C. b anot xayra sir oxi hoa: Cu > C u^^+2e
6. Day g6m cac kim loai d^u tac dung v6i n\x6 ca nhiet d6 thucmg tao ra cac dung
dich CO m6i truorng ki€m la
A . F e , K , C a B. Zn, Na, Ba C. L i , K, Ba D. Be, Na, Ca
Huong dan gidi
Cac kim loai nhom l A ( L i , Na, K, Rb, Cs, Fr) va m6t s6' kim loai nhom I I A (Ca,
Sr, Ba) tac dung dirge vdi H^O a d'liu kien thucnig tao ra dung djch kidm:
Li + H , 0 ^ LiOH + - H ,
Li + H.O -> K O H + - H ,
2 ^ Ba + 2H2O -> BăOH), +
=> Cac kim loai do c6 the la L i , K va Bạ Dap an dung la C. 7. Nguyen t6' R tao dugc oxit cao nhát c6 kh6'i lugng phan tif la lOOụ Nhan xet nao
sau day khong dung?
Ạ R la nguyen t6' nhom B
B. R dirge difiu che chii yeu theo phirong phap nhidt luydn. C. Cac hidroxit ciia R la hidroxit luong tính.
D. Nguyen tir R o trang thai 1 bin virng c6 6 electron d6c than.
Huong dan gidi
Oxit do la CrO, => R la kim loai Cr. Do do: - R la nguyen t6' nhom B (nhom V I B)
- PTPLT dieu che R: Cr203 + 2A1 > 2Cr + AI2O3
(Phuomg phap nhiet luyen: phuomg phap nhiet nh6m) - Tính chat axit - baza ciia hidroxit:
+ Cr(OH),: Co tính baza
+ Cr(OH)3: Co tính luomg tính
+ Cr02(OH)2 (H3Cr04, . . . ) : Co tính axit
- Cr (Z = 24) : [Ar] 3d'4s' (Co 6 electron doc than)
Dap an dung la C.
Nhan xet nao sau day khong dung?
A Khi pin dien hod boat dgng, a c&u mu6'i: ion duang chuyd'n djch ve anot, ion
am chuyen v^ eatot. i n . ' . . '
B. Cu, Fe, N i la nhom kim loai c6 thé d\iu che dugc theo ca ba phirong phap:
thuy luyen, nhiet luyen, dien phan.
C. Sir khac nhau ve ban chat giSa an mon hod hoc va an mon dien hod la cdch djch chuyin electron tir kim loai an mon sang m6i trucmg.
D. De lam giam nhiet do nong chay ciia A L O j , khi dien phdn nong chay A L O , nguori ta cho them SNaF.AlF, vaọ
Hu&ng dan gidi
Vai tro ciia edu muoi la trung hoa dien tich nen ion duong di chuyén catot
r +
M " +ne M va ion am di chuyén vi anot N - m e - ^ N "
Thi du: Zn - 2e —> Zn
A n o t ( - )
2 + V N 0 3 ; K ^ > C u ^ ^ + 2 e - > C u
i") ^"^^ Catot(+) "
Dap an dung la Ạ 9. Cho h6n hgp X g6m 2 kim loai tdc dung v6i dung djch H 2 S O 4 loang du, sau khi
phan ijfng ket thuc tháy khoi lugng h6n hgp X giam di mot nirạ H6n hgp X c6 thé la
Ạ A l v a F e B. A l va Ag C. Cu va A g D. Zn va Fe
Huong dan gidi
Suy ra trong X c6 1 kim loai tac dung vdi H2SO4 loang (dung tru6c H trong day dien hoa) va 1 kim loai khong tde dung vori H2SO4 loang (dumg sau H)
=>H6n hgp X c6 the la A l va Ag:
2 A l + 3H2S04(l) ^ A l 2(S04)3+ 3 H 2 '
A g + H2S04(l)-> khong xayrạ Dap an dung la B.
Chii v; - Cdc kim loai Fe, Zn, deu tac dung voi H2SO4 loang:
Fe + H2S04(l)->FeS04 + H2 ' v - Zn + H 2 S 0 4 ( l ) ^ Z n S 0 4 + H2 ' ^
- Cac kim loai Cu, Ag,... khdng tac dung v6i H2SO4 loang.