Trdn CO so phan tfch kl luong cac n6i dung kien thiic v^ ki nang nam trong khung chuong trinh thi, ca'u true, ma tran d6 thi va cac dang bai tap thucmg gap trong da thi tuyen sinh dai
Trang 1546.076
K600T NGUYEN NGOC OANH CtJ THANH TOAN
K Y T H U A T M d f l GIAINHANHBAITAP
f
B TAP 2 HOA H O C V O C O
^ ^ - Tuyen chon cac ky thuat giai nhanh ve
Trang 2- Tuyen chpn cac ky thuat giai nhanh ve
7 chuyen de hoa v6 ca
- Danh cho hoc sinh Idp 10,11,12 va luyen thi D H - CD
N H A X U A T B A N D A I H O C Q U O C G I A H A N O I
Trang 3L 6 I N O I D A U
Cac ban ddng nghidp va cac em hoc sinh than m6'n!
Trdn CO so phan tfch kl luong cac n6i dung kien thiic v^ ki nang nam
trong khung chuong trinh thi, ca'u true, ma tran d6 thi va cac dang bai tap
thucmg gap trong da thi tuyen sinh dai hoc, cao dang ciia B6 GD - DT, chung
toi da biSn soan tap sach: "Kithudt moi gidi nhanh bai tap Hod hoc"
Cu6'n sach mof ra m6t co h6i cho giao vian va cac em hoc sinh nhin
nhan lai mot each sau sac va toan dien cac da thi tuyan sinh DH - CD ki tii
khi ap dung hinh thiJc thi trac nghiem, tilr do giao vian c6 dinh hirdng dung
dan cho cac em hoc sinh va miic do kien thiic va cac dang bai tap; con cac
em hoc sinh se vihig vang, tu tin hom de di tran con duomg den c6ng truong
Dai hoc ma minh mo udfc
Tac gia cung khdng quan gili gam vao eu6'n sach cac phuong phap giai
hay, giai nhanh, nham giiip cac em ren luyan ki nang giai nhanh cac dang
bai tap trong di thi tuyen sinh DH - CD Cuon sach se la nguori ban d6ng
hanh than thia't vdri cac em hoc sinh trong qua trinh chinh phuc nhiing dinh
cao vinh quang ciia tri thiic; cuon sach se la tai lieu qui cho cac ban d6ng
nghiep trong qua trinh giang day
Da' cuon sach hoan thian hon, ra't mong nhan duoc su dong gop y kia'n
chan thanh ciia cac ban d6ng nghiep va ciia cac em hoc sinh
Chuc cac em dat dirge nhiau thanh tich cao trong cac ky thi sap t6i
Xin tran trong cam cm ! ' *
T A C G I A
Nhd Sach Kkang Viet xin tran trong giai thieu toi Quy doc gid vd xin long
nghe moi y kien ddng gop de cuon sach ngdy cdng hay hon, bo ich hon Thu xin
gtH ve:
Cty TNHH Mot thanh vien - Dich Vu Van Hoa Khang Viet
71- Dinh Tien Hoang, Fhuimg Dakao, Quan 1, TP HCM
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C KI THUAl GSAl NHANH 7 CHUVeN H O A V O C O
C H U Y E N © 1 1 : KT T H U A T ©SAI N H A N H cAc D^m BAI TJSip y g H A L O G E N
A L I THUYI^T
1. DAC D I £ M CIJA CAC NGUVfiN T 6 HALOGEN
ca'u hmh electron 16p
ngoai Cling 2s^2p' 3s^3p' 4s'4p' 5s^-5p' Ban kinh
D6 am dien 3,98 3,16 2,96 2,66
Nang lugmg ion hoa
Nang luong
Nhiat d6 nong chay
Ham iKong (% s6'
Trang 4II TINH CHAT HOA HOC CUA DON CHAT
- Phan ling toa nhiet manh nha't
- Tac dung v<5ri h^u he't kim loai
- Phan ihig toa nhi^u nhiet
- Tic dung vdi hdu he't kim loai
- Phan umg toa nhiet It hon clo
- Tac dung vdri kim loai cf nhiet d6 cao
hoac cin xiic
ZSZ^C, trong bong t6'i
Phan ihig nS
khi chia'u sang hoac dun nong
Phan ling xay ra
F2 +
2NaCl,„^„g (.^ij,,
2NaF + O2
Khir duoc Br , I trong dung djch mu6'i:
CI, +2KBr
^ 2 N a a + Br,
Khu duoc r trong dung dich:
Br, +2NaI 2NaBr +1,
Kh6ng Phan ling
Tinh oxi hoa gi5m dan
Kh6ng dilu che' Cho dung djch H X dSc tac dung vdi chat oxi hoa
(MnO,, PbOj, KCIO3, KMn04, ):
4HX + MnO, X , + MnXj + 2H2O Trong
c6ng nghiep
Dien phan nong
2Naa + 2H,0
-> Cij + H2 + 2NaOH
Sau khi phoi nudrc bien d^
la'y NaCl, ph^n con lai chiia nhidu NaBr:
2NaI + CI, I2 + 2NaCl
1, Trong phong thi nghiem:
4HX<d) + MnO, .0 • * MnX, + X2 + 2 H , 0 16HX(,, + 2KMn04 > 2 K X + 2MnX2 + X , + SH^O 6HX<a) + KCIO3 -> KCl + 3X, + 3H2O
2(vta All) > I, + 2Naa
Trang 5vdi dd
AgNOj Khong
A g C U trdng
A g B r i vang nhat
Agli
vang Tdc dung
voi Si02 SiO^ + 4HF ->
SiF4 + 2H2O Kh6ng phan Ung
Thuc te:
3X2 + 2P + 6H2O — ^ >
6HX + 2H3PO,
V M U O I H A L O G E N U A
Mu6'i florua Mu6'i clorua
( C D
Mu6'i bromua ( B r )
Mu6'i iotua
( D
Ti'nh tan
- D6u tan
(trif CaFj, )
- Da s6' tan (trir AgCl, PbCl,, )
- Da s6' tan (li ij AgBr, PbBr2, )
- Da s6' tan
(triif A g l , Hgl,,
Pbl,, Mnlj) Mu6'i
AgX
Tan, mau trSng
Kh6ng tan, mau trang
Kh6ng tan, mau vang nhat
Kh6ng tan, mau vang
Phan ling vori halogen
iJng vod H,S04 dac
2 H F t + CaS04
r
H C l t + NaHS04
Khong xay ra Khdng xay ra Kh6ng xay ra 2FeCl3 4 2 K I
2 F e a , + 1 ,
+ 2KC1 Phan
- Mu6'i an (NaCl)
- KCl, CaCi,,
NaBr (nude bi^n)
Nal (rong bi^n)
Nhan biet (bang AgN03)
Ag* + I" A g l i
vang
Trang 6- j f ^ CaOCl,
+ H2O
* 3C1, + 6 K O H — ^ 5KC1 + K Q O j + 3 H , 0
* Di6n phan dung dich KCl 2 5 % a n h i a d6 70°C - 75°C
* 6C1, + 6Ca(OH),
— - > Ca(C103), + 5CaCl, + 6 H , 0
Ca(C103)2 + 2KC1 2KC103i + C a a 2
- Kem ben nhifit:
- XiJr ly chat d6c, tinh che' dSu mo
- Thudc n6, ditm
- Diiu che O, trong
phong thf nghidm
B C A C D A N G B A I T A P T R O N G D E T H I T U Y J ^ N S I N H D H - C D
Dang 1: Xdc dinh chat (halogen, muoi halogenua, kim loqi)
* D6' giai cac bai tap dang nay c6 th^ sir dung cac phuomg phap giai nhanh:
Phuong phap xac dinh chat dua vao cong thiirc tinh phan tur khoi: Gia six c6
chat cho electron la A Ta c6:
m
ke -.k
M A ^ ' ne(cho)
Trong do: m^: Khd'i lucmg chat A (gam)
M ^ : Khd'i luong mol chat A (gam) k: s6' electron do m6t nguyen tir A nhucmg n^ (cho)- s6' mol electron do toan bo luong chat A nhircJng \
n^fcho)-+ Tinh gia tri M ^
+ Tir phan tir khoi xac dinh duoc cha^ cin tim f
Phirong phap t r u n g binh: C6ng thiic tinh nguyfin tir kh6'i trung bmh ciia hai
— m
^hh
It
+ Tinh cac luong chat da cho trong bai ra
+ Viet phuong trinh hoa hoc (so d6 hoa hoc) six dung ki hi6u trung binh
+ Tinh dai lucfng trung binh thich hop
+ Rut ra kd't luan va tinh cac dai luong theo ydu c^u
Phuong phap bao toan electron: Trong phan umg oxi hoa khir, t6ng s6' mol electron do chat khir cho phai diing bang t6ng s6' mol electron do chait oxi hoa nhan:
E e (cho) = S e (nhan) n , h „ N , ,ho = n„hj„ N , „^,„
mol nguyen tir chat khir, chat oxi hoa)
N c c h o N , „hj„ \in luot la s6' electron m6t nguyen tur chat khir nhuomg, m6t nguyen tijr chat oxi hoa nhan
+ Viet cac qua trinh oxi hoa, qua trinh khir (kh6ng cin vie't phuong trinh phan
ling oxi hoa - khir)
+ Dat in, dua vao djnh luat bao to^n electron lap duoc phuong trinh dai s6'
Giai he phuong trinh, xac dinh duoc M => chat cin tim
Q
Trang 7- Phuong phap bao loan khoi lucmg: Trong mdt phan ung hoa hoc, tdng khO'i luong
ciia cac cha't san phsim bang long khO'i liromg cua cac chat tham gia phan ling
Gia sir c6 phan ung: aA + bB cC + dD
I h e o djnh luat bao toan kh6'i luong ta c6: niA + nig = nic +
Ap dung: Trong mot phan ung, c6 n cha't {ki ca chat phan ling va san pha'm), n6'u
biet kh6'i luong ciia (n - 1) cha't thi tinh duoc khd'i lucmg cua ch&t con lai
* Mot s6' n6i dung cin chu y:
clorua k i m loai C O hoa tri khac nhau: ' " "
2Fe + 3 a - > 2FeCl3
Fe + 2HC1 -> FeQ, + H ,
- Cac dung dich mudi halogenua nhu mu6'i clorua, bromua, iotua d^u tac dung voi
A g N O j , con muoi florua khong tac dung duoc voi dung djch AgNO,:
NaF + A g N O j : Khong xay ra
NaBr + A g N O j ^ A g B r i + NaNO,
Nal + A g N O , A g l l + NaNO,
V i vay cac bai tap h6n hop mu6'i halogenua tac dung vdri dung dich A g N O j tao
ra ke't tiia cSn chia hai trucmg hop d^ giai
2 Cac t h i d u m i n h hoa:
Thidu 1: Hoa tan hoan toan 1,1 gam h6n hop gom m6t k i m loai kiim X va m6t
k i m loai ki6m thd Y (Mx < My) trong dung djch H C l du, thu duoc 1,12 lit khi
Thidu 2: Cho dung djch chiJa 6,03 gam hdn hop g6m hai mudi NaX, NaY (X, Y
la hai nguyen to c6 trong t u nhien, d hai chu k i lien tiep thu6c nhom V I I A , sd
hieu nguyen tir < Zy) vao dung dich A g N O j (du), thu duoc 8,61 gam ke't
tua PhSn tram khdi luong ciia NaX trong hdn hop ban ddu la
A 47,2% B 52,8% C 58,2% D.41,8%
(Trich De thi tuyen sinh Dai hoc khoi B)
Hu&ng ddn gidi
Trudmg hcrp 1: Hai mudi NaX va NaY d^u tao ke't tiia vdfi AgNO,
Dat cong thiic chung ciia 2 mudi la N a X :
N a X + A g N O j -> A g X 4- + NaNO,
(23 + X ) g ( 1 0 8 + X ) g 6,03 g 8,61 g '
Ta c6: (23 + X) 8,61 = 6,03 (108 + X) X = 178 (khdng c6 halogen nao c6 trong t u nhien ma c6 M > 178 => loai truong hofp nay)
Tru&ng hop 2: X la flo, Y la clo: i
Goi X , y \in luot la sd mol ciia NaF, NaCl
-Theo bai ra, ta c6: 42x + 58,5y = 6,03 (1) ' J 4 i
NaF + A g N O j > khdng xay ra NaCl + A g N O j > A g C U + NaNOj
y y (mol)
Ta c6: 143,5y = 8,61 y = 0,06 (2) TCr ( 1 , 2) ta c6: x = 0,06; y = 0,06
6,03 Dap an diing la D
Thi du 3: Hoa tan hoan toan 6,645 gam hdn hop mudi clorua ciia hai k i m loai
ki^m thudc hai chu ky ke' tiep nhau vao nude duoc dung dich X Cho toan bo dung djch X tac dung hoan toan vdi dung dich A g N O j (du), thu duoc 18,655 gam ke't tiia Hai k i m loai ki6m tren la
A R b v a C s B N a v a K C K va Rb D L i va Na
(Trich de tuyen sinh Cao dang - Khoi A) Hu&ng ddn gidi
K6t tiia la AgCl: sd mol AgCl = = 0,13 (mol) •
K i hieu chung hai mudi clorua la MCI
Trang 8Thi du 4: Di hoa tan hoan loan 6,4 gam h6n hop g6m k i m loai R (chi c6 hoa trj
II) va oxit cua no cdn viira dii 400 ml dung dich HCl I M K i m loai R la
loai R la M g
Dap an diing la
Thi du 5: Cho 1,9 gam h6n hop mu6'i cacbonat va hidrocacbonat cua kim loai
ki^m M tac dung he't v6i dung dich HCl (du), sinh ra 0,448 1ft khi ( 0 dktc)
Thi du 6: Cho k i m loai M tac dung v6i C I , duoc mu6'i X; cho k i m loai M tac
dung vdfi dung dich HCl duoc mu6'i Y Ndu cho kim loai M tac dung vdi dung
dich mu6'i X ta cung duoc mu6'i Y K i m loai M c6 th^ la
Thi du 7: X la kim loai thu6c phan nhom chinh nhom I I (hay nhom I I A ) Cho 1,7 gam h6n hop g6m kim loai X va Zn tac dung vdi luong du dung dich HCl, sinh ra 0,672 lit khi H j (d dktc) Mat khac, khi cho 1,9 gam X tac dung v6i
luong du dung djch H^SO^ loang, thi thi tich khi hidro sinh ra chua d€n 1,12
Thi du 8: H6n hop X g6m M3CO3, MHCO3 va M Q ( M la kim loai ki^m) Cho
32,65 gam X tac dung vijra dii vofi dung dich HCl thu duoc dung djch Y va c6
17,6 gam CO, thoat ra Dung djch Y tac dung vdi dung dich A g N O j du duoc
100,45 gam ket tiia K i m loai M la
A R b B Na C L i D K
Hu&ng ddn gidi
2 44 S6' mol ke't tua AgCl: n^gci = 100,45 /143,5 = 0,7(mol)
Goi X, y , z Idn luot la s6' mol M^COj, MHCO3, M C I trong 32,65 gam X
Bao toan cacbon ta c6: x + y = 0,4 Bao toan clo ta c6: 2x + y + z = 0,7
Ap dung djnh luat bao toan khd'i luong ta c6:
13
Trang 9Thi dti 9: H6n horp X chira dong ihbi hai mu6'i natri cua hai halogen lien tife'p
trong bang tuSn hoan La'y mot luorig X cho tac dung vira dii \6'\0 m l dung
dich A g N O , I M thi thu duoc 15 gam ket tiia C6ng thiJc phan tijf ciia hai muoi
trong X la (cho F = 19; Q = 35,5; Br = 80; I = 127; Na = 23)
A NaF va NaCl B NaBr va Nal
C NaCl va Nal D NaCl va NaBr
Hu&ng dan gidi S6 mol A g N O j : n^gNOj = 0 - ' ("loO •
' Trirorng hop 1: Hai halogen d^u tao diroc kfi't tiia v6i A g N O j
Dat c6ng thufc chung ciia mu6'i la N a X
vay hai mu6'i trong X la NaCl va NaBr
=> "^Agca =0.1.143,5=14,35(gam) ^1.5(gam)
loai tnrcmg hop nay
Thi du 10: Cho 19 gam h6n hop b6t g6m k i m loai M (hoa tri khdng d6i) va Zn
(ti IS mol tirong umg 1,25 : 1) vac binh dirng 4,48 lit khi CI, (dktc), sau cac
phan ufng hoan toaii thu duoc h6n hop chat rSn X Cho X tan h6't trong dung
dich H Q (dir) tha'y c6 5,6 lit khi H , thoat ra (dktc) K i m loai M la
A Na B Ca C M g D A l
Huatng ddn gidi S6'mol khi CI, va H , Mn lirot la: n ^ j = 0 , 2 ( m o l ) ; n^^^ = 0 , 2 5 ( m o l )
Dat X la s6' mol Z n => s6' mol k i m loai M la 1,25x
T a c o : 6 5 x + M.l,25x = 19 ( l ) V ' , ' Theo nguydn t i c bao toan electron ta c6:
Gia tri phii hop la n = 2 => M = 24 (Mg) Dap an diing la C • >
3 Cac bai tap t u luyen:
Cku i : K i m loai nao sau day tac dung voi dung djch HCl loang va tac dung vdi khf
CI3 cho cung loai mu6'i clorua k i m loai?
Cha v.- Phan ling ciia cac kim loai v6i khi CI, va axit HCl:
^ 5 ^ _ F e - i ^ ^ F e C l + H ,
_ ± £ l l _ Cu - t H C ^ Khdng xay ra '
- C ! 2 _ A g — ^ K h a n g x a y r a
FeClj CuCl, « AgCl ^
Trang 10<-C&u 2: Cho m6t lirong don chat halogen tac dung h6't vdd magie thu dirge 19 gam
magie halogenua Cung lugng don chat halogen do tac dung h6t vdi nhom tao ra
17,8 gam nh6m halogenua Kh6'i lirgng don chat halogen da phan ung la
A 8,0 gam B 14,2 gam C 19,0 gam D 7,1 gam
C&u 3: Cho 1,03 gam mu6'i natri halogenua (A) tac dung vdi dung dich AgNO, du
thi thu dirge mot kd't tua, ke't tiia nay sau khi phan iJng hoan loan cho 1,08 gam
bac C6ng thiic ciia mu6'i A la
A NaF B.NaCl C NaBr D Nal
Hu&ng ddn gidi
I no
Sd'molAg: n ^ = — - 0 , 0 l ( m o l )
Dat mu6'i natri halogenua la NaX
PTHH: NaX + AgNOj > AgXi + NaNOj
0,01 < 0,01 (mol) AgX Ag + -X2
C&u 4: Cho dung djch chura 6,79 gam h6n hop g6m 2 mu6i K X , K Y (X, Y m 2
nguydn t<5 c6 trong tu nhifin, 6 hai chu ki lifin tie'p thu6c nhom V I I A , s6' hidu
Zx < ZY) vao dung dich AgNO, dir thu dugc 8,61 gam kd't tiia Th^nh ph^n % kh6'i lugng ciia KX trong h6n hop ban d^u la
Cau 5: M6t h6n hcyp X g6m 3 muoi halogenua ciia kim loai natri nang 6,23g hoa tan hoan toan trong nuoc dugc dung dich A Sue khi clo du vao dung dich A roi c6 can hoan toan dung dich sau phan ung dugc 3,0525g mu6'i khan B La'y m6t nua lucmg mu6'i nay hoa tan vao nude r6i cho phan ihig voi dung djch AgNO, du thi thu dugc 3,22875g ket tiia Tim c6ng thiic ciia cac mu^i va tinh % theo khd'i lugng m6i mu6'i trong X
Hu&ng ddn gidi
Gia sii lugng mu6'i khan B thu dugc sau khi cho clo du vao dung djch A chi c6 NaCl-> n^aci = - ^ ^ = 0,0522 mol '
58,5 *'* NaCl + AgNO, A g a i + NaNO, (1)
* 3 22875
Theo (1) -> n^^ci = "Aga = -2 = 0,045 mol < 0,0522 mol t
Do do, mu6'i khan B thu dugc ngoai NaCl con c6 NaF
Vay trong h6n hgp X chira NaF, khd'i lugng NaF:
Trang 11Goi c6ng thiJc chung ciia hai mutfi halogen c6n lai 1^: NaY
-> ph^i c6 m6t halogen c6 M > 106,11 - » d6 iot • v ^tf
Vay c6ng thiic cua mud'i thiJ 2 Ilk Nal
Dod6c6haitrucmghop: " ' « f-*'
* Tru&ng hop 1: NaF, NaCl vk Nal
Goi a, b Mn lugt la s6 mol ciia NaQ Nal #
6,23
%NaI = 141-100% = 60,19%; %NaF = 6,74%
6,23
C&u 6: Hô tan 1,086 gam mu6'i chiJa oxi ciia clo vdi m6t kim loai ki^m v^o nude,
axit hod dung djch bang axit H2SO4 loang rdi them tiT dung dich K I vao cho dén
khi kh6ng c6n I , thoat ra thi thu duoc 6,096 gam I2 CQng luong mu6'i trdn dem
nhiet phan hoan tôn sau phan ihig con lai a gam mu6'ị
1 Xdc dinh c6ng thiic mu6'ỉ ' ( ' )
2 Tfnhả
Hu&ng đn gidi
1 C6ng thiic mu6'i c6 dang RQO, (x = 1 -> 4)
Phuong trinh phan umg:
Rao, + 2xKI + xH,S04 ^ RQ + xlj + xK,S04 + xH^O
S6' mol I2 = ^ : ^ = 0 , 0 2 4 ( m o l ) Theo phirong trinh s6' mol R Q O , = 0,024
R+35,5+16x = l,086x
0,024 R=29,25x~35,5 Thoa man vdi x = 2; R = 23, kim loai k i i m la Na; mu^i \h NaQỘ
2 Phuong trinh phan umg nhifit phan mu6'i:
.0 NaClOj — ^ NaQ + O,
Theo phuong trinh s6' mol NaQ = s6 mol NaQOj = 0,012
=> Kh6i luong NaQ = 0,012 58,5 = 0,702 g
Cau 7: Cho 50 gam dung dich M X (M la kim loai ki6m, X 1^'halogen) 35,6% tac dung vcri 10 gam dung dich AgNOj thu duoc két tuạ Loc kfít tiia, duoc dung djch nude loc Biét n6ng d6 M X trong dung djch sau thi nghidm giam 1,2 ISn so vdi n6ng d6 ban đụ
mu6i M X la L i a
Trang 12Dang 2: Xdc dinh luffng chat (tham gia, sdn phdm, cdn Iqi sau phan itng)
vd thdnh phan cdc chat trong hdn harp
1 L i thuy^'t v$n dung va phuong phap glai:
* Cac phucfng phap giai nhanh duoc sir dung:
- Phuong phap bao toan electron: Trong phan ung oxi hoa khu, t6ng s6' mol
electron do chat khu ciio phai diing bang tdng s6' mol electron do chat oxi hoa nhan:
S e ( c h o ) = E e ( n h a n ) => iicho-Necho = n„hi:, N,„h,„
+ Viet cac qua trinh oxi hoa, qua trinh khijf (khong cin vie't phucmg trinh phan
ling oxi hoa - khir)
+ Dat ^n, dua vao djnh luat bao toan electron lap duac phuong trinh dai s6'
+ Giai he phircmg trinh, xac djnh cac dai luong theo yfiu ciu ciia bai toan
- Phuong ph^p bao toan khoi luong: Trong m6t phan ung hoa hoc, tdng kh6'i luong
ciia cac chat san ph^m bang t6ng kh6'i luong ciia cac chat tham gia phan ung
A p dung: Trong m6t phan ung, c6 n chat (k^ ca chat phan ung va san ph^m),
- Phuong phap su dung cac cong thurc giai nhanh:
+ C6ng thiic tmh kh6'i luong mu6'i clorua thu ducfc khi hoa tan hit h6n hop kim
loai bang dung dich HCl: m„„,„, = m^i^^,^ + ^ I H H J
+ C6ng thiirc tinh kh6'i luong mu6'i clorua thu duoc khi hoa tan h6't h6n hcyp oxit
* M 6 t s 6 ' c h u y :
- Fe304 khi giai bai tap c6 the qui doi thanh: FeO.Fe^Oj
FejO^ + 8HC1 - > 2FeCl3 + FeCl, + 4 H , 0
Do do h6n horp Cu, Fe304 c6 tha' bi tan hat trong dung djch HCl (Cu khdng tac
dung vdi dung djch HCl nhung bj hoa tan boi dung dich FeClj):
- Mudi clorua bj oxi hoa boi KMn04/H2S04:
- K i m loai Fe (hoac Cr) tac dung voi CU va axit HCl tao ra san ph£m mu6'i clorua
khac nhau: 2Cr + 30, -> 2CrCl3
Cr + 2HC1 CTCXJ + H ,
2 Cac thi du minh hoa: ;
Thidu 1: Cho 42,4 gam h5n hcrp g6m Cu va Fe304 (c6 ti le so mol tuong ung la
c6n lai m gam chat ran Gia trj ciia m la
+) Tuy Cu kh6ng tan trong HCl, nhung bj hoa tan bod FeCl,
— —~— t '
Thi du 2: Hoa tan hoan toan 2,7 gam h6n hop X g6m Fe, Cr, A l bang dung djch HCl du, thu duoc 1,568 lit khi H j (dktc) Mat khac, cho 2,7 gam X phan ling hoan toan vdi khi du, thu duoc 9,09 gam mud'i Khd'i luong A l trong 2,7
gam X la bao nhiau?
A 1,08 gam B 0,27 gam C 0,81 gam D 0,54 gam
(Trich de tuyen sink Cao dang nam 2012 - Khoi A) Hu&ng ddn gidi
Theo bai ra: Hjj^ =0,07 (mol) Goi x,y,z 1& luot la so mol Fe,Cr,Al trong X
Trang 13A1 + - C 1 2
2 ^ z—•l.Sz
Thi du 3: H6n hap X c6 khd'i luong 82,3 gam g6m KQOj, € 3 ( 0 0 3 ) 2 , CaQj va
K Q Nhiet phan ho^n to^n X thu duoc 13,44 lit O2 (dktc), chat ran Y g6m
CaQz va K C l Toan b6 Y tac dung vira du vdi 0,3 lit dung djch K2CO3 IM thu
duoc dung dich Z Luang K C l trong Z nhi^u ga'p 5 15n luong K C l trong X
PhSn tram khd'i luong KCl trong X la
A 18,10% B 12,67% C 29,77% D 25,62%
(Trick dSthi tuyen sink DH khoi A) Hu&ng ddn gidi
Phuong phap bao toan kh6'i luong:
Theo bai ra: = 0,6 (mol); nK2C03 = 0,3 (mol)
Sodd phan utig: X '° > Y + Oj
Theo dinh luat bao toan khd'i luong ta c6:
fhi du 4: D6't 16,2 gam hOn hop X g6m Al va Fe trong khi CI2 thu duoc h6n hop
chat ran Y Cho Y vao nude du, thu duoc dung dich Z va 2,4 gam kim loai
Dung dich Z tac dung duoc vdfi t6i da 0,21 mol KMn04 trong dung dich H2SO4 (kh6ng tao ra SO2) Phdn tram khd'i luong ciia Fe trong h6n hop X la
Thidu 5: D6t chay hdn hop g6m 1,92 gam Mg va 4,48 gam Fe vdi h6n hop khi
X g6m clo va oxi, sau phan dug chi thu duoc h6n hop Y g6m cdc oxit va mu6'i clorua (khdng c6n khi du) Hoa tan Y bang m6t luong vfira dii 120 ml dung dich HCl 2M, thu duoc dung dich Z Cho AgNOj du vao dung dich Z ,
thu duoc 56,69 gam kd't tia Phin tram th^ tfch ciia clo trong h6n hop X la
A 51,72% B 76,70% C 53,85% D 56,36%
(Trich di thi tuyen sink DH khdj B) Hu&ng ddn gidi ^ Se> mol cac cha't: n^^ = 0,08 (mol); np^ = 0,08 (mol); nna = 0,24 (mol)
Goi x, y, z Idn luot la s6' mol ciia Cl2,02 va Ag"^ (tao ra Ag) I*' Cac qua trinh nhucmg nhan electron:
Trang 14Thidu 6: Cin t6'i thi^u bao nhidu gam NaOH (m,) va (mj) de' phan ling hoan
tokn vdi 0,01 mol CrQj Gia tri cua m, va mj iSn luot la
ChU v.- mat ly thuye't c6 thi c6:
14NaOH + 2CrCl3 + 3CI2 ^ 12NaCl + Na2Cr207 + 7H2O
0,07 < - 0,01 0,015(mol)
=> m, = 0,07.40 = 2,8(g); m2 = 0,015.71 = l,065(g)
Thi du 7: Cdn a mol K^CrjO, va b mol HCI d^ diiu che' duoc 3,36 lit di^u
kifin chudn Gia tri a v l b iSn lirot la
Thi du 8: Cho m gam h6n hop X g6m FeO,Fe203,Fe304 vao m6t luong vira du
dung djch H Q 2M, thu diroc dung dich Y c6 ti 16 s6' mol Fe^"" va Fe^^ la 1: 2
Chia Y thanh hai ph^n bang nhau C6 can phSn m6t thu duoc m, gam mu6'i khan Sue khi clo (du) vao phfo hai, c6 can dung dich sau phan ling thu duoc
m2 gam mu6'i khan Bid't mj - m, = 0,71 Th^ tich dung djch HCI da dung la
Ta c6: n^^c\2 = "FeO = x (mol); npecij = 2nFe203 = 2y (mol)
=>nFeCi2 :"FeCi3 = 1:2 => X : 2y = 1:2 =>x = y
CI2 + 2FeCl2 2FeCl2
x / 4 < - x / 2 x / 2 TheobMra: m j - m , =0,71
Thi du 9: Cho 3,16 gam KMn04 tac dung voi dung dich HCI dac (du), sau khi
phan ling xay ra hoan toan thi s6' mol HCI bi oxi hoa la
A 0,10 B.0,16 C.0,02 D 0,05
(Trich de tuyen sinh Cao dang khoi A)
Theo b l i ra: n KMn04 = = 0,02 (mol)
Hu&ng ddn gidi
3J6
158
25
Trang 15Cdchl: Bao toan electron
Cdchl: Sir dung phuong trinh ion rut gpn:
+ Bj oxi hoa (chat khijr): 2C1 -> Clj + 2e
+ M6i tnrcmg (tao mu6'i clorua)
Do do kh6ng ti'nh diroc luong H Q bi oxi hoa theo phucfng trinh phan ling dang
phan i\X
Thi du 10: Didn phan dung dich CuQj voi difin cue tro, sau m6t thoi gian thu
duoc 0,32 gam Cu b catot va m6t lucfng khi X b anot. HSfp thu hoan toan
lugtng khf X tr^n vao 200 ml dung dich NaOH (d nhiet d6 thucmg) Sau phan
ung, ndng d6 NaOH con lai la 0,05M (gia thie't th^ tich dung dich kh6ng thay
ddi) N6ng d6 ban ddu ciia dung dich NaOH la
=> T6ng s6' mol NaOH ban ddu:
2^nN,OH (bandiu) = HNaOH (p/x) + "NaOH (du) = 0,01 + 0,01 = 0,02 (mol)
0,02 Vay n6ng do ban ddu ciia dung dich NaOH: CN,OH (ban d4u) =
Dap an diing la C
0,2 = 0,1M
3 Cac bai tskp tu luyen:
C&u 1: Cho 2,13 gam h6n hop X g6m ba kim loai Mg, Cu \k A l 6 dang b6t tac
dung hoan toan \cn oxi thu dugc h6n hop Y g6m cac oxit c6 kh6'i luong 3,33
gam The' ti'ch dung dich HCl 2M vifa dii d^ phan umg he't voi Y la
= > HHCI = n ^+ = 0,15 (mol) , _
vay: HO = ^ = 0,075 lit = 75 (ml)
Dap an diing la C
C^u 2: Di hoa tan hoan toan 2,32 gam h6n hcpfp g6m FeO, Fe304 v^ FcjO, (trong
do s6' mol FeO bang s6' mol Fe^O^), cSn diing vita dii V lit dung djch H Q I M
Gia trj cua V la
A 0,08 B.0,16 C.0,18 D 0,23
(Trich De thi tuyen sinh DH khoi A) Hu&ng ddn gidi
V i s6' mol FeO bang s6' mol FcjOj ndn qui d6i h6n hap thanh Fe304 (FeO.FcjOj):
S6 mol Fe304: np,304 = ^ - 0,01(mol) ^
PTPIT: Fe304 + 8HC1 > FeCl^ + 2FeCl3 + 4H2O
0,01 -> 0,08 (mol) Suy ra th^ ti'ch dung djch HCl cSn dung: V,<,„c, = ^ = 0,08 (lit) ' E>ap an diing la A