- Dieii die kim logi kiem: Dien phan mud'i clorua hoac hidroxit nong chaỵ Dien che kim logi kiem tho: Dien phan mu6'i clorua nong chaỵ
1. Nguyen tac cua phiron gp hap
Kh6'i luang phan tir (hoSc nguyen tir) trung binh M cua h6n hop cac chat dugfc tinh theo cac cong thiJc:
1. M = - 1 ^ - = M , . n , + M , . n , + - + M,.n,
n,„ n ,+ n 2 + . . . + n.
Trong do: m^,^^•. kh6'i lugng cua h6n hgfp (gam); n,,!,: t6ng s6' mol cua h6n hap (mol);
M|, M , . . . Mj: khdi lirgng mol cac chát trong hdn hgp; n,, n2...n,: so mol tirong iJng cua tCing chat trong h 6 n hap. Noi each khac. M chinli la khoi luang mol trung binh cua hSn hap.
2. Ddi vdi chat khi, v i the tich ti le vai so mol ntn cdng thiic (1) c6 ihi
viet dirdi dang:
- _ M , V . + M , . V , + - + M,.V, V , + V , + . . . + V, V , + V , + . . . + V,
3. M = M, x , + M2X2+...+ MiXi (3)
Trong do: x,, Xj-.-x, la phAn tram sd mol cua cac chát.
Chii y: x cf day biéu ditn theo thap phan. Thi du x, = 0,25, tire la ehiém
25%, va nhu vay khi x = 1 urng vdi 100%.
4. Neu hdn hgp chi c6 hai chat thi cdng thiic (1) trd thanh: — ^ M|.n, +M2.n2 ^ M|n, + M 2( n - n , )
n^+n^ n Trong do: n la sd mol hdn hgp.
Cdng thiic (2) cd dang: V
Trong do: V la the tich hdn hgp.
Thi du Ị Hoa tan 2,84 gam hdn hgp 2 mudi canxi cacbonat va magie cacbonat bang dung dich HCl tháy cd 672 ml khi COj bay ra (dktc).
Thanh phSn % khdi lugng ciia mdi mudi trong hdn hgp la Ạ 70,42% CaCÔ va 29,58% MgCỘ
B. 29.6% CaCO:, va 70,4% MgCO,. C. 56,5% CaCO, va 43,5% MgCO,. D. 43,5% CaCO, va 56,5% MgCO,.
Hu&ng đn gidi: Dap an dung la Ạ Cac phuang trlnh hoa hoc:
CaCO, + 2 H C 1 ^ C a C l 2 + C O 21 + H 2 O (1)
MgCO, + 2 H C 1 - > M g C l 2 + C 0 2 t + H 2 O (2)
Theo (1,2): Sd mol hdn hgp = sd mol C O 2 = = 0,03 (mol} 22,4
Khdi lugng mol trung binh cua hdn hgp:
- - 2,84 lOOn,+84(0,03-n,) , , M —— = L—\ (n, la so mol CaCO,j 0,03 0,03 > ^ 1 n, = 0,02 mol. 0,02.100 2,84 Vay % mc,a,, = - - ^ ^ ^ • 100% = 70,42% % m^^co, = 100 - 70,42 = 29,58%
Thi dii 2. Trong tu nhien, nguyfin td Cu cd hai đng vi la ^^Cu va
%Cụ Nguyen tit khdi trung binh ciia Cu la 63,54.
Thanh phSn % tdng sd nguydn tii cua đng vi ^Cu la
Ạ 73%. B. 50%
C. 54% D.27%.
Hu&ng đn gidi: Dap an diing la Ạ
Ggi X la tdng sd nguyen tir đng vi ^f^Cụ Ta cd: 63x + 65(1 - x) = 63,54 x = 0,73 hay 73%.
Thi du 3. Hoa tan 28,4 gam hdn hgp 2 mudi cacbonat kirn loai kier. tho thudc 2 chu k i lien tidp trong BTH bang dung dich HCl du, thu dug 6,72 lit khf C O 2 (dktc).
Hai kim loai ki^m thd do Ik
Ạ Be va Mg. B. Mg va Cạ
C. Ca va Sr. D. Sr va Bạ
Hu&ng đn gidi: Dap an diing la B. Ggi CTPT ciia 2 mudi cacbonat la RCO,
RCO, + 2HC1 -> RCI2 + C 0 2 t + H 2 O (1)
6 72
— 2 8 4 MRCỌ = ^ = 9 4 , 6 7 . MRCỌ = ^ = 9 4 , 6 7 . 0 , 3 =>R +60 = 94,67 =>R = 34,67 R, = 24=^,R, l a M g C R , < R ). R, = 40 => Ro la Ca ( R j > R ).
2. Phuang phap trung binh ap dung cho hoa hoc huru co
K h i ap dung phuang phap trung binh cho cac bai toan hoa hoc hiru co, ngucfi ta ma r6ng phuang phap nay thanh phiMng phap so n^iuyen tii
cachon trung binh (SNTCTB) hay so nguyen tic hidro trung binh
(SNTHTB).
Nguyen tdc cua nhirmg phap SNTCTB:
Gia sijr c6 h6n hop gom 2 olefin C„H2„ va C^Hj^, vdi s6' mol tuang ling a, b. Ta c6 thé xem h6n hop khi nay chi c6 1 olefin c6 s6' nguyfin tir cacbon la n ( C- H 3„ ) v a s6' mol bang a + b. D i nhien, n phai c6 gia t r i nam giua n va m, thi du n < iT < m.
Sau day la nhiJng thi du dien hinh suf dung phuang phap SNTCTB v6i cac d'liu kitn cho khac nhaụ