540.76

PGS.TS. CAOCL/GlAC

B452D

Tai lieu danh cho:
Hoc sinh gioi va chuyen hoa hoc
• Sinh vien sa pham hoa hoc
Giao vien day boi dUSng hoc sinh gioi hoa hoc

V

11

1
NHA XUAT BAN DAI HOC QUOC GIA HANOI

B6I Dciam HQC svfH (abi

Tai lieu danh cho:
Hoc sinh gioi va chuyen hoa hpc
Sinh vien sU pham hoa hpc
Giao vien day boi di/6ng hpc sinh gioi hoa hpc

.30!! .

i -

THi/

1

NHA

jim

BhlH

JHvk^

JAT BAN DAI HOC QUOC GIA HA NQI

T::Ty^L\ini-i mi v uvvn

Jji not dAu

Chuxrnq

1:

M O T S OP H U O N G PHAP

gicvi t u n h i e n n h u t i m h i e u c a u t a o cac chat t h i f c f n g g a p t r o n g c u o c s o n g va d u
d o a n , g i a i t h i c h cac t i n h c h a t cua c h u n g . C u n g c o e m thi'ch l a m cac t h i n g h i e m n h o
de t u n h i e u va chiVng m i n h cac h i e n tUOng r o i n i t ra q u y l u a t . N h i e u e m c 6 t r i nhci
dac biet ve sU p h a n loai cac chat va t i n h chat ciia c h i i n g , t h e h i e n sU sang t a o va
t h o n g m i n h t r o n g each g i a i b a i t a p , . . . T u y n h i e n , cac e m m u o n p h a t t r i e n dUOc
k h a n a n g t U d u y ciia m i n h v e m o n h o a h o c t h i c a n p h a i duOc t r a n g b i m o t each c 6
he t h o n g t i f l y t h u y e t d e n k l n a n g g i a i b a i t a p va cac ufng d u n g thUc h a n h p h u h o p
v 6 i sU p h a t t r i e n n h a n thufc ciia lila t u o i h a o h i i n g va p h a n khcVi nay.
D e g i i i p giao v i e n , p h u h u y n h va h o c s i n h bac t r u n g h o c cO -id ccS t h e m t U l i e u
b o i dUc^ng h o c s i n h g i o i m o n h o a h o c , c h i i n g t o i b i e n soan b o sach " B o i ditofng
h o c s i n h g i o i H o a h o c " t h e o cac n o i d u n g sau:

GIAI

BAI TAP H O A H O C 9

T r o n g q u a t r i n h d a y h o c cV T H C S da c 6 n h i e u e m h o c s i n h h o c 16 n a n g k h i e u
ve k h a n a n g t i i d u y va h o c t a p m o n hcSa hoc. C h a n g h a n , ccS e m t h i c h k h a m p h a t h e

js^nang vtet

1. PhiTdng phap tinh theo cdng thuTc hoa hoc

• Ooi vdi hdp chat c6 hai nguyen to:
TacoCTTQ: A,By

'"^^

o/„m^ = — ^ . 1 0 0 %
y.M„
%m„=^-^.100%
M

^ % m , ^ xJVI,
% m „ y.M„
B y B

m , ^ xjyi^ ' m„ y.M„
B yB

• Doi vcfl hdp chat c6 nhieu nguyen to:
Ta CO (TTTQ: AxByCz
+ each 1: Thiet lap cong thiTc ddn gian nhat ((TTOGN)
x:y:z=^:^:^^CTDGN
M, M 3 M ,

A . L i t h u y e t t r o n g tarn
B. PhUcfng p h a p g i a i b a i t a p

Hay: x:y:z =

C . B a i t a p ap d u n g

A%

:

B% C%
:
M3 M ,
CTPT

(TTOGN

D . HUcVng d a n g i a i

M,
Di/a vao Mhdp chat

E. Bai t a p t U l u y e n ( t i i l u a n va t r i e n g h i e m ) .

+ each 2: Thiet lap cong thuTc phan tCf (CTPT)

H y v o n g vofi k e t cau va n o i d u n g ciia b o sach, p h a n n a o se l a m c h o d o c gia, dac

M,.x

b i e t la cac e m h o c s i n h t i m t h a y nhufng d i e u b 6 i c h va n i e m say m e t r o n g viec h o c

M^.y
mg

M,.Z_MA,B,C, ^ ^ ^ ^ ^
^\B^C^

'

tap h o a h o c .
T r a n trong cam d n !
C a c tac gia

Nhd sach KJtajtg Vietxitt trdn tronggim thieu toi Quy doc gid vd xin lang
nghe moi y kim doug gop, de aion sach ngdy cdng hay horn, bo ich han. Thu
xin giti ve:
Cty T N H H Mot Thanh Vien - Dich V u Van Hoa Khang Viet

Hay: ^ ^ ^ J } o ± ^
A%
B%
0%

'V^^
100

cTPT

'

Vi du 1: Mot hdp chat cua kim loai R vdi oxi (kim loai R chu'a biet hoa tri).
Trong do oxi chiem 3 0 % ve khoi lu'cJng. Xac dinh ten kim loai R?
Hu'dng dan: Ooi vcfi dang nay chijng ta can xay di/ng phu'dng phap giai
cho hoc sinh theo cac bu'dc sau:
+ Oat cong thut tong quat (CTTQ) va suy ra hoa tri cua R
j,;,^ ^\
CFTQ: R 0 „ ^ Hoa tri ciia R : ^^Z

71, D i n h T i e n H o a n g , P. D a k a o , Q u a n 1, T P . H C M
T e l : (08) 39115694 - 39111969 - 39111968 - 39105797 - F a x : (08) 39110880

+ Ap dung cong thCrc:°!^I!1KL=

Hoac Emaih khangvietbookstore@yahoo.com.vn

va hoa tri cua R.

^

(jg' thiet lap bieu thtfc hien he giiJa MR

Bdi dudng hgc sink gidi Hda hgc 9 — Cao Cxi Gidc

M„ = Ll^ do hoa tri cue R la
"
3.x

^. 70.y_
30.x 16

Ta c6:

"

/x

%mg.X

nen

56 2y
3 x

va hoa trj cua R.
63.64.y^M,
36,36.x

+ Cuoi cung ta bien luan hoa trj

de xac djnh ten kim loai R

(Li/u y: kim loai c6 hoa tri tif 1 den 4, phi kim hoa tri tif 1 den 7)

56 2y
=> M , = 2 • X
32

2y/
/ X
MR

MR

4

28

56

84

112

18,7

37,3
Loai

56

74,7

2. Phu'G^ng p h a p bao toan khoi lu'dng

(Fe)

Loai

- Nguyen tac cua phUdng phap. Tong khoi lu-dng cac chat tham gia phar
ling bang tong khoi luWng cac chat tao thanh sau phan uTng.
- Trong mot phan trtig hoa hoc c6 n chat (ke ca chat tham gia va chat tac
thanh), neu biet khoi lu'dng cua (n - 1) chat thi van dung djnh luat bao toar
khoi lu'dng.

Vay nguyen to R la Fe.

+ Dat cong thiTc tong quat (CTTQ) va suy ra hoa trj cua nguyen to con iai
CTTQ: R^Oy ^ Hoa tri cua R :
%m3.x

=—

MB

de thiet lap bieu thirc hien he giiJa M R
.y
K

va hoa tri cua R.

16 2y
3 x

3

4

Hitaing dan:

»/.
"

2

3

Vi dM 2: Mot oxit c6 chu^a 6 0 % oxi ve khoi lydng. Xac djnh cong thCrc Oxit tren.

4?^
=^
60.x 16

1

2

Loai

+ Ap dung cong thCrc:

'\

1

Ket luan: Kim loai c6 hoa tri I I I va M = 56 la Fe

Ta c6:

M 3

M. = ^
3.x

nen

do hoa tri cua R la

Vi du 1: Cho luong khf CO di qua m gam Fe304 sau phan u'ng thu du'dc 24,y
gam chat ran, va 17,6 gam CO2. Tim m?
Hitdng dan: Phan tich dC kien de bai, nhan thay khong the tinh t r u t tief
ngay vi so chat tham gia va chat tao thanh la bon nhuYig chi biet khoi lu'dng
chat. Mat khac chu'a biet khoi lu'dng Fe304 da tham gia phan u'ng het hay cor
du" nen khong tinh theo kieu bai toan can bang mol binh thu'dng.
Do do ta di/a vao phu'dng trinh phan Crng de tim them du' kien cho bai toan
Fe304 + CO —

FeO+ CO

Cuoi cung ta bien luan hoa trj

de xac djnh ten nguyen to R

^ 3Fe0 + CO2
-> Fe + CO2

Qua phu'dng trinh nhan thay:
17,6

2y/
/ x

1

2

3

4

5

6

7

MR

5,3

10,6

16

21,3

26,7

32

37,3

Vay nguyen to R la lull huynh => CTPT Oxit: SO3
V I du 3: Mot hcJp chat gom Kim loai chu-a biet hoa trj vdi luU huynh (biet S c6
hoa tri II), trong do lu'u huynh chiem 36,36% ve khoi luWng. Xac dinh cong
thirc phan tCr hdp chat tren?
Hu-dngdan:

'

^

CTTQ: R^Sy ^ Hoa trj cua R : ^v/

.|

= 0,4mol
44
Khi du du' kien ta ap dung dung djnh luat bao toan khoi lu'dng:
"2

f^Fe^o. =31,1gam
V i d u 2: Cho luong khf CO du' di qua hon hdp X gom cac oxit:

Fe304, AI2O3,

MgO, ZnO, CuO nung nong, sau mot thdi gian thu du'dc ho hdp khf Y ve
23,6 gam chat ran Z. Cho Y Ipi qua binh difng dung djch nu'dc voi trong du",
thay CO 40 gam ket tua xuat hien. Xac dinh khoi lu'dng X.
Hitdng dan: n

CaCOg

40
.| QQ

= 0,4mol

COz + Ca(0H)2 ^ CaCOj i + H2O (1)
0,4

<-

0,4

X + CO, t°: AI2O3, MgO khong bi khu".
CuO + CO —

^

Fe304 + CO —
FeO + CO —

^
^

(2) (3) (4) (5) ^

3FeO + CO2 (3)
Fe + CO2 (4)

n,o

Sddo phan iTng : RCOOH + O2
So mol O:

0,1.2

^ CO2
?

+

H2O

0,3.2

0,2.1

Di/a vao sd do tren ta ap dung nguyen tac BTNT cho nguyen to Oxi.

Cu + CO2 (2)

Ta CO no(RCOOH) + no(02 pu") = no(C02) + no(H20)
no(02 pu')= 0,6mol - > n o ^ = 0 , 3 m o l

> V= 0,3.22,4= 6,72 lit

Vi d u 2: Cho 13,36g hon hdp gom Fe, FeO, FejOa va Fe304 phan iTng het vdi
dung dich HNO3 bang du', thu du'dc 1,344 lit khi NO (san pham duy nhat) d

Zn + CO2 (5)

ZnO + CO

Hi/dng dan: Ta nhan thay khong the viet phu'dng trinh hoa hoc vi chu'a
biet cong thiTc cu the axit ma chi biet cong thiTc chung cua axit RCOOH do do
ta thIet lap sd do phan iTng :
..
, .

=n,o^=0,4mol

(dktc) va dung djch X. Co can dung dich X thu dUdc m gam muoi khan. Tim
gia tri m thu du'dc?

Theo dinh luat bao toan khoi li/dng: mx + mco = MrSnz + nn^^^
=> mx = mz + m(,Q^ - mco = 23,6 + 44.0,4 - 28.0,4 = 30 gam
Vi du 3: Hoa tan het 7,74 gam hon hdp bot Mg, Al bang 500ml dung dich HCI
IM va H2SO4 0,28M thu du-dc dung dich X va 8,7361 lit H2 (dktc). Co can
' ' dung dich X thu du'dc l^dng muoi khan la bao nhieu?
$

HWdngdan:

Hitdng dan: Ta c6: n^,„ = 1^11
^ 0,OSmol ^
22,4
Sd do phan iTng:
Fe, FeO, Fe203 va Fe304 + HNO3
Gpi x la so mol Fe(N03)3

Ap dung dinh luat bao toan nguyen to N, ta c6:
%HN03)

Taco:

n„ = M ^
= 0,39mol
H2
22,4
HHCI

n^,

=> 11,36 + (3x+0,06).63 = 242 + 0,06.30 + (l,5x + 0,03).18
= mmua + m^^

=^mmu6i = 7,74 + 0,5.3,05 + 0,14.0,8 - 0,39.2 = 38,93 gam.
3. Phu'dng phap bao toan nguyen to

Trong mot cac phu'dng trinh hoa hoc, cac nguyen to luon du'dc bao toan
->T6ng so mol cua mot nguyen to A tru'dc phan iTng hoa hoc luon bang tong
so mol cua mot nguyen to A do sau phan lirig.
001 vdi dang bai tap nay cac em khong can viet phu'dng trinh (hdac c6
tru'dng hdp khong the viet phu'dng trinh, hoac phu'dng trinh phtfc tap) ma chi
lap sd do phan (fng giCa chat tham gia va san pham. Sau do thiet lap moi
quan he bao toan cho nguyen to c6 lien quan den du' lieu can tim va giai
Vi du 1: Dot chay hoan toan O,lmol axit Cacboxylic ddn chiTc, can vCra du V lit
02 (dktc) thu du'dc 0,3 mol CO2 va 0,2 mol H2O. Tinh gia tri cua V ?
6

(3X+0,06) mol

Mac khac: m.^ + m^^^^ = m,^,^^^,^ + mNo + m^^^

=0,28.0,5 = 0,14mol

Ap dung OLBTKL: mhh+ mHci + m^^

= "N(Fe(N03)3 + ^NINO) =

Di/a vao sd do ta thay: n^^^ = ^n^^Q_^ = -^(Sx + 0,06) = (1,5x + 0,03)mol

= 0,5.1 =0,5mol

H2SO4

Fe(N03)3 + NO + H2O

=^ X = 0,16 mol => m,^,^o^,^ = 0,16.242 = 38,72 g.
Vi d u 3: Hoa tan hoan toan hon hdp gom 0,14 mol FeS2 va a mol CU2S vao
axit HNO3 vLTa du, thu di/dc dung dich X (chi chu'a 2 muoi sunfat) va khi
duy nhat NO. Tim so mol CU2S da tham gia phan iTng?
Hitdngdan:

Sd do phan iTng:

2Fe2S ^ ^ ^ ^ ^ Fe2(S04)3
0,14mol
CU2S a mol

' •'•
^'^ '

0,7nriol
>

2CuS0'4
2a mol

Ap dung dinh luat bao toan nguyen to S, ta c6:
0,14.2 + a = 0,07.3 + 2a ^ a = 0,07 mol

''^
;

4. Phu'dng phap tang — giam khoi lu'^ng

N2(C03)3

- Nguyen tac cua phu'dng phap: Khi chuyen tCr chat nay sang chat khac thl
khoi lu'cJng tang hay giam mot lu'dngAm( h a y A V d o i vdi chat khi), d o cac chat
khac nhau c 6 khoi lu'dng mol khac nhau (hay doi vdi chat khi: ti le mol khac
nhau). Di/a v a o su" tu'dng quan ti le thuan cua s i / tang - giam, tinh du'dc khoi
lu'dng

(hay the tich) chat tham gia hay tao thanh sau phan (ing.

Bai toan giai du'dc theo phu'dng phap bao toan khoi lu'dng se a p dung du'dc
cho phu'dng phap nay. Nhu'ng vcfi phu'dng phap

khong can biet het (n-1)

TGKL

dai lu'dng ta van giai du'dc neu biet du'dc SLT bien thien A m h a y A V .

6HCI -> 2NCI3

(2N+180)g

+

3CO2 + 3H2O (2)

(2N+213)g

3mol

T u ' ( l ) va (2), ta thay:
CiTtao ra 1 mol CO2 thi khoi lu'dng muoi sau phan Cmg tang l l g .
Vay de tao ra 0,03mol CO2 thi khoi lu'dng muoi sau tang 0,33g.
Vay khoi lu'dng muoi sau phan Cfng = 10 + 0,33 = 10,33g.
V i d u 2: N h u n g

mot thanh

sat nang

50g vao 400ml

la 51gam.
a) Tinh khoi lu'dng dong tao thanh bam tren thanh sat

Phu'dng trinh : C a C O j +

b) Tinh CM cac chat trong dung dich sau phan Cmg

2HCI

CaCb + C O 2 + H 2 O

Ve khoi lu'dng lOOgam

lllgam

Neu X mol CaCOs phan iTng thi sau phan uCng : A m = agam
, dt/a v a o ti le nay khi biet a ta xac djnh du'dc x va ngu'dc lai.

Nang cao hdn muoi kirn loai chu'a biet hoa t n II hay hon hdp muoi kirn loai
chu'a b i e t :
Phu'dng trinh : MCO3 +
Nhan thay

CLT

2HCI

MCI2 +

Ve khoi lu'dng M + 6 0 g a m

->

MCI2

Cur I m o l MCO3 phan iTng thi sau phan uTig : A m = ( 7 1 - 6 0 ) g a m

X=

71-60

b gam

Doi vdi nhuTig loai bai tap khong c 6 it so lieu ma phu'dng trinh phdc tap c 6
the giai hoac khong giai du'dc thong qua he phu'dng trinh. Nhung ta thay c6 s i / bien
thien ve A m h a y A V thi c6 the ap dung theo phu'dng phap tang giam khoi lu'dng.
V I d u 1: C h o l O g h o n h d p 2 m u o i c a c b o n a t k i m loai h o a t r i II v a I I I
t a c dung vdi axit HCI vu^ d u , thu du'dc dung djch A v a 672ml khi (dktc).
CO can dung djch A thu du'dc bao nhieu g a m muoi?

MCO3

+

2HCI

Cu

' '

Imol

Vay X mol sat phan uTng se tao ra x mol dong tang 5 1 - 50 =1 g .
X = ^ = 0,125mol -» npe = ncu = n^^so, = ^^^3^^ = 0,125mol
= 0,3125mol

^ CM CUSO4 c o n lai = 0,5 - 0,3125 = 0,1875M.
V i du 3: Khi lay 14,25g muoi clorua ciia mot khi loai X chi c6 hoa trj II v a mot
la 7,95g. Hay tim cong thuTc cua hai muoi.
Hifdng

dan: T a c 6 cong thCrc cua hai muoi la: XCI2 ( M = X + 71) va

X(N03)2 (M = X + 124).

Ta thay CLT I m o l muoi nitrat cua M c6 khoi lu'dng Idn hdn 1 mol muoi clorua
la: (X + 124) - (X + 71) = 53g.
T h e o gia thiet khoi lu'dng khac nhau la 7,95g. Vi goc N O " c 6 khoi lu'dng Idn
hdn goc CI" nen tCr gia thiet ta c6:
mX(N03)2 - mXCl2 = 7,95g.

MCO3

ddA

N2(C03)3

672mlkhi

r i g muoi

Cac phu'dng trinh hoa hoc:
(M+60)g

+

Imol

lu'dng muoi nitrat cua X vdi so mol nhu" nhau, thi thay khoi lu'dng khac nhau

, difa v a o ti le nay khi biet b ta xac dinh du'dc x va ngu'dc lai

Hi/dng dan: l O g a m hon hdp \

FeS04

Imol

Nong d p M cua dung dich CUSO4 da phan tTng la: 0,3125M

M + 7 1 gam

Neu X mol MCO3 phan (fng thi sau phan Crng : Am =

CUSO4

Nong d o M cua dung dich FeS04 la: C „ = =

CO2 + H2O

I m o l MCO3 tham gia thi tao ra I m o l muoi

+

Imol

CLT I m o l sat (56g sat) phan ung se tao ra 1 mol dong (64g dong) tang 8g.

a1
=> X =

dich

Hitdng dan: Phu'dng trinh hoa hoc
Fe

GUI' I m o l CaCOa phan uYig thi sau phan ling : A m = 1 1 1 - 1 0 0 = l l g a m

dung

C u ' s 0 4 0,5M, sau phan uTig lay thanh sat ra lam kho can lai thi khoi lu'dng

VI d u : Khi day ve tinh chat hoa hoc cua axit tac dung vdi muoi :
Nhan thay cu" I m o l CaCOs tham gia thi tao ra I m o l muoi CaCb

Hoi

+

7 95

Vay so mol muoi cua kim loai X la: n = - r — . 1 = 0,15mol

.

Do

=> Khoi lu'dng mol cua muoi clorua cua X la:
->

MCI2

+

(M+71)g

CO2

Imol

+

H
H 2 0 (1)

M =^-^^= 9 5
0,15

X + 71 = 9 5

X = 2 4 -> X la M g .
9

5. Phu'dng phap dung khoi lu'dng mol trung binh ( M )
Nguyen tac cua phu'dng phap: M la khoi lu'dng cue 1 mol hon hdp.
M

n.|M, + n^Mj + njMg + ...

=

Va rdi vao be tac khong giai du'dc.
Vi 2 kim loai cung nhom I nen cung hoa tri nen:

f V2M2 + V3M3 + ...

Oat ky hieu chung ciia 2 kim loai la R.

v..

Phu'dng trinh phan iCng : 2 R + 2 H2O

Hoac : M = XiM] + X2M2 + X3M3 + ...
Vdi Ml, M2,

M3...:

Xi, X2, X3...: so phan mol ciia cac chat trong 1 mol hon hdp.

,

0,1 mol

Gri'

Do 2kim loai cung nhom I va thuoc 2 chu ky lien tiep nhau nen ta c6
MNa = 23 < 27 < MK = 39.

-_3M,+(V-V,)M,

n

;\

0,2

Khi hdn hdp g S m 2 chat: Mi < M < M2.
+(n-n^)Mg

2 ROH + H2 T

0,2 mol

khoi lu'dng mdl va ni, n2, n3...la so mol cac chat trong hon hdp.

Vi, V2, V3...; the ti'ch cac khi trong hon hdp khi.

-n^M^

X + y = n,,, ^ - 0,1

- each giai theo trung binh:

n, + n^ + ng + ...

M hhkhi

Ax + B y = 5,4

Sau d o lap he

Vay hai kim loai d o la Na, K.

V

Vi du 2 : Hon hdp X g o m hai muoi cacbonat cua hai kim loai nhom IIA thupc 2
chu ky ke tiep nhau trong bang tuan hoan. Hda tan 3,6 gam hon hdp X

M = XiMi + (1 -X2)M2.

bang dung dich HNO3 du, thu du'dc khi Y. Cho toan bp lu'dng khi Y hap thu

Co the ti'nh di/a vao M theo s d d d cheo:
Ml

^

M - M2

ni, Vi, Xi.

het bdi dung dich Ba(0H)2 du' thu di/dc 7,88 g a m ket tua. Hay xac dinh
cong thiTc cua hai muoi va tinh thanh phan % ve khoi lu'dng mSi muoi trong X.
HWdngdan:

Ml -

M - n2, V2, X2.

'

Oat C r Chung cua 2 muoi cacbonat ciia hai kim loai hoa tri II la RCO3
PTTHH : RCO3 + 2HNO3

Phu'dng phap nay t h a d n g ap dung giai bai toan hon hdp hai hay nhieu chat

R(N03)2 + H^O + CO^T

CO2 + Ba(OH)2 -> B a C O g + Hp

CO cung mpt ti'nh chat tu'dng du'dng nad d d . Sai lam nhat khi giai bai tap nay
hdc sinh thu'dng du'a v'e dang bai toan hdn hdp. Nhu'ng khi tien hanh giai

'^BaCOg

thu'dng rdi vao be tac la an so nhieu hdn so phu'dng trinh nen khong tim du'dc

'^'BaCOg

7,88
197

- 0.04mol ^ n,co^= n^^=

0,04mol

triet de cac an sd. Dan den mat thdi gian va chan nan trdng qua trinh giai bai
tap hda hoc.
VI d u 1 : Hoa tan 5,4g hon hdp 2 kim b a i cung nhdm I 6 2 chu ky lien tiep
nhau vad nu'dc thu du'dc thu du'dc 2,24 lit khi (dktc). Xac dinh ten 2 kim b a i .
Hitdng

dan:

Dat an so cho ten va s5 mol cho kim b a i can tim

2 B + 2 H2O
y

10

2 BOH + H2 T
y

3 '

3,6

^ = ^ — = 9 0 ^ M R = 30
nRC03
"RCO3

0,04
0,04

Vi 2 kim b a i hpa tri II lai thupc 2 chu ky ke tiep nhau trpng bang tuan hpan:
Ml < M < M2 r:> Ml < MR = 3 0 < M2

- Hdc sinh thu'dng sai lam nhu' sau:
2 A + 2 H 2 0 - > 2 A O H + H2T

MRCC, =

^'^'^^

Vay 2 kim b a i dp la Mg va Ca

* ''

CTHH cua 2 mupi: MgCOa va CaC03
Gpi a, b Tan lu'dt la so mol cua MgCOs va CaC03
, 184a + 100b = 3,6
Ta co:
'
a + b = 0,04

<
^

a = 0,025 mol

':s

)

* '
.

^

b - 0 , 0 1 5 mol
11

o/
'

M9CO3

= !!Wo^ . 1 ooo/o rn^^

3,6

. 1 ooo/o = 58.33%

= 100% - 58,33% = 41,67%

=^ % " i c 3 C 0 3

Ta CO he phu'dng trinh:

^

[ 95x + 133,5y + 127z = 53,0

Vi dv 3: Hoa tan vao niTdc 7,14g hon hdp muoi cacbonat trung hoa va
cacbonat axit cua mot kim loai hoa tri I, roi do them lu'dng dung dich HCI
vLTa du thi thu du'dc 0,672 I khi d dktc. Xac dinh ten kim loai tao muoi.
Ht/dng dan: Oat kf hieu kim loai la M, x, y Ian lu'dt la so mol cua M2CO3 va
MHCO3. Ta CO phu'dng trinh phan Cfng :
M2CO3 + 2 HCI

2 MCI + H2O + CO2 T

X

X

MHCO3 + HCI ^ MCI + H2O + CO2 t

y

y
muoi = X + y =

M muoi = —

0,03

o

89

<

=

= 238. Vi M + 6 1 <

M

< 177

r:>

0,03

(mol)

a

M la Cs.

X

y

i,5y

Fe + 2 HCI -> FeCb + H2t
z
».
z
z

0,5a

'

b

0,75b

(1)

a
0,5b

!'

2Zn + O2

2ZnO

c

c

0,5c

2 Cu + O2
d
0,5d

(3)

2 CuO
d

B gom (MgO, AI2O3, ZnO,

MgO + 2HCI
a
2a

(4)

CuO)

MgCl2 + H2O

(5)

AI2O3 + 6HCI ->2AICl3 + 3 H2O (6)
0,5b
3b
ZnO + 2Ha -^ZnCl2 + H2O
c
2c

(7)

CuO + 2HCICUCI2 + H2O

(8)

d

. '

2d

'

,,

Ap dung dinh luat bao toan khoi lu'dng ta c6: mp + m^^ = m,'Q
=> "^02 =

12

,

4 A I + 3 O 2 — ^ 2 A l 2 0 3 (2)

x
' 2 Al + 6 H C I 2 AICI3 + 3H2T

y

Vdi 3 an, c6 2 phu'dng trinh.
Tim khoi lu'dng 3 kim loai tiTc la tong :
24x + 27y + 56z. .
Tach (2) ta du'dc: 24x + 27y + 56z + 71(x + l,5y + z) = 53.
24x + 27y + 56z = 53,0 - 0,5 x 71 = 17,5 (g).
Vi du 2: Cho 3,8 gam hon hdp A gom cac kim loai : Mg, Al, Zn, Cu tac dung
hoan toan vcfi oxi du' thu du'dc hSn hdp chat ran B c6 khoi lu'dng la
5,24gam. Tinh the tich dung djch HCI IM can dung (toi thieu) de hoa tan
hoan toan B.
HWdng dan:

2Mg + O2 ^ ^ 2 MgO

M muon = 238 < 2M + 60

Mg + 2 HCI ^ MgCl2 + H2r
X

(2)

Goi a, b, c, d Ian lu'dt la so mol cua Mg, Al, Zn, Cu c6 trong hon hdp A.

6. Phu'dng phap ghep an so
(
Nguyen tac cua phu'dng phap: Dung thu thuat toan hoc ghep an so de giai
cac bai toan c6 an so Idn hdn so phu'dng trinh toan hoc lap du'dc ma yeu cau
bai ra khong can giai chi tiet, day du cac an.
Dang nay thu'cJng gap khi tinh toan khoi lu'dng chung cua hon hdp cac chat
(hon hdp kim bai, hon hdp muoi, ...) tru'dc hoac sau phan (inq ma khong can
tinh chi'nh xac khoi lu'dng tiTng chat trong hon hdp.
Vi du 1: Chd hon hdp X gom Al, Fe, Mg tac dung v6i dung dich HCI du" thu
dutJc 11,2 lit khi (dktc) va 53,0g muoi. Tim khoi luWng hon hdp X.
Hitdng dan: Gpi x, y, z Ian lutrt: la so mol cua Mg, Al, Fe c6 trong hon hdp )Q
PTHH:
t,

(1)

each 1: Dung phu'dng phap ghep an so

0 672
nco2 =

x + —y + z = 0,5

- mp = 5,24 - 3,8 = l,44g

,. i

13

w

1 44
Theo (1,2,3,4) :

- 0,5a + 0,75b + 0,5c + 0,5d = ^

- T h e o PTHH: n^^^^^ = n^^^ = 0,75 mol => m^^p^g = 0 , 7 5 . 1 0 0 = 75 g
= 0,045mol

- Nhu' vay con 5 g a m CaCOs khong bi phan huy. Do d o chat ran tao ra
n o m : CaCOj d i / , AI2O3, Fe203 va CaO.

Theo (5,6,7,8) : n^^,, = 2a + 3b + 2c + 2d = An^^ = 4 x 0,045 = 0,18nnol
=> \ ^ r , - - ^ = —

= 0,181 = 180mI

f v . . .

Cach 2: Sau khi t i m ra so mol O2.

' '

Nhan xet: Trong cac cap chat phan (fng la : 1 va 5 ; 2 va 6 ; 3 va 7 ; 4 va 8
thay so mol axit luon gap 4 Ian so mol O2.

%ALO, =

15,22%

.100%
67

'

% F e , 0 3 -- — . 1 0 0 % = 1 4 , 6 2 %
67
%CaC03 - ; ^ . 1 0 0 %
67

Do d o : So mol HCI = 4 x 0,045 = 0,18 mol.

;

7,4%

%CaO = 62,76%

Tim ra the ti'ch dung dich la 180ml.

Vi du 2: Cho m g a m hon hpp Na va Fe tac dung het vdi axit HCI. Dung djch

7. PhUdng phap tu" chon lu'dng chat
Nguyen tac cua phu'dng phap: Phan tram lydng chat trong dung dich hoac

thu du'dc cho tac dung vdi Ba(0H)2 du' roi Idc lay ket tua tach ra, nung

trong hon hop nhat dinh la mot dai lu'dng khong d o i . Khi giai ngu'di giai tu'

trong khdng khi den lu'dng khong doi thu du'dc m g a m chat ran. Ti'nh %

chon lu'dng thi'ch hdp de giai bai toan
2.2.7.2.

Xay di/ng

va sir dung bai tap hoa hoc theo phWdng phap giai bai

lu'dng moi kim loai ban d a u .
Hi/dng

dan:

- PTHH xay ra khi cho m gam hon hdp Na va Fe tac dung vdi HCI:

tap til chon iWdng chat trong day hoc d trWdng THCS

2Na + 2HCI -> 2NaCI + H2

(1)

de bai chi cho lu'dng chat du'di dang tong quat hoac khong noi den lu'dng chat

Fe + 2HCI -> FeCb + H2

(2)

nhu'ng biet du'dc ti le giiJa cac chat

- PTHH xay ra khi cho dung dich t h u du'dc tac dung v6i Ba(0H)2 diT:

Cac e m thu'dng lung tung va khong xac dinh hu'dng giai khi gap dang nay vi

Khi gap dang nay cac e m c6 the chpn lu'dng chat c6 m o t gia tri nhat dinh
de tien viec giai. Co the chpn lu'dng chat la mpt mdl hay m p t so mol theo he so
ty lu'dng trong phu'dng trinh phan iTng; hoac lu'dng chat la lOOg,...
Vi du 1: Hon hdp g o m CaCOs Ian AI2O3 va Fe203 trong d o AI2O3 chiem 1 0 , 2 % ,
Fe203 chiem 9 , 8 % . Nung hon hdp nay 6 nhiet d p cad t h u du'dc chat ran c6
lu'dng bang 6 7 % lu'dng hon hdp ban dau. Ti'nh % lu'dng chat ran tao ra.
Hitdng

dan:

FeCl2 + Ba(0H)2 -> Fe(0H)21 + BaCl2(3)
- PTHH xay ra khi nung ket tua trong khong khi:
4Fe(OH)2 + O2

- Gpi m = mpe + mNa = 100 gam
=^"^Fe203

- Gpi khoi lu'dng hon hdp ban dau la 100 g t h i : m^, ^

2 3

= 10,2g

- - ^ 2Fe203 + 4H2O ( 4 )

-100gam=^n,^^o^

- T h e o P T H H ( 4 ) : n,^,„,,^ = 2.n,^^„^
- Theo PTHH ( 3 ) : n , ^ „ ^

m^co. - 8 0 g

- PTHH xay ra khi nung hon hdp: CaC03

_o,625mol
2.0,625 = 1,25 m o l

— > CaO + CO2T

hon hdp ban dau. Nhu vay d p giam khoi la do CO2 sinh ra bay d i .
33
- V a y m^Q^ = 1 0 0 - 6 7 = 3 3 g => n^^^ = — = 0 , 7 5 m o l

_
;

'

n,^^„,,^ = 1,25 m o l

- T h e o PTHH ( 2 ) : n^^ := n^^j,,^ = 1,25 m o l

- Thed bai ra, lu'dng chat ran thu du'dc sau khi nung chi bang 6 7 % lu'dng

14

1^

m^^ = 1,25.56 = 7 0 g a m

-Vay:%Fe = 70%
% Na = 3 0 % .
Vi d u 3:

Hon hdp g d m NaCI, KCI (hon hdp A) tan trong nu'6c thanh dung

dich. Them AgN03 du" vao dung dich nay thay tach ra m p t lu'dng ket tua
bang 2 2 9 , 6 % so vdi A. Tim % moi chat trong A.

\5

Hitdng dan:
- PTHH xay ra:
NaCI + AgNOa - > AgCI + NaNOa
KCI + AgN03 - > AgCI + KNO3

Do chu'a biet X la kim loai hay phi kirn nen ta bien luan hoa trj x tCri den 7
2
3
4
5
1
6
7
X
24
32
16
40
8
48
56
Mx

(1)
(2)

'

, : -nr

229 6
- Gpi rriA - lOOg

m^g^, = 229,6gam

n^g^i = 1 ^ = ^'^

- G o i PNaCI = X

So mol AgCI sinh ra d phan uTng (1) la: x
So mol AgCI sinh ra d phan iTng (2) la: 1,6 - x
=>n^ci='"'6-x
-Ta

c6: MNaci-nNaci + MKCI-DKCI = 100

=> 58,5x + 74,5(1,6 - x) =
Vay: nNaci = 1,2 mol

/O =i> x = 1,2.

^ |%KCI = 100% - 7 2 % = 29,8%

8. Phi/dng phap bien luan de tim cong thu'c phan tuT
Nguyen tac: Khi tim cong thu'c phan tCr hoac xac dinh ten nguyen to thu'dng
phai xac dinh chinh xac khoi lu'dng mol, nhu'ng nhiJng tru'dng hdp M chu'a c6
gia tri chfnh xac doi hoi phai bien luan.
Pham vi uYig dung: Bien luan theo hoa tri, theo lu'dng chat, theo gidi han,
theo phu'dng trinh v6 dinh hoac theo ket qua bai toan, theo kha nang phan uTng.
Khi giai dang nay cac em thu'dng lung tung va giai den g\\jta chi/ng thi diTng
lai vi luc do so an nhieu hdn so phu'dng trinh ma khong the ap dung cac
phu'dng phap khac nhu' ghep an so, hay phu'dng phap bao toan khoi lu'dng.
Luc nay cac em can tim each bien luan thfch hdp. Gia s(f mot phu'dng trinh c6
hai an so la khoi lu'dng mol (M) va hoa tri cua nguyen to. Ta c6 the bien luan
hoa tri cua nguyen to theo khoi lu'dng mol
VI du 1: Dot chay I g ddn chat X can dung lu'dng vCfa du 0,7 (I) O2 (dktc). Xac
dinh X?
Ht/dng dan: Goi x la hoa trj ciia X
+

|02 ^

0,7

0,7

5,6x

22,4
1

M , = ^ = 8x
6,5x
16

vi du 2: Cho 3,06g oxit MxOy tac dung het vdi dung djch HNO3, khi c6 can
dung dich thay tao ra 5,22g muoi khan. Xac dinh kim loai M biet no chi c6
mot gia tri duy nhat.
HWdfngdan: MxOy

+

2yHN03 ^

xM(N03)2y + yHzO

Bao toan nguyen to H: n „ „ = a ^ n^^^o, = 2a

,r

Bao toan khoi lu'dng: 3,06 + 63.2a = 5,22 + 18a

''

a = 0,02 mol - > n^^o, = 0^04 mol

m^^^,, = 1,2.58,5 = 70,2gam

J%NaCI-70,2%

2X

—>

X2OX

n,HNO,

Bao toan nguyen to N: nMuoi = — ^
x
Mmuoi =

5,22

n

(n: hoa tri M)

.n = 130,5n ^ M = 130,5n - 62n = 68,5n

'HNOQ

Bien luan M theo hoa tri n ta c6: •
n

1

2

3

4

M

68,5

137

205,5

274

Vay kim loai M la Ba.
Vi dy 3 : Hoa tan 4,0g hon hdp gom Fe va mot kim loai hoa trj I I vao dung
dich HCI thi thu du'dc 2,24 lit H2 (dktc). Neu chi dung 2,4g kim loai hoa tri I I
cho vao dung dich HCI thi dung khong het 500ml dung djch HCI I M . Xac
dinh kim loai hoa tri II?
Hitdng dan: n^^ = n^^ = 0,1 mol

A = -1^40^M<40
0,1

nHci = 0,5 mol
M +

2HCI

0,25

< - 0,5

=

MCI2

+ H2

2.4
- = 0 , 2 5 - > M > 9,6
M
9,6 < M < 40 - > M la Mg.

T H i ; VIEW T/MH 3i"Ni; THIjAfTj
17

Chimnql:

C A C LOAI HOP CHAT V O C O
A. U T H U ^ K T Tl^pNG TArr

I. OXIT
.A ^ 1 •
1. Phan loai oxit
Di/a vao tinh chat hoa hoc, oxft di/dc chia lam bon loai:
1.1. Oxit baza
- La oxit tac dung vdi dung dich axit tao thanh muoi va nu'dc, la oxit c6
bazd tu'dng tTng.
- Thu'dng cac oxit bazd la oxit cua kim loai vdi oxi (tru" Mn207...)
Vidu: MgO, K2O, AgzO . .
1.2. Oxit axit
- La oxit tac dung vdi dung djch bazd tao thanh muoi va nu'dc, la oxit c6
axit tu'dng uTng

- Thu'dng cac oxit axit la oxit cua phi kim vdi oxi (trCC N2O..)
Vi du: SO2, C I 2 O 7 , C O 2 . .

- Mot so oxit axit con du'dc goi la anhidrit axit [nghfa la oxit axit tao ra llam mat nWdc axit ti/cfng utig)
I

Vi du: SO2, P2O5, C O 2 . .

1.3. OxitlWdng tin/i
La oxit tac dung du'dc vdi dung djch axit va dung djch bazd tao thanh muoi
va nu'dc.
Vidu: ZnO, AlzOj.SnO, BeO. .
1.4. Oxit trung tinit
La oxit khong tac dung vdi axit, bazd, nUdc con gpi la oxit khong tao muoi.
Vidu: NO, CO, . .
2. Tinh chat hoa hpc cua oxit
2.1. Tinti ctiat lioa iigc ciia oxit Itazcf
a) Tac dung vdi nWdc
I^Qt so oxit bazd + H2O -> dung djch bazd (Ar/e/n)
VI du:

CaO (r) + H20(i)

Ca(0H)2(dd)

b) Tac dung vdi dung dich axit
Oxit bazd + axit -> muoi + nUdc
Vfdu:
CuO(r) + 2HCI(dd)
^ CuClz (dd) + HzOd)
c) Tac dung vdi oxit axit
Mpt so oxit bazd + oxit axit -> muoi
VMu:
CaO(r) + C02(k)
CaCOsw

2.2. Tinfi ctiat hoa hoc ciia oxit axit
a) Tac dung vdi nude
Nhieu oxit axit + nUdc-> dung djch axit
Vidu: P205(r)+ 3H20(,) ^ 2H3P04(dd)
b) Tac dung vdi bazd
Oxit axit + dung djch bazd -> muoi + nu'dc
Vidu:
C02(k) + Ca(0H)2(dd) -> CaCOsM + H20(i)
c) Tac dung vdi oxit bazd
M9t so oxit axit + oxit bazd -> muoi
Vidu: S02(k) + BaO(r) ^ BaSOaco
3. Mot so oxit quan trong
3.1. Canxi oxit (CaO)
- Ten thong thu'dng gpi: Vol song
- Cong thCrc phan tu': CaO
-PhantLrkhoi:
56dvC
- Thupc loai oxit:
Oxit bazd
- La chat ran mau trang, nong chay d nhiet dp cao.
Tinh chat hoa hpc
a) Tac dung vdi nude

,

CaO tac dung vdi nu-dc tao ra chat ran mau trang ft tan trong nu'dc la Ca(0H)2

Vidu: CaO(r) + H20(i) -> Ca(0H)2(dd) + tda nhiet
{phanungtoivdi)
CaO CO tinh hut am, vi the no du'dc dung lam kho nhieu chat.
b) Tac dung vdi axit
Vi du: CaO(r) + 2HCI(dd) -> CaCbfdd) + HzOo
''•..•^
CaO dung de khiT chua dat trong trong trpt.
c) Tac dung vdi oxit axit
Vi du: Oe vol song trong khong khi lau ngay thi bj von lai
•.
C02(k) + CaO(r) ->CaC03(r)

Ung dung
Dung trong cong nghiep Iuyen kim, lam nguyen lieu cho cong nghiep hoa
hoc, khCr chua dat trong trpt, xCr ly nu'dc thai cong nghiep, sat trung, diet nam,
khCr dpc moi tru'dng. .
San xuat canxi oxit
'' '
3) Nguyen lieu
•'
"
Da voi, than da,cui, dau, khi...
'jt, •
b) Cac phan ung hoa hoc
Nung vol bang 16 thu cong hay 16 cong nghiep deu c6 2 phan LCng xay ra:

2. Phan Idal

- Than chay tao khi CO2, phan iTng toa nhiet
C(r) + O2 (k)

- Can CLT vao dp manh cua axit, ngu'di ta c6 the chia axit thanh hai loai:

C02(k)

+ Axit manh: HCI, HNO3, H2SO4...

- Nhiet sinh ra phan huy da voi tao ra voi song
'" )

CaC03(r)

CaO(r) + C02(k)

^'^ *

3.2. LiTu huynh dioxit (SO2)
- Ten thirdng goi:

. \

- Can CLT vao phan iTng vdi kim loai, c6 the chia axit thanh hai loai:

' *

+ Axit thu'dng: giai phong khi H2 nhu" HCI, H2SO4 b a n g

Khi sunfurd, anhidrit sunfuric

^> - Cong thiCc phan tu": SO2
-

Phan tLf I
+ Axit dac biet: khong giai phong khi H2 nhu" HNO3, H2SO4 dac.
- Can c(f vao thanh phan nguyen to trong hdp chat, c6 the phan thanh hai loai:

64 dvC

+ Axit khong chiTa oxi: HCI, HBr, H2S, ...

- La chat khi khong mau, mui hac, doc, nang hcJn khong khi.

+ Axit CO chura oxi: HNO3, H2SO4, H3PO4, ...

Tinh chat hoa hoc

Axit

Ten axit

Goc axit

Ten goc axit

a) Tac dung vdi nifdc

HCI

Axit clohidric

-CI

clorua

Vi d u : S02(k) + H20(i) - > HjSOjcdd)

HBr

Axit bromhidric

-Br

bromua

b) Tac dung vdi dung dichi bazd

H2S

Axit sunfuhidric

=S

sunfua

S02(k) + Ca(0H)2(dd) -> CaS03i(r) + H20(i)

Vi d u :

muoi canxi sufit
c) Tac dung vdi oxit

bazd

S02{k) + CaO(r) ^

Vidu:

CaS03(r)

LTng dung: Dung de san xuat H2SO4, tay trang bpt go trong cong nghiep
giay, diet nam moc.
Dieu Che
tlii'ngliiem

sinh ra bang each day khong khi.
Na2S03(r) + 2HCI(dd)

^

-NO3

nitrat

=C03

cacbonat

H2SO4

Axit sunfuric

= S04

sunfat

H2SO3

Axit sunfurd

= S03

sunfit

H2Si03

Axit silicic

=Si03

silicat

H3PO4

Axit photphoric

= P04

photphat

+ H20(i) + S02(k)

Axit +

Cacfi 1: Dot lu'u huynh trong khong khf

Vi d u :

S(r) + 02(k) - > S02(k)

I I . AXIT

=>
2Fe203(r)

+ 8S02(k)
^

1. 0|nh nghTa
Axit la hdp chat ma phan tu" gom nguyen tu" hidro lien ket vdi goc axit.
Vi d u : HCI, H2SO4, ...

-> C U S O 4 +

H2O

•

b a z d - > muoi +

j

nu'dc

3 H 2 S O 4 -I- 2Fe(OH)3 - > Fe2(S04)3 + 6 H 2 O

HNO3 + NaOH ^ NaN03 + H2O

C^cb 2: Dot quang Pirit sat:
1102(k)

H 2 S O 4 + CuO

muoi + xwidc

3.3. Tac dung vdi bazd

ngiiiep

4FeS2(r) +

quy tim (do)

bazd

Axit + oxit bazd
VI d u :

CuS04(dd) + S02(k) + 2H20(|)

CU(r) + 2H2S04(d) ^

Axit + quy tim (xanh)
3.2. Tac dung vdi oxit

2NaCI(dd)

Cach 2: Dun nong H2SO4 d vdi Cu
b) Trong cong

Axit nitric
Axit cacbonic

3.1. Tac dung vdi cbi thi mau

Cacti 1: Cho muoi Sunfit tac dung v6i axit {nliW: HO,H2S0^ sau do...