- Zn la nguyen t6'd c 62 electron hoa tri nhom IIB.
y4 7.38 Dap s6' diing la Ạ
7.38. Dap s6' diing la Ạ
Cac phucrng trinh phan ling :
Mg + 2HCI -> M g C l 2 + H j t (1) 2A1 + 6HC1 ^ 2 A I C I 3 + 3 H 2 t (2) 2A1 + 6HC1 ^ 2 A I C I 3 + 3 H 2 t (2) Cu + HCl : Kh6ng phan ling.
Chat ran Y la Cu, k h i X la H 2 .
Dung dich Z la MgCl2 va A I C I 3 .
S6 mol H2 : = = 0,35 mol.
Goi X va y la s6' mol M g A l trong h6n hap.
Ta CO : x + | y = 0,35 X = 0 , 0 5 [y = 0,2 24x + 2 7 y - 9 , 1 4 - 2 , 5 4
T h e o ( l ) v a(2) : nMgOz = ^Mg ^ mMgOz = 0-05 . 95 = 4,75 gam. n A i a , = " A l ^ m A i a , = 0'2 . 133,5 = 26,7 gam.
2 2 4
I
Vay : m = 4,75 + 26,7 = 32,45 gam. 7.39. Dap s6' dung la B.
Cic phuong trinh phan iJng :
2A1 + 6HC1 -> 2 A I C I 3 + 3 H 2 t
Mg + 2HC1 -> MgCl2 + H 21
F e + 2HC1 ^ F e C l 2 + H 21
H6n hop t i c dung v6i CUSO4 d i r :
2 A I + 3CUSO4 Al2(S04)3 + 3Cu Mg + CUSO4 MgS04 + Cu Fe + CUSO4 -> FeS04 + Cu
4 HNO3 + Cu Cu(N03)2 + 2 NO2 T + 2 H 2 O
Theo ( 1 , 2, 3) : A l , M g , Fe nhu6ng electron.
C u 2 +, thu electron. 2 H + + 2 e ^ H , t C u 2+ + 2 e ^2 Cu 13,44 22,4 = 1,2 mol. Theo ( 7 ) : R^^Q^ = 2 n c u = 2,4 mol . ^ V N O J = 2,4 . 22,4 = 5 3 , 7 6 lit. 7.40. Dap s6' dung la C.
Phucrng trinh phan irng nhiet nh6m : 2AI + Fe203 Tru6c p.u : 0,2 0,03 Phan umg : 0,06 0,03 Sau p.ir : 0,14 0 AI2O3 + 2Fe 0 , 0 3 0 , 0 3 0,06 0,06 ( 1 ) (2) ( 3 ) ( 4 ) ( 5 ) ( 6 ) (7) .:rụ:4 Kh6'i lucfng chát ran sau phan ihig :
7.41. Ddp s6'dung la Ạ
Ap dung phirorng phap bao toan electron, ta c6 :
Tdng s6 electron cho = (0,05 . 1) + (0,03 . 2) = 0,11 mol. 9 VA
Tdng s6' electron nhSn = 3 nNo + HNQZ = ' ^ ^ ^ ^ = 0,11 mol.
^ V , = ^ ^ ^ ^ = 1,369 Ih.
7.42. Dap s6' dung 1^ Ạ
Cac phuong trinh phan irng : ' 2A1 + Fe203 -> AI2O3 + 2Fe
2A1 + 3CuO -> AI2O3 + 3Cu
Ap dung phuong phap bao tôn electron, ta c6 : 0 54 (adsbygoogle = window.adsbygoogle || []).push({});
Tdng s6' mol electron A l cho = .3 = 0,06 mol. 27
Tuang tu Fê"" Cu^'^nhan = 3 nNo + " N O J =
-> V . 0.06A22.4 ^ 6
Thanh phSn cua NO NO2 1^ :
V N O = ^ 1 =0.224 l i t ; V N O = 0,672 l i t .
4 ^
7.43. Dap an dung 1^ Ạ
Gpi m la khd'i lupng thanh kim loai M , A la nguySn tu khd'i cua kim loai, X id s6 mol mu6'i phan urng :
M + C U S O 4 M S O 4 + Cu^
Kim loai M tan v^o dung dich, Cu thodt ra him vko thanh M . Do do : Ạx - 64.x = — .m (I)
100
T h e o ( l , 2 ) : = 2 . nn^ = 2 . = 1 mol. M + P b( N 0 3)2 M( N 0 3) 2+ P b i
Tuong tu trfin, ta c6 :207.x - Ax = — .m (II) 100
Giai he phuong trinh (I), (II), ta dupe : A = 65. Vay kim loai M 1^ Zn.
.44. Dap s6' dung la D.
C^c phuong trinh phan iJng :
Fe + 2HC1 ^ FeCl2 + H j t (1)
Mg + 2 H a MgCl2 + H 2 t (2). 11.2
22,4
Ap dung dinh luSt bao toan kh6'i lupng ta c6 : 2 0 + 1. 36,5 = nin^u^i + 2.0,5 -> m^^gj = 55,5 gam
45. Dap an diing la C. Phuong trinh phan ling :