IV. MOT SOH OP CHAT QUAN TRONG CUAN H6M 1 N h o m oxit, AljỌ,
11. Xla kim loai nhom IIẠ Cho 1,7 gam h6n hop gom Xva Zn tac dung vđ luong du dung djch HCl, sinh ra 0,672 lit khi H, (a dktc).
du dung djch HCl, sinh ra 0,672 lit khi H, (a dktc).
Mat khac, khi cho 1,9 gam X tac dung vdi luong du dung djch H, S 0 4 loang thi the tich khf H , sinh ra chua den 1,12 Ift (6 dktc).
Kim loii X la j i , ) / >
Ạ Mg. B. Cạ C. Bạ D. Sr.
Huang đn gidi •
Theobiira: = 0.03 mol; nH2< 0.05 mol.
M ( X , Z n ) + 2HC1 > MCỊ + H , , 0,03 mol 0,03 mol Theo F I P U : n^,, x. z„ = HH 2 = 0,03 mol. Suy ra: M = 1,7/0,03 = 56,67 Vi Mz„ = 65 > 56,67 =^ Mx < 56,67 (1) , ' X + H, S 0 4 ( loang) > XSO, + H , ; Theo PTPLT •.n^^^< 0,05 mol Ux < 0,05 mol
Phcin loai va pinfanfi phap f^idi nlianh BT Hoa hoc 12 —Ci) Thanh Toon
Tir { 1 , 2) ta c6: 38 < Mx < 56,67
Vay X la Ca ( M = 40). J)ap an diing la B.
12. Cho 7,1 gam hdii hofp gom mot kim loai kiem X va mot kim loai kiem tho Y tac dung het vdi lugiig du dung djch HCI loang, thu dugc 5,6 lit khi (dktc). K i m loai X, Y l a
Ạ natri va magiẹ B. kali va canxị C. liti va berị D. kali va barị
Huong dan gidi
Theo bai ra: n^^ = 0 , 2 5 ( m o l ) . i
i PTPÚ: X + H j O - ->XOH + - H , t Y + 2 H , 0 ) . Y ( O H ) , + H ^ t Suyra: < Ohhx.v < 2 . n H 2 =^ ^ ' 2 5 < n , , , , x , Y <0.5 14,2<Mx,Y <28,4 c 7,1 — 7,1 Suy ra: — < M X . Y < 0,5 " 0,25
vay Mx = 23 (natri); M y = 24 (magie). Dap an diing la Ạ
Chu y: * Xac dinh khoang gia tri so mol h6n hop kim loai kidni va ki6m th6: + r.hhmax khi chi c6 kim loai kiem: nhh,„„ = 2 n „ 2
+ n,,,,,,,;,, khi chi c6 kim loai ki6m tho: n h,,,,,!,, = n^.,
* Bai nay chi tim dugc 1 ket qua khi phan tir khoi kim loai kidm va kim loai kiem the! xap xi nhau (ciing chu ky).
13. Hoa tan hoarr-toan 2,45 gam h6n hgp g6m hai kim loai kiem tho vao 200 ml dung djch HCI 1,25M, thu dugc dung dich Y chua cac chat tan c6 n6ng do mol bring nhaụ Hai k i m loai trong X la
Ạ M g va Cạ B. Be va Cạ C. Be va M g . D. M g va Sr.
Hu&ng dan gidi
Theo bai ra: n,.jQ = 0 , 2 5 ( m o l ) .
- Vi cac chat tan c6 s6' mol bang nhau => so mol hai kim loai kiem tho bang nhaụ - Neu HCI vCra dii thi so mol m6i kim loai kiem th6 bang: 0,25/4 = 0,0625(nx)l).
Taco: (M^T, + M^y^ )O,0625 = 2,45 s = ^ M K T , + M K T 2 =39,2 i ^ l o a i
- Neu HCI du thi s6' mol m6i kim loai kiem tho bang: 0,25/ 5 = 0,05 (mol).
; Ta c6: (M^T, + M ^ x ^ )-0,05 = 2,45 ^ M ^ . ^ ^ + U^^^ = 49 .
Cty TNHH MTV DVVH Khaiii- Viet
vay M K T , = 9 ( B e ) va M ^ T . = 4 0 ( C a ) .
Hai kim loai trong X la Be va Cạ Dap an diing la B. j4 Cho 1,9 gam h6n hgp muoi cacbonat va hidrocacbonat ciia kim loai kiem M tac
dung het voi dung djch HCI (du), sinh ra 0,448 lit khi (o dktc). Xac dinh kim loai kiem M .
Huong dan gidi
Co the giai nhanh nhu sau: 19
( M + 6 1 ) < ^ J ^ = 95 < ( 2 M + 60) => 1 7 , 5 < M < 3 4 . vay M = 23 (kim loai kiem Na).
15. X la hgp kim cua hai kim loai gom kim loai ki^m M va kim loai k i l m the! R.
Lay 28,8 gam X hoa tan hoan toan vao nu6c, thu dugc 6,72 lit khi H^ (a dktc). Dem 2,8 gam L i luyen them vao 28,8 gam X thi phan tram khdi lucnig ciia L i trong hgp kim vCra luyen la 13,29%. K i m loai kidm th6 R trong hgp kim X la Ạ M g . B. Cạ C. Bạ D. Sr.
Huong dan gidi
Gia su trong hofp kim X khong c6 L i , thi % m^ trong hgp k i m moi phai la % ^ = 2^JU00% ^ ^ ^ I ^
28,8 + 2,8 => trong hgp kim X c6 kim loai kiem la L i .