Trong dd phd biln nhit la eac sd oxi boa
+2, +3, +6.

2.

So sanh tinh chat boa hgc ciia nhdm va crom:
a) Gidng nhau:
- Phan ling vdi phi kim.
- Phan ling vdi axit HC1,H2S04 loang.
- Ben trong khdng khi va khdng phan iing vdi nude.
- Bi thu ddng hoa trong axit H2SO4 va HNO3 dac, ngudi.
Khdc nhau:
- Nhdm ehi ed 1 trang thai oxi boa la +3 cdn crom cd nhilu trang thai oxi
hoa: khi phan ung vdi axit, nhdm cho hgp chit nhdm(III) cdn crom eho
hgp chat erom(II).

3.

- Nhdm cd tinh khir manh ban nen nhdm khii dugc crom (III) oxit.
a) Chgn B: He sd eiia crom trong phan ii-ng la 2.

4.

b) Chgn C: Suat dien ddng chuin cua pin dien hoa la 0,60V. '
Phuong trinh hoa hgc cua phan img nhiet nhdm
Cr203 + 2AI -^ 2Cr + AI2O3

<
' 78

Lugng crom can dieu cbl: — = 1,5 (mol)
^
52
Theo phuong trinh hoa hgc, lugng nhdm cin dimg la: 1,5 mol
Vay khdi lugng nhdm cin diing la: 1,5.27 = 40,5 (gam)
20
5. Lugng crom trong 100 g hgp kim la: — = 0,385 (mol)
80
Lugng niken trong 100 g hgp kim la: — = 1,356 (mol)
Vay lugng niken ung vdi 1 mol crom trong hgp kim nay la:
- i ^ ^ = 3,522 (mol)
0,385

195


Bai 39. MOT SO HOP CHAT CUA CROM
A. MUC TIEU BAI HOC
1. Ki§n thu'c
HS biit:
• Tinh chat hoa hgc dac trung ciia cac hgp chat crom(II), crom(III), crom (VI)
• Ung dung ciia mdt sd hgp chat ciia crom.
HS hieu: Nguyen nhan gay ra tinh oxi hoa manh cua hgp chat crom (VI).

2. KT nang
• Viet phuong trinh hoa bieu dien tinh chat hoa hgc cua crom va hgp chat
crom.
• Giai bai tap ve hgp chat ciia crom.
B. C H U A N B! C U A GV VA HS

• GV: - Bang tuan hoan eac nguyen td hoa hgc.
- Hoa chat: Zn, tinh the K2Cr207, dung dich CrCl3, dung dich HCl,
dung dich NaOH, tinh thi (NH4)2Cr207.
- Dung eu: Chen sir, dng nghiem, gia thi nghiem, den cdn...
• HS; Xem trudc ndi dung bai hgc.

C. T|£N TRiNH DAY - HOC
Hogt dpng ciia GV

Hogt dpng cua HS
Hogt dpng 1

I. HOP CHAT CUA CROM
1. Crom(II) oxit, CrO
GV gidi thieu: Hgp chat Cr(ll) ed sd HS nghe GV gidi thieu.
oxi hoa +2 nen ed tinh khir, de. bi oxi
hoa len sd oxi hoa +3.
GV cho HS nghien ciru SGK va yeu
cau HS neu tinh chat hoa hgc ciia
CrO.

196

HS nghien ciru SGK thao luan va nhan xet
- Crom (11) oxit la oxit baza, ed tinh khu


Hogt dpng cua GV

Hogt dpng ciia HS

CrO +2HC1

-> CrCl2 + H2O

4CrO +O2 - ^

2Cr203

2. Crom(II) hidroxit, Cr(OH)2
GV cho HS nghien ciru SGK yeu eau
HS neu:
^

HS nghien ciru SGK va nhan xet

- Tinh chat vat li eiia Cr(0H)2.

- Crom (II) hidroxit nguyen chat la chat
ran, mau vang, khdng tan trong nude.

- Tinh chat hoa hgc cua Cr(0H)2.

- Cr(0H)2 cd tinh khir de bi oxi khdng khi
oxi hoa theo phan img, de phan huy bdi
nhiet.
4Cr(OH)2 + O2 + 2H2O
Cr(0H)2

> 4Cr(OH)3 *

°""t''''"' > CrO + H2O

- Cr(0H)2 la oxit baza nen
Cr(0H)2 + HCl -> CrCb + 2H2O
-

Phuang

Cr(0H)2.

phap

dieu

che

cua - Dieu che Cr(0H)2 bang each eho mudi
Crom (II) tac dung vdi dung dich kiem.
Cr

2+

20H

-^ Cr(0H)2

3. Muoi crom(II)
GV yeu cau HS du doan tinh chat HS thao luan cho ket qua
ciia hgp chat mudi erom(ll).
- Mudi erom(Il) cd tinh khir manh

2CrCl2 +CI2 ^ 2 C r C l 3
- Mudi crom(ll) cd tinh chat chung ciia
mudi.
CrCl2 + 2NaOH -^ Cr(0H)2^ +2NaCl
CrS04 + BaCl2 -4- CrC^ + BaS04 i
GV yeu ciu HS neu kit luan vl tinh
- Ket luan: Hop chdi crom(n) cd linh khic
chit chung ciia hgp chat crom(ll)
manh.
197


Hogt dpng cda HS

Hogt dpng cda GV
Hogt dpng 2

II. HOP CHAT CROM(III)
1. Crom(III) oxit, CYIOJ,
GV cho HS nghien ciiu SGK va yeu
eau HS neu
- Neu tinh chat vat li ciia Cr203.

HS nghien cim SGK thao luan va nhan xet
- Crom (III) oxit la chat ran mau luc
tham, khdng tan trong nude.
- Cac phan img chiing minh Cr203 ludng

- Viet eac phan img chimg minh tinh.
Cr203 + 6HC1

Cr203 la hgp chat luang tinh.

Cr203

> 2CrCl3 + 3H2O

+2NaOHdac

+

3H2O

>

2Na[Cr(OH)4]
2. Crom(III) hidroxit, Cr(OH)3
HS vilt phuang trinh boa hgc

GV gidi thieu:
- Cr(0H)3 la chat ran ma luc xam,
khdng tan trong nude.

- Cr(0H)3 cd tinh chat tuong tu - Phan ling phan buy
A1(0H)3 yeu cau HS viet cac phan Cr(0H)3 ^
img minh hoa eho tinh chat eiia
- Tac dung
Cr(0H)3 va phan img dieu che
Cr(0H)3 +
Cr(0H)3.

- Tac dung

^

Cr203 + H2O

vdi axit
3HCI -

-> CrCl3 + 3H2O

vdi kiem

Cr(0H)3.+ NaOH

>Na[Cr(0H)4]

- Dieu che
CrCl3 + N a O H ^ ^ Cr(0H)3 + 3NaCl
3. Muoi crom (III)
GV lam thi nghiem: cho mdt it bdt
Zn va dung dich CrC^ lac kT. Sau

198

HS quan sat thi nghiem va nhan xet


Hogt dpng cua GV

Hogt dpng cua HS

mdt thdi gian cho HS quan sat yeu

eiuHS
- Hien tugng: Thay bdt kem tan dan trong

- Neu hien tugng.

dung dich CrC^

- Giai thich.

- Viet phuong trinh boa bgc dang - Giai thich: Do Zn da phan iing vdi dung
dich mudi CrC^ theo phan iing
phan tir va dang ion.
Zn + CrCl3
GV luu y HS: Tuy Zn dimg trudc Cr
trong day boat ddng hoa hgc nhung
3+

Zn + Cr^"

> CrCb + ZnCb
> Cr^" + Zn^"

2+

Zn chi khir dugc Cr thanh Cr .
GV gidi thieu: Mudi NaCr02 bi HS viet phuang trinh boa hgc:

brom oxi hoa trong mdi trudng kiem
tao thanh mudi Na2Cr04 yeu eau HS
viet phuong trinh hoa hgc.

2NaCr02 + 3Br2 + 8NaOH

>

2Na2Cr04 +NaBr + 4H2O
Cr02" +3Br2 +0H" ->Cr04^" +6Br"
+H2O
Hogt dpng 3
III. HOP C H A T CROM(VI)
1. Crom(VI) oxit, CrOj
GV cho HS nghien ciiu SGK va yeu
cau HS neu

HS nghien eiiu SGK va nhan xet

- Tinh chat vat li ciia Cr03.

- Cr03 la chit ran mau dd tham.

- Tinh chit hoa hgc ciia Cr03, viet - Cr03 la oxit axh.
H2O + Cr03
phuang trinh hoa hgc minh hoa.
GV bo sung: Cac axit cua crom ehi
tdn tai trong dung dich, khdng tach
dugc d trang thai tir do.

> H2Cr04
Axit cromic

H2O + 2Cr03 — >

H2Cr207

Axit dieromic

199


Hocit dpng ciia GV

Hogt dpng cda HS
2KOH + 2Cr03

> K2Cr207 + H2O
Kali dicromat

- Cr03 la chat oxi hoa manh.
2Cr03 + 2NH3

'" ) Cr203 +N2 + 3H2O

4Cr03 + 3C - ^ ^ 2Cr203 + 3CO2
2. Muoi cromat va dicromat
GV cho HS quan sat mau tinh the HS quan sat va nhan xet
K2Cr04, K2Cr207 hay (NH4)2Cr207 - Mudi dicromat cd mau da cam
sau dd hoa tan vao nude. Yeu eau HS

- Mudi cromat cd mau vang chanh
neu tinh chat vat li ciia mudi Cr(VI).
- Mudi Cr(Vl) tan tdt trong nude.
GV gidi thieu: Mudi Cr(VI) cd tinh
HS thao luan eho ket qua
oxi hoa manh, dac biet trong mdi
trudng axit mudi Cr (VI) bi khir (Budc 1 viet cac chat san pham, budc 2
thanh mudi Cr (111). Yeu cau HS can bang oxi hoa khir)
hoan thanh cae sa dd phan img sau
K2Cr207 + FeS04 + H2SO4

>

K2Cr207 + 6FeS04 +7H2SO4

>

Cr2(S04)3 +3Fe2(S04)3+ K2SO4 + 7H2O
K2Cr207 + HCl

Cb

K2Cr207 + 14HC1

> 2CrCl3 + SCb
+ 2KCI + 7H2O

K2Cr207 + H2S+H2S04-

+S

K2Cr207 + 3H2S + 4H2SO4

>

Cr2(S04)3 + 3S + K2SO4 + 7H2O
HS quan sat thi nghiem va nhan xet
GV lam thi nghiem:

- Hien lugng:
- Cho 1 it dung dich K2Cr04 dng
Khi eho dung dich HCl vao dung dich
nghiem sau do them vao 1 it dung
K2Cr04 thi dung dich mau vang chuyen
dich HCl va lac nhe.
sang mau da cam (mau dam hon)

200


Hogt dpng cua GV

Hogt dpng ciiu HS

- Cho 1 it dung dich K2Cr207 ong Khi cho dung dich HCl vao dung dich
nghiem sau do them vao 1 it dung K2Cr04 thi dung dich da cam chuyen sang
djch NaOH va lac nhe.
mau vang (mau nhat han)
Yeu eau HS quan sat, neu hien - Gidi thich: trong mdi trudng axit thi
tugng. giai thich, viet phuang trinh mudi cromat chuyen thanh mudi dicromat

hoa hgc xay ra.
va ngugc lai trong mdi trudng baza thi
GV hudng dan HS giai thich va viet mudi dicromat chuyen thanh mudi cromat
(tdn tai 1 can bang giua 2 mudi trong dung
phirang trinh hoa hgc.
dich).
- Phuang trinh hoa hgc
2Cr0f + 2H" <
(mau vang)

> Cr.O;- + H , 0
(mau da cam)

Ho It dpng 4
CUNG CO B A I V A B A I TAP VE N H A
GV nhac nhd HS luu y
- CrO, Cr(0H)2 cd tinh chat ciia oxit
baza va bazo.
- Cr203, Cr(0H)3 cd tinh chat eiia
hgp chat ludng tinh.
- Cr03, H2Cr04, H2Cr07 cd tinh
chat ciia oxit axit va axit.
GV chieu cac bai tap sau len man
-hinh cho HS thao luan cimg cd ndi

HS quan sat theo luan cho ket qua

dung bai hgc:
Bai 1. Nung hon hgp bdt gdm 15,2 Bai 1. Chgn dap an C
gam Cr203 va m gam Al d nliiet do

cao. Sau khi phan img hoan toan, thu
dugc 23.3 gam hon hgp ran X. Cho
toan bd hon hgp X phan img vdi axit
201


Hogt dpng cda GV

Hogt dpng cua HS

HCl (du) thoat ra V lit khi H2 (d dktc).
Gia tri ciia V la
A. 3,36.

B. 4,48.

C. 7.84.

D. 10,08.

Bai 2. Cho day eac chit: Cr(OH)3, Bai 2. Chgn dap an A
Al2(S04)3, Mg(0H)2, Zn(0H)2, MgO,
Cr03. Sd chat trong day cd tinh chit
ludng tinh la
A. 2

B.4

C. 5

D. 3

Bai 3. De oxi hoa hoan toan 0,01 mol Bai 3. Chgn dap an B
CrCb thanh K2Cr04 bing Cb khi ed
mat KOH, lugng tdi thilu Cb va KOH
tuang img la
A. 0,03 mol va 0,08 mol.
B. 0,015 mol va 0,08 mol.
C. 0,015 mol va 0,04 mol.
D. 0.03 mol va 0,04 mol.
Bai tap ve nha 1, 2, 3, 4, 5. (SGK)

D. HU'ONG

D A N GIAI B A I

TAP TRONG SGK

1.

Dua vao ket luan va cac phan img hoa hgc trong SGK dl hoan thanh bai tap.

2.

Viet phuang trinh hoa hgc:
a) K2Cr207 + 3H2S + 4H2SO4 - Cr2(S04)3 + K2SO4 + 7H2O + 3S
b) K2Cr207+14HCl ^

2CrCb - 3Cl2 + 2KCI + 7H2O

c) K2Cr207 + 6FeS04 + 7H2SO4 . > Cr2(S04)3 + K2SO4 + 7H2O + 3Fe2(S04)
Trong eac phan img tren, K2Cr207 la chit oxi hoa, cdn H2S, HCl, FeS04 la
chit khir, H2SO4, HCl la mdi trudng.

202


Phan ling tren la phan iing oxi boa - khir ndi phan tir
Phuong trinh hoa hgc:
(NH4)2 Cr207 -> N2 + Cr203 + 4H2O
Phuong trinh hoa hgc dang phan tir:
K2Cr207 + 3Na2S + 7H2SO4 _^ Cr2(S04)3 + K2SO4 + 3 Na2S04 +7H2O + 3S
Phuang trinh boa hgc dang ion:
Cr^O^ + 3S'-+ 1 4 H " ^ 2 C r ' " + 3 S + 7H20
a) Phuang trinh hoa hgc:
2CrCl3 + 3Cb +16NaOH -^ 2Na2Cr04 + 12NaCl + 8H2O
CrCb la chat khir vi sd oxi hoa ciia crom trong hgp chit nay tang tir +3 len +6
trong hgp chat Na2Cr04
Cb la chat oxi hoa vi sd oxi boa ciia clo giam tir 0 din - L
b) Phuang trinh boa hgc:
2CrCl3 + Zn ^ 2CrCl2 + ZnCl
CrCb la chat oxi hoa, Zn la chit khir.
c) Mudi Cr(III) ed tinh oxi hoa va tinh khii.

Bai 40.

SAT

A.MUCTIEUBAI HOC
1. Kiln thirc

HSbiit:
• Vi tri cua sit trong bang tuan hoan va eau hinh electron nguyen tir.
• Tinh chit vat li, tinh chat hoa bgc va trang thai tu nhien cua sat.
• sit la kim loai boat ddng trung binh, cd nhieu sd oxi hoa.
HS hiiu:
Tai sao sit ed nhilu boa tri? Khi nao thi tao ra sit (II), khi nao tao Fe(III)

203


2. KT nang
• Ren lu\en kT nang; Tir vi tri eiia kim loai suy ra ciu tao va tinh chat.
• KT nang giai bai tap ve sat kim loai.

3. Tinh cam, thai do
Sir da dang tinh chat ciia sat lam phong phu tinh chit boa hgc eiia kim loai tao
hirng thii cho HS khi nghien cim ve linh chat cua sit.
B. C H U A N B! C U A GV VA HS

• GV: - May tinh, may chieu.
- Hoa chat: Dung dich CuCb, dung dich FeCl3, Fe.
- Dung CLi: Ong nghiem, cap dng nghiem. gia dng nghiem.
• HS: .Xem trudc ndi dung bai hgc.
C.TIEN TRiNH D A Y - H O C
Hogt dung ciia GV

Hogt dpng cua HS
Hogt dpng 1

I. VI TRI VA CAU TAO

1. Vj tri ciia sat trong bang tuan hoan
GV yeu eau HS chieu bang tuan hoan HS thao luan cho ket qiia
len man hinh cho HS quan sat yeu cau - Fe d chu ky 4. nhdm VIIIB (phan
lis neu \i tri ciia sat trong bang tuan nhdm phu).
hoan.
- Sat thudc nhdm nguyen td d.
2. Cau tao ciia sat
GV: Tir sd thir tu cua sat la 26 yeu cau
HS

HS thao luan va nhan xet:

- Viet cau hinh electron.

- Cau hinh 26Fe: ls"2s~2p 3s 3p 3d 4s"

- Phan bd cac electron vao obitan.

- Sa dd phan bd electron vao obitan

it t t t t it
3d^

204

4^


Hogt dpng ciia GV

Hogt dpng cua HS

- Du doan kha nang nhudng electron - Tir cau hinh tren => Fe cd cac kha
ciia nguyen tir sat va kit luan tinh chit nang nhudng electron:
ciia sat.
Fe -> Fe" + 2e (3d )
Fe

Fe^" + 3e

(3d')

Khi tham gia phan img hoa hoc. nguyen
tir sat nhudng 2 electron d phan ldp 4s,
khi tac dung vdi chat oxi hoa manh thi
sat nhudng them 1 electron d phan ldp
3d. tao ra cac ion Fe" , Fe .
GV cho HS nghien cim SGK va yeu - Cac dai lugng ciia nguyen tir sat:
cau HS neu mdt sd dai lugng eiia + Ban kinh nguyen tir: 0,162nm
nguyen tii' sat.
+ Do am dien: 1,83
+ The dien cue chuan E" „ , = -0,44V ,
E",.
Fe

,. =+0.77V.
'Fe-

GV chieu len man hinh hai dang cau tao + Ban kinh ion Fe" = 0,076nm
tinh the sat eho HS quan sat.

Fe^" = 0,064nm
Sat dang a kieu lap phuong tam khdi

Sat dang y kieu lap phuong tam dien.

205


Hogt dpng cda HS

Hogt dpng cda GV
Hogt dpng 2

II. TiNH CHAT V A T LI
GV chieu len man hinh cho HS quan HS quan sat va nhan xet
sat mdt mau sat kim loai (hay ed the Sdi la kim loai mau trang hai xam, deo,
eho HS quan sat mdt mau sat kim loai dai, de ren, nhiet do ndng chay kha cao.
da cao sach ldp oxit). Yeu cau HS neu dan nhiet, dan dien tdt.
tinh chat vat li ciia Fe.
GV bd sung:
- Nhiet do ndng chay ciia sat la 1540 C
- s i t ed tinh nhiem tir (bi nam cham
hilt va cd tir tinh).
- sit cd khdi lugng rieng ldn la 7,9
gam/cm (la kim loai nang).
Hogt dpng 3
III. TINH CHAT HOA HOC
1. Tac dung voi phi kim
GV yeu ciu HS xac dinh S la chat oxi a) Tdc dung v&i luu huynh
hoa manh hay yeu? Viet phuang trinh HS nhan xet: S la phi kim boat ddng

hoa hoe eiia S vdi Fe d nhiet dd cao.
trung binh nen phan img vdi Fe tao mudi

sit (II)
-> FeS
Fe
GV nhan xet la phi kim hoat ddng b) Tdc dung v&i oxi
manh d nhiet do cao. Khi oxi tac dung
HS thao luan viet cac phuong trinh hoa
vdi Fe thudng tao ra hdn hgp nhieu hoe
san pham nhu Fe203, Fe304... yeu
-> 2Fe203
cau HS viet cac phuang trinh hoa bgc. 4Fe + 3 0 2
3Fe + 2O2

206

-> Fe304


Hogt dpng cua GV

Hogt dpng cua HS

GV gidi thieu clo la chit oxi boa c) Tdc dung v&i clo
manh yeu ciu HS du doan san phim Vi clo la chat oxi hoa manh nen tao san
va viet phuong trinh boa hgc.
pham la mudi sat (III):
0

0

Fe + Ch

+3

-i

->FeCl3

2. Tac dung voi axit
a) V&i dung dich HCl, H2SO4 loang
GV yeu cau HS nhan xet vl tinh oxi
hoa cua dung dich HCl va H2SO4 loang
tir do du doan san pham eiia phan img
vdi sat, viet phuang trinh boa hgc minh
hoa

HS thao luan va nhan xet
- Tinh oxi hoa ciia axit HCl va H2S04
loang la do ion H ed tinh oxi boa trung
binh. Nen san pham eiia phan iing la
mudi sat(ll) va khi hidro.
- Phuang trinh boa bgc
Fe

+

HCl -^ FeCb + H2

Fe + H2SO4 loang -^ FeS04 + H2
b) V&i dung dich HNO3 vd H2SO4 dgc
GV yeu eau HS nhan xet ve tinh oxi
hoa cua dung dich HNO3 va H2SO4 dac
tir dd du doan san pham cua phan iing
vdi sat, viet phuang trinh hoa bgc minh
hoa

- Tinh oxi hoa cua axit HNO3 va H2SO4
dac la do nguyen td N , S

cd tinh oxi

hoa manh. Nen san pham cua phan img
la mudi sat(III) va san pham khir cua

N"^ s"^
- Phuong trinh boa bgc
2Fe +6H2S04(d)—^Fe2(S04)3 + 3SO2

GV bd sung: Sat gidng nhdm bi thu
ddng hoa (khdng tac dung)

vdi

HNO3, H2SO4 dac ngudi nen ed the
dimg thiing sit dl chuyen chd axit dac
ngudi ndi tren.

+ 6H2O

Fe+6HN03(dac)-^l->Fe(N03)3 + 3NO2
+ 3H2O
Fe + 4HNO3 ^ Fe(N03)3 + NO + 2H2O

207


Hogt dpng ciia GV

Hogt dpng cda HS

3. Tac dung voi dung dich muoi
GV la thi nghiem: Cho mdt bdt sat
vao

HS quan sat thi nghiem va eho nhan xet

dung dich CuCln lac kT yeu cau HS:

- Hien tugng: Thay dung dich CuCl2
nhat mau dan.

- Quan sat

2+

- Neu hien tirgng

- Giai thich: Do Fe khir Cu thanh Cu.
- Viet phuang trinh hoa hgc minh - Phuang trinh hoa hgc

hoa.
Fe + CuCb -^ FeCb + Cu
Fe + Cu^" -^ Fe^" + Cu
GV luu y HS: Sat tac dung vdi dung
djch mudi tuan theo quy tac a .
4. Tac dung vdi nude
GV gidi thieu:

HS nghe giang, ghi bai va viet phuang
- 0 nhiet do thudng sat khdng tac trinh hoa hgc
dung vdi nirdc.
- 0 nhiet dp cao t° > 570'^C thi sit
khu hai nude thanh sat(ll) oxit.

Fe + H2O

- 0 nhiet dp cao t^' < 570^'c thi sit
khir hai nude thanh sat tir oxit (Fe304).

'"'"'""^ ) FeO + H.

3Fe + 4 H , 0

'"^"°"^ > Fe304 + 4H2

HS thao luan va nhan xet

Yeu cau HS viet phan img hoa hgc.

- Sat la kim loai ed tinh khir trung binh.

GV yeu cau HS neu cac ket luan ve
- Tuy vao ban chat ciia chat phan iing va
tinh chal hoa hoc ciia sat.
dieu kien phan img ma sat ed the bi oxi
hoa tao thanh Fe" hay Fe .
Hogt dpng 4
IV. TRANG THAI TU NHIEN
GV cho HS nghien ciru SGK yeu eau
HS nhan xet ve
208

HS nghien ciru SGK va nhan xet


Hogt dpng cua GV

Hogt dpng cua HS

- Ham lugng sat trong vd qua dit.

- Sat chiem khoang 5% khdi lugng vd
qua dat.

- Dang tdn tai ciia nguyen td sit.

- Neu mdt sd quang quan trgng eiia - Trong tu nhien sat tdn tai chii ylu d
dang hgp chat.
sat.
- Mdt sd quang cua sat
+ Quang manhetit (Fe304) hilm ed trong

tu nhien.
+ Quang hematit (Fe203) ed 2 dang
hematit do (Fe203) va hematit

nau

(Fe203.nH20).
+ Quang xederit FeC03
GV gidi thieu them: Sit cdn ed trong
mau, trong cac thien thach chira sit tu + Quang pirit FeS2
do.
Hogt dpng 5

CUNG CO BAI VA BAI TAP VE NHA
GV chieu eac bai tap sau len man hinh HS quan sat theo luan eho ket qua
eho HS thao luan eiing cd ndi dung
bai hgc:
Bai 1. Cation kim loai M cd ciu hinh Bai 1. Chgn dap an A
electron eiia phan ldp ngoai cimg la
3d . Vay cau hinh electron ciia M la
A. ls^2s^2p^3s^3p^3d^4sl
B. ls^2s^2p^3s-3p^3d^
C. ls^2s^2p^3s^3p^4s^3d^
D. lsV2p^3s^3p^3d^4s^4p'.
Bai 2. Hoa tan 16,8g Fe vao dung dich Bai 2. Chgn dap an C
HNO3 thu dugc 4,48 lit khi NO duy

14- TKBG HOA H
209

Hogt dpng cua GV

Hogt dpng cda HS

nhat. Cd can dung dich thu dugc sd
gam mudi khan la
A. 48,4g
C. 54,0g

B. 72,6g
D. 36,0g

Bai 3. Hoa tan bet 0,5g hon hgp Fe va
Bai 3. Chgn dap an C
kim loai M (boa tri 11) vao dung dich
H2SO4 loang thu dugc 1,12 lit khi
(dktc). Kim loai M la
A. Zn

B. Mg

C. Be

D. Ca

Bai 4. Cho hdn hgp Fe va Cu tac dung Bai 4. Chgn dap an C
vdi dung djch HNO3, phan ung xong
•

thu dugc dung dich A chi chiia 1 chit
tan. Chat tan dd la
A. Fe(N03)3

B. Cu(N03)2

C. Fe(N03)2

D. HNO3

Bai tap ve nha: 1, 2, 3, 4, 5. (SGK)

D. HU'ONG
2.

DAN GIAI BAI

TAP TRONG SGK

Khi ddt bdt sat trong binh dung oxi, sau dd dl ngudi rdi cho tilp "vao binh
dung dich HCl, ed the ed cac trudng hgp sau:
Trudng hgp 1: Oxi dii hoac du, sit phan iing hit tao ra oxit Fe304 hoac
Fe203. Cae axit nay tac dung vdi dung dich axit HCl theo phuong trinh hoa
hgc:
Fe203 + 6HCI -^ 2FeCl3 + 3H2O

(1)

Fe304 + 8 HCl ^ 2FeCl3 + FeCb +4H2O

(2)

Truang hgp 2: Oxi phan iing hit, sit du, tao thanh cac oxit sit. Khi cho axit
HCl vao binh xay ra cac phan iing:
Fe (du) + 2HC1 -^ FeCb + H2
210


Phan img cua oxit sit vdi axit nhu cae phan iing (1) va (2).
Neu axit het, Fe chua phan iing hit se tac dung vdi FeCb
Fe + 2FeCb -> SFeCb
3.

Cd the chgn 2 thuoc thir la axit HCl va dung dich kilm NaOH.
Cach lam nhu sau:
- Lay vao moi dng nghiem mdt it bdt kim loai da cho.
- Nhd vao moi dng nghiem mdt it dung dich axit HCl.
0 dng nghiem nao khdng ed hien tugng gi xay ra thi dd la dng nghiem dung
kim loai Ag. Phan iing xay ra d cae dng nghiem cdn lai:
2A1 + 6HCI -^ 2AICI3 + 3H21
Fe + 2HCl ^ FeCb + H s t
Mg + 2HC1 -^ MgCb + H2 T
Nhd tir tir dung dich kilm vao dng nghiem chiia cae dung dich muoi vira thu
dugc. 0 dng nao thiy cd kit tua tao thanh rdi lai tan ra thi dd la dng chiia
mudi nhdm, nhd vay nhan ra kim loai Al:
AlCb + 3NaOH ^ A l ( 0 H ) 3 | + 3 NaCl
Al(0H)3 + NaOH ^Na[Al(0H)4] + 2H2O
0 dng nao thiy xuit hien kit tua mau tring xanh, sau do din din boa nau thi
dd la dng chiia dung dich muoi sit, nhd dd nhan ra kim loai Fe.

FeCb + 2NaOH ^ Fe(0H)2i + 2 NaCl
4 Fe(0H)2 + O2 + 2H2O ^ 4 Fe(0H)3
0 dng nao thay xuat hien kit tiia mau tring khdng bi biln ddi thi do la dng
nghiem chiia dung dich mudi magie, nhd dd nhan bilt dugc kim loai Mg.
MgCb + 2NaOH -^ Mg(0H)2i + 2NaCl

4.

Phuong trinh hoa bgc
Mg + CUSO4 -^ MgS04 + Cu

(1)

Fe + CUSO4 ^ FeS04 + Cu

(2)

Theo bai ra, lugng Mg va Fe tuong ung la: 0,01 mol va 0,02 mol

211


Theo (1) va (2), nlu Mg va Fe phan img hit thi thu dugc 0,03 mol Cu.
Khdi lugng kim loai thu dugc sau phan img la: 0,03.64 = 1,92 (g).
Thue te chi thu dugc 1,88 g kim loai. Chimg td kim loai da cho khdng phan
img het.
Mg ed tinh khii- manh ban Fe nen phan img trudc.
Lugng Cu sinh ra d (1) la 0,01 mol, tuong img vdi khdi lugng 0,64 gam.
Khoi lugng Fe du va Cu sinh ra d (2) la:

1,88 - 0,64 = 1,24 (gam)

Dat lugng Fe tham gia (2) la x
Khdi lugng Fe du la: 1,12 - 56x
Khdi lugng Cu sinh ra d (2) la 64x
Ta cd: (1,12-56x) + 64x= 1,24 -> x = 0,015
Lugng CUSO4 trong 250 ml dung dich da phan irng bet:
0,015 + 0,01 =0,025 (mol)
Ndng do mol cua dung dich CUSO4 da dung la
0,025
0,25

0,1 (mol/1)
58

a) Luang CUSO4 dem boa tan:

= 0,232 (mol) ,
250

0,232
= 0,464 (mol/l)
Ndng do mol eiia dung dich dem pha che la: —
b) Cho dan dan mat sat vao dung dich tren den du, ed cac hien tugng:
- Xuat hien kim loai mau do. Mau xanh ciia dung dich CUSO4 nhat dan.
- Phuang trinh phan tir:
CUSO4 + Fe -^ FeS04 + Cu
- Phuang trinh ion:
Cu^" + Fe -^ Fe^"+Cu
- Ion Cu" la chat oxi boa, Fe la chat khir.

Khdi lugng kim loai sau phan img tang:
(64-56).0,232= 1,856 (g)
212


Bai 41. MOT SO HOP CHAT CUA SAT
A.MUCTIEUBAI HOC
1. Ki§n thiPc
HS biit:
• Tinh chat co ban cua hgp chit sit (II) va hgp chit sit (111).
• Cach dieu ehi Fe(0H)2 va Fe(0H)3.
• Biet img dung va phuang phap dilu cbl mdt so hgp chit sit.
• Nhan biet cac ion Fe , Fe trong dung dich bing phan iing hoa hgc.
HS hiiu:
Nguyen nhan tinh khir, tinh oxi boa eiia cac hgp chit Fe(ll) va tinh oxi boa ciia
hgp chit Fe(Ill).
2. KT nang
• Tir cau tao nguyen tir, phan tir va mire oxi hoa suy ra tinh chit.
• Giau bai tap ve hgp chat sat.
3. Tinh cam, thai do
Hgp chat sat cd nhieu tinh chat mdi la nhu phan iing chuyen tir sit(II) hidroxit
thanh sat (III) hidroxit trong khdng khi... lam tang sir ham tim hieu eiia HS.
B. C H U A N B! CUA

GV v A

HS

• GV: - Hoa chat: Dinh sat, bdt ddng, dung dich HCl, dung dich FeCb, dung
dich NaOH....

- Dung cu: dng nghiem, gia thi nghiem, den cdn...
• HS: Xem trudc ndi dung bai hgc.
C. TI^N TRiNH DAY - HOC
Hogt dpng cua GV

Hogt dpng cua HS
I. HOP

C H A T SAT

(II)

Hogt dpng I
1. Tinh chat hoa hoc ciia hop chat sat(II)
a) Hgp chdt sdt(11) cd tinh khiiGV yeu ciu HS neu eac sd oxi boa HS thao luan cho ket qua
cua sit til- do du doan tinh chat eiia - Sat ed cac sd oxi boa thudng gap la
hgp chat Fe(ll).
0,+2,+3.

213


Hogt dpng cda GV

Hogt dpng cda HS
- Hgp chit sit(II) cd so oxi boa trung gian
nen ed tinh chit boa bgc dac trung la tinh
khir va tinh oxi boa.

GV yeu eau HS neu:

HS nhan xet: Hgp chit sit (II) thudng gap

- Cae hgp chat sat(II) thudng gap.

la FeO, Fe(0H)2, FeCb, FeS04...

- Lay vi du minh boa cho tinh chat
(tinh khir va tinh oxi boa) cho mdi
loai hgp chat tren.

- Tinh khic:
4FeO + 02 - ^ ^

3Fe203

3FeO+10HNO3-^3Fe(NO3)3+NO+5H2O
4Fe(OH)2 + O2 + 2H2O

>4Fe(OH)3

(trang xanh)

(nau)

2FeCb + C b -^•2FeCb
10FeSO4 + 2KMn04 + 8H2SO4 ^
5Fe2(S04)3 + 2MnS04 + K2SO4 + 8H2O
GV nhan manh: Tinh chit dac trung
ciia hgp chat sat(II) la tinh khir giiip

HS luu y.

- Tinh oxi hod:
FeO + H2 ^ ^

Fe + H2O

Mg + FeCb -> MgCb + Fe
GV ed the bieu dien thi nghiem:

HS quan sat GV bieu dien thi nghiem, thao
luan va nhan xet

- TNI: Lay 2ml dung dich FeCb sau TNI: Chit tao thanh la Fe(0H)2 sau do
dd nhd vao dd vai gigt dung dich chuyen sang Fe(0H)3 cd mau nau.
NaOH lac nhe cho HS quan sat su
FeCb + 2NaOH ^ Fe(0H)2+ 2NaCl
bien ddi mau eiia ket tua trong 1-2
4Fe(OH)2 + O2 + 2H2O
> 4Fe(OH)3
phut.
Yeu cau HS cho biet: Chit vira tao
thanh la chat gi tai sao cd sir chuyen
mau? Viet phuang trinh hoa hgc.

214

(trang xanh)

(nau)