Cấu tạo Muối Amoni như thế nào là phù hợp

7/26/2019 Cu to Mui Amoni nh th no l ph hp

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Bin son v ging dy ti USCHOOL.VN : Thy Nguyn Minh Tun THPT chuyn Hng Vng Ph Th T : 01689186513

Trn bc ng thnh cng khng c du chn ca kli bing 1

BIN LUN TM CNG THC CA MUI AMONI

1. Khi nim vmui amoniMui amoni l mui ca amoniac hoc amin viaxit v c hoc axit hu c. V d:

+ Mui amoni ca axit v c : CH3NH3NO3,C6H5NH3Cl, CH3NH3HCO3, (CH3NH3)2CO3,CH3NH3HSO4, (CH3NH3)2SO4, (NH4)2CO3,...

+ Mui amoni ca axit hu c : HCOOH3NCH3,CH3COOH3NCH3, CH3COONH4, HCOONH4,

CH3COOH3NC2H5, CH2=CHCOOH3NCH3,

H4NCOOCOONH4,...

2. Tnh cht ca mui amoniMui amoni tc dng vi dung dch kim gii

phng NH3hoc amin.

Mui amoni ca axit cacbonic tc dng vi axitHCl gii phng kh CO2.

3. Bin lun tm cng thc ca mui amoniV d1: Cho axit cacboxylic X phn ng vicht Y, thu c mt mui c cng thc phn tC3H9O2N (sn phm duy nht). Scp cht X vY tha mn iu kin trn l

A.3. B.2. C.4. D.1.(thi tuyn sinh i hc khi B nm 2012)Hng dn :

Axit cacboxylic X phn ng vi cht Y to ramui c cng thc l C3H9O2N, chng t Y lamin hoc NH3. C 4 mui amoni ng vi cngthc C3H9O2N l :

HCOOH3NC2H5 HCOOH2N(CH3)2

CH3COOH3NCH3 C2H5COONH4

Suy ra c 4 cp cht X, Y tha mn l :HCOOH v C2H5NH2 HCOOH v (CH3)2NH

CH3COOH vCH3NH2

C2H5COOH v NH3

V d2:ng vi cng thc phn t C2H7O2N(X) c bao nhiu cht va phn ng c vidung dch NaOH va phn ng c vi dungdch HCl ?

A.2. B.3. C.1. D.4.(thi tuyn sinh Cao ng nm 2010)

Hng dn :

Hp cht X cha N, va phn ng c vidung dch NaOH va phn ng c vi dungdch HCl nn X c th l amino axit, este caamino axit, peptit hoc mui amoni.

Phn tpeptit c t nht 2 gc - amino axit, 1nhm peptit CONH v c u N (nhm

NH2), u C (nhm COOH) nn s nguyn tO t nht phi l 3, snguyn tN t nht phi l2, snguyn tC t nht phi l 4. Vy X khngthl peptit.

Amino axit c 2 nguyn tC l glyxin c cngthc l H2NCH2COOH, c 5 nguyn tH. VyX khng thl amino axit.

X cng khng thl este ca amino axit (v esteca amino axit phi c t3 nguyn tC trln).

Vy X l mui amoni. X cha 1 nguyn t Nnn X c mt gc amoni, gc axit trong X cha2 nguyn tO nn c dng RCOO. Suy ra X lHCOOH3NCH3 (metylamoni fomat) hocCH3COONH4(amoni axetat).

Phng trnh phn ng minh ha :3 3 3 2 2

3 3 3 3

HCOOH NCH NaOH HCOONa CH NH H O

H COOH N CH H Cl H COOH CH N H Cl

+ + +

+ +

3 4 3 3 2

3 4 3 4

CH COONH NaOH CH COON a NH H O

CH COON H H Cl CH COOH N H Cl

+ + +

+ +

V d3:Cho cht hu c X c cng thc phntC2H8O3N2tc dng vi dung dch NaOH, thuc cht hu c n chc Y v cc cht v c.Khi lng phn t(theo vC) ca Y l :

A.85. B.68. C.45. D.46.(thi tuyn sinh i hc khi B nm 2008)Hng dn :

C2H8N2O3(X) tc dng vi dung dch NaOH thuc cht hu c Y n chc, chng t X lmui amoni to bi NH3 hoc amin n chc.

Nh vy, gc axit trong X c 1 nguyn tN v 3

nguyn t O, l gc3

NO . Suy ra X l

C2H5NH3NO3 (etylamoni nitrat) hoc(CH3)2NH2NO3 (imetylamoni nitrat); Y l


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Trn bc ng thnh cng khng c du chn ca kli bing2

C2H5NH2 (etyl amin) hoc (CH3)2NH2 (imetylamin), c khi lng phn tl 45 vC. Phngtrnh phn ng :

2 5 3 3 2 5 2 3 2

3 2 2 3 3 2 3 2

C H NH NO NaOH C H NH NaNO H O

(CH ) NH NO NaOH (CH ) NH NaNO H O

+ + +

+ + +V d4:X c cng thc C4H14O3N2. Khi cho Xtc dng vi dung dch NaOH th thu c hnhp Y gm 2 kh iu kin thng v u ckh nng lm xanh qu tm m. S cng thccu to ph hp ca X l :

A. 5. B. 3. C. 4. D. 2.(thi thi hc ln 2 THPT chuyn

Nguyn Hu H Ni, nm hc 2011 2012)

Hng dn :X tc dng vi dung dch NaOH, thu c hnhp kh u c kh nng l xanh giy qu tmm. Chng t: X l mui amoni; hai kh l NH3v amin hoc l 2 amin. Amin thkh nn snguyn tC trong phn tbng 1 hoc 2, nu c3 nguyn tC th phi l amin bc 3.V hai nguyn tN nm trong hai ion amoninn gc axit trong X khng th cha N. Mtkhc, gc axit c 3 nguyn t O, suy ra X l

mui amoni ca axit cacbonic, cha gc 23

CO

lin kt vi hai gc amoni.Scng thc cu to ca X tha mn l 3 :

O

O

O

H4N

NH

CH3

CH3

CH3

C

O

O

C O

H3N

NH2

CH3

CH3

CH3

O

O

C O

H3N

NH2

CH2

CH3

CH3

V d5:Cho hn hp X gm hai cht hu c ccng cng thc phn tC2H7NO2 tc dng va vi dung dch NaOH un nng, thu cdung dch Y v 4,48 lt hn hp Z (ktc) gm

hai kh (u lm xanh giy qum). Tkhi hica Z i vi H2bng 13,75. C cn dung dchY thu c khi lng mui khan l :

A.16,5 gam. B.14,3 gam.C.8,9 gam. D.15,7 gam.(thi tuyn sinh i hc khi A nm 2007)

Hng dn :

X phn ng vi dung dch NaOH gii phng hnhp kh Z gm hai cht kh u lm xanh giyqum, suy ra X gm hai mui amoni. Do trong

phn t c 2 nguyn tO nn cc mui amonic gc axit l RCOO.

V ZM 13, 75.2 27, 5= = nn Z cha mt cht lNH3, cht cn li l amin. Do cc mui amonichc 2 nguyn tC v gc axit phi c t nht 1nguyn tC nn amin l CH3NH2. Suy ra X gmCH3COONH4v HCOOH3NCH3.

3 4 3 3 2

3 3 3 2 2

CH COON H NaOH CH COONa NH H O

x (mol ) x (mol )

HCOOH NCH NaOH HCOONa CH NH H Oy (m ol ) y (m ol )

+ + +

+ + +

Z

Z

n 0,2 x y 0,2 x 0,05

17x 31y 5,5 y 0,15M 27,5

= + = =

+ = ==

Trong Y cha CH3COONa v HCOONa. Khi ccn dung dch Y thu c khi lng mui khanl :

3muoi CH COONa HCOONa

0,15.680,05.82

m m m 14,3 gam= + =14 2 4314 2 43

V d6:Hp cht X mch hc cng thc phnt l C4H9NO2. Cho 10,3 gam X phn ng vavi dung dch NaOH sinh ra mt cht kh Yv dung dch Z. Kh Y nng hn khng kh, lmgiy qutm m chuyn mu xanh. Dung dch Zc kh nng lm mt mu nc brom. C cndung dch Z thu c m gam mui khan. Gi trca m l

A.8,2. B.10,8. C.9,4. D.9,6.(thi tuyn sinh i hc khi A nm 2009)


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Hng dn :

X phn ng vi NaOH sinh ra kh Y, suy ra X lmui amoni. Gc axit trong X c hai nguyn tO nn c dng l RCOO.

Y nng hn khng kh v lm xanh giy qutmm, chng tY l amin v c sC nhhn hoc

bng 2, hoc nu c 3 nguyn t C th phi l(CH3)3N. Nhng nu Y l (CH3)3N th snguyntH trong X phi ln hn 9 (loi). Vy X phi lmui amoni ca amin c 1 hoc 2 nguyn tC.Dung dch Z c kh nng lm mt mu nc

brom, chng t trong Z cha mui Na ca axitcacboxylic khng no, c sC ln hn hoc bng3 hay Z cha mui HCOONa (natri fomat, c

nhm CHO). D thy Z khng th cha natrifomat v nh vy snguyn tC trong X ti achl 3.

Vy X l CH2=CHCOOH3NCH3, mui trongdung dch Z l CH2=CHCOONa.

Theo bo ton gc axit, ta c :

2 2 3 3

2

CH CH COON a CH CH COOH NCH

C H C H CO ON a

10,3n n 0,1

103

m 0,1.94 9,4 gam

= =

=

= = =

= =

V d 7: Hp cht hu c X c cng thcC2H8N2O4. Khi cho 12,4 gam X tc dng vi200 ml dung dch NaOH 1,5M, thu c 4,48 lt(ktc) kh X lm xanh qutm m. C cn dungdch sau phn ng thu c m gam cht rnkhan. Gi trca m l :

A. 17,2. B. 13,4.C. 16,2. D. 17,4.

(thi thi hc ln 1 THPT Qunh Lu 1 NghAn, nm hc 2012 2013)

Hng dn :X c cng thc phn tl C2H8N2O4, X tc dngvi dung dch NaOH thu c kh lm xanh giyqu tm m. Suy ra X l mui amoni ca aminhoc NH3. X ch c 2 nguyn t C v c 4nguyn t O nn gc axit trong X l

OOC COO . Cn 2 nguyn t N v 8

nguyn t H s tng ng vi hai gc4

NH + .

Vy X l4 4

NH OOC COONH (amoni oxalat)

Phng trnh phn ng :

4 2 2 3 2(COONH ) 2NaOH (COONa) 2NH 2H O+ + +

Cht rn thu c l NaOOCCOONa v c thcn NaOH d.

Theo bo ton nguyn tC v Na, ta c :

2 4 2

2

( COON a ) NaOH d2

( COON a) (COONH )

N aOH d N aOH ban au ( COON a)

0,3 0,1

chat ran

m m

n n 0,1

n n 2.n 0,1

m 0,1.134 0,1.40 17, 4 gam

= = = + =

= + =

1 42 43 14 2 43

14 2 43 1 2 3

V d8:Mt cht hu c X c cng thc phnt l C4H11NO2. Cho X tc dng hon ton vi100 ml dung dch NaOH 2M, sau phn ng thuc dung dch X v 2,24 lt kh Y (ktc). Nutrn lng kh Y ny vi 3,36 lt H2 (ktc) thc hn hp kh c t khi so vi H2 l 9,6.Khi lng cht rn thu c khi c cn dungdch X l

A. 8,62 gam. B. 12,3 gam.C. 8,2 gam. D. 12,2 gam.(thi thi hc ln 1 THPT Qut Lm

Nam nh, nm hc 2013 2014)

Hng dn :

4 11 2X (C H NO ) NaOH Y+ . Suy ra Y l

NH3hoc amin, X l mui amoni.

Theo githit, ta c :

2

2)

Y H

Y( Y , H

Y 2 5 2 3 2

3 3 2 5

3 2 3 2

n 0,1; n 0,15

0,1.M 0,15.2M 19,2

0,25

M 45, Y laC H NH hoac (CH ) NHCH COOH NC H

X laCH COOH N(CH )

= = +

= =

=

Ta c :

3

3

CH COONa X Y

N aOH d N aOH ban au CH COO Na

0,2 0,1

n n n 0,1

n n n 0,1

= = = = =

1 4 2 43 14 2 43


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CH COON a N aOH d3

chat ran

m m

m 0,1.82 0,1.40 12, 2 gam = + =1 2 3 1 2 3

V d9: Cht hu c X c cng thc phn t

C2H8N2O3. Cho 3,24 gam X tc dng vi 500 mldung dch KOH 0,1M. Sau khi kt thc phnng thu c cht hu c Y n chc v dungdch Z. C cn Z thu c khi lng cht rnl:

A.3,03. B.4,15. C.3,7 D.5,5.(thi thi hc ln 1 THPT Minh Khai

H Tnh, nm hc 2013 2014)

Hng dn :

C2H8N2O3(X) tc dng vi dung dch KOH thu

c cht hu c Y n chc, chng t X lmui amoni to bi NH3 hoc amin n chc.

Nh vy, gc axit trong X c 1 nguyn tN v 3

nguyn tO, l3

NO . Suy ra cng thc cu

to ca X l C2H5NH3NO3 (etylamoni nitrat)hoc (CH3)2NH2NO3(imetylamoni nitrat).

Theo bo ton nguyn tgc3

NO v bo ton

nguyn tK, ta c :

{

3 2 5 3 3 3 2 2 3

3

K N O C H N H N O h oac ( CH ) N H N O

K OH d K OH ban au K N O

0,030,05

n n 0,03

n n n 0,02

= =

= =

1 4 2 43

K NO K OH d3

chat ran

m m

m 0, 03.101 0, 02.56 4,15 gam = + =14 2 43 14 2 43

V d 10: Hp cht X c cng thc phn tC2H8O3N2. Cho 16,2 gam X phn ng ht vi400 ml dung dch KOH 1M. C cn dung dchthu c sau phn ng th c phn hi v

phn cht rn. Trong phn hi c cha amin achc, trong phn cht rn ch cha cc cht vc. Khi lng phn cht rn l :

A. 26,75 gam. B. 12,75 gam.C. 20,7 gam. D. 26,3 gam.

(thi thi hc ln 4 THPT Chuyn

i hc Vinh, nm hc 2012 2013)

Hng dn :

Theo gi thit, suy ra : X l mui amoni caamin hai chc. V X ch c 2 nguyn tC nn

gc amoni ca amin l3 2 3

H N CH NH+ + ,

phn cn li l CO3 chnh l gc2

3CO . Vy

cng thc cu to ca X l2 3 2 3

CH ( NH ) CO .

Phng trnh phn ng :

2 3 2 3 2 2 2 2 3 2CH (NH ) CO 2K OH CH (NH ) K CO 2H O+ + +

Cht rn thu c l K2CO3 v c th c cKOH d.

Theo bo ton nguyn tC v nguyn tK, tac:

{

2 3 2 3 2 3

2 3

K CO KOH d2 3

K CO CH ( NH ) CO

K OH d K OH ban au K CO

0,150,4

chat ran

m m

n n 0,15

n n 2.n 0,1

m 0,15.138 0,1.56 26, 3 gam

= =

= =

= + =

142 43

142 43 12 3

V d11:X c cng thc phn tC3H12N2O3. Xtc dng vi dung dch NaOH (un nng nh)hoc HCl u c kh thot ra. Ly 18,6 gam Xtc dng hon ton vi 400 ml dung dch NaOH1M. Sau phn ng c cn dung dch ri nungnng cht rn n khi lng khng i th cm gam. Gi trca m l :

A. 22,75. B. 19,9.C. 20,35. D. 21,20.

(thi thi hc ln 4 THPT Qunh Lu 1 NghAn, nm hc 2011 2012)

Hng dn :

X c cng thc phn t l C3H12N2O3. X tcdng vi HCl sinh ra kh, chng t X l mui

cacbonat hoc mui hirocacbonat. X tc dngvi NaOH sinh ra kh, chng t X l muiamoni. V X c cha 2 nguyn tN nn X c haigc amoni. Do gc axit trong X phi l

23

CO lin kt vi 2 gc amoni. Suy ra X c

cng thc cu to l (CH3NH3)2CO3(metylamoni cacbonat) hoc H4NCO3H3NC2H5hoc H4NCO3H2N(CH3)2.

Cht rn thu c cha Na2CO3ngoi ra cn cthc NaOH d.


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Theo bo ton gc cacbonat v Na, ta c :

2 3

2 3

Na CO N aOH d2 3

Na CO X

N aOH d N aOH ban au N a CO

0, 4 0,15

ch at ran

m m

18,6n n 0,15 mol

124

n n 2.n 0,1 mol

m 0,15.106 0,1.40 19, 9 gam

= = =

= =

= + =

1 4 2 43 1 2 3

14 2 43 1 2 3

V d12:Hn hp X gm cc cht c cng thcphn tl C2H7O3N v C2H10O3N2. Khi cho cccht trong X tc dng vi dung dch HCl hocdung dch NaOH d un nng nh u c khthot ra. Ly 0,1 mol X cho vo dung dch cha0,25 mol KOH. Sau phn ng c cn dung dch

c cht rn Y, nung nng Y n khi lngkhng i c m gam cht rn. Gi tr ca ml:

A. 16,9 gam. B. 17,25 gam.C. 18,85 gam. D. 16,6 gam.

(thi thi hc ln 1 THPT Lng cBng Thanh Ha, nmhc 2013 2014)

Hng dn :

V X tc dng vi HCl hoc NaOH un nng

u thy thot kh, suy ra : X l hn hp muiamoni ca amin hoc ca NH3vi axit cacbonic.C2H7O3N ch c 1 nguyn tN nn ch c mtgc amoni, suy ra cng thc cu to ca n lCH3NH3HCO3. C2H10O3N2c 2 nguyn tN nnc 2 gc amoni, suy ra cng thc cu to ca nl CH3NH3CO3H4N.

Theo bo ton gc cacbonat v nguyn tK, tac :

{

2 3 3 3 3 3 3 3 4

2 3

K CO K OH d2 3

K CO ( CH N H CO , CH N H CO H N)

K OH d K OH K CO

0,25 0,1

chat ran

m m

n n 0,1

n n 2 n 0,05

m 0,1.138 0, 05.56 16, 6 gam

= =

= =

= + =

1442443

1442443 1442443

4. Bi tp vn dngCu 1: Hai hp cht hu c X v Y c cngcng thc phn tl C3H7NO2, u l cht rn iu kin thng. Cht X phn ng vi dung

dch NaOH, gii phng kh. Cht Y c phn ngtrng ngng. Cc cht X v Y ln lt l

A.vinylamoni fomat v amoni acrylat.B.amoni acrylat v axit 2-aminopropionic.

C.axit 2-aminopropionic v amoni acrylat.D.axit 2-aminopropionic

v axit 3-aminopropionic.(thi tuyn sinh i hc khi B nm 2010)

Cu 2:Cho 1,38 gam X c cng thc phn tC2H6O5N2(l mui ca amino axit vi axitHNO3) phn ng vi 150 ml dung dch NaOH0,2M. Sau phn ng c cn dung dch thu cm gam cht rn Y. Gi trm l :

A.2,22 gam. B. 2,62 gam.C.2,14 gam. D.1,65 gam.

(thi thi hc ln 1 THPT chuynNguyn Hu H Ni, nm hc 2013 2014)

Cu 3:Cho 6,2 gam hp cht hu c X c cngthc phn t l C3H12O3N2 tc dng va vi100 ml dung dch NaOH 1M, thu c mt chthu c thkh c th tch l V lt (ktc) vdung dch Z ch cha cc cht v c, c cndung dch Z thu c m gam cht rn khan. Gitrca m v V ln lt l :

A. 2,24 v 9,3. B. 3,36 v 9,3.C. 2,24 v 8,4. D. 2,24 v 5,3.

(thi thi hc ln 1 THPT CmL

Bc Giang, nm hc 2013 2014)

Cu 4:X c cng thc C4H14O3N2. Khi cho Xtc dng vi dung dch NaOH th thu c hnhp Y gm 2 kh iu kin thng v u ckh nng lm xanh qu tm m. Mt khc, khi

cho 6,9 gam X tc dng hon ton vi 200 mldung dch NaOH 0,75M ri c cn dung dch thuc sau phn ng, thu c m gam cht rn.Gi trca m l

A. 7,3. B. 5,3. C. 8,25. D. 4,25.(thi thi hc ln 1 THPT

Chu Vn An H Ni, nm hc 2012 2013)

Cu 5:Cho 14,4 gam CH8O3N2phn ng honton vi 400 ml dung dch KOH 1M. C cn


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dung dch sau phn ng thu c m gam chtrn khan. Gi trca m l :

A.19,9. B.15,9.

C.21,9. D.26,3.(thi thi hc ln 2 THPT chuyn

Hng Vng Ph Th, nmhc 2013 2014)

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