I .T HEO CHirONG TRNH CHUAN
56 gam 64 gam kh6'i luong tang 8gam.
kh6'i luong b6t ran trudrc, sau phan ung kh6ng thay d6i thi ti 16 m o l :
npe 1 '
TCf 66 tmh duoc % khd'i luong cua Zn trong h6n hop ban dSu : 65.8.100% 520.100% 0 ^ 7 0 ^
%m./ = = ~ 90,27%. 65.5 + 56 576
19.3. Dap an dung la C.
- Goi s6 mol ciia Fe va cua Cu trong 12 gam h6n hop la x. Ta c6 :
(56 + 64).x= 1 2 x = 0 , l .
- Gia su h6n hop X c6 a mol NO va b mol NO2. Ta c6 : 30a + 46b ,Q ^ ,
d v , u = = 19 a = b.
^'"^ 2(a + b)
Phuong trinh phan u:ng hoa tan Fe va Cu trong axit H N O 3 , tao ra NO va NO2 CO s6' mol bang nhau :
4Fe + I 8 H N O 3 4Fe(N03)3 + 3N0 + 3 N O 2 + 9 H 2 O (1) 4Cu + 1 2 H N O 3 4Cu(N03)2 + 2N0 + 2 N O 2 + 6 H 2 O ' (2)
Theo (1) : S6' mol (NO + N O 2 ) = - x = l,5x.
4 »
Theo ( 2 ) : S6' mol (NO + N O 2 ) = x.
S6' mol X = l,5x + X = 2,5x = 2,5.0,1 = 0,25 mol. -> Vx = 0,25.22,4 = 5,6 lit.
19.4. Dap an diing la Ạ
Cac phuang trinh phan ling :
Fe203 + 3 H 2 S O 4 F e 2 ( S 0 4 ) 3 + 3 H 2 O (1)
MgO + H 2 S O 4 -> MgS04 + H 2 O (2)
ZnO + H 2 S O 4 -> ZnS04 + H 2 O (3)
Theo djnh luat BTKL :
mx + mH2S04 = mmurti + niH^o -> m„,^, = rn^+ m^^^sô ~ my^^^ .
m„„,i = 2 , 8 1 - 4 , 9 - (0,05.18) = 6,81 (gam).
19.5. Dap an dung la D.
Phan tiJr chat X phai cd:
Ion N O 3: oxi h6a duac Cu trong dung dich H 2 S O 4 loang. Ion NH4 : tac dung v6i dung dich NaOH cho N H , bay rạ
19.6. Dap an dung la B.
Khi nhung hai thanh kim loai Pb va Sn dugc nd'i vdi nhau bang day d i n dien vao dung dich chat dien l i , ta c6 m6t pin dien hoạ Sn la kim loai hoat đng hon Pb nen Sn la cue am va bi an mon.
9.7. Dap an diing la C.
Cac phuong trinh phan ung:
2A1 + 6HC1 ^ 2 A I C I 3 + 3 H 2 t 0,1 mol 0,15 mol Cu + 4 H N O , -> Cu(N03)2 + 2 N O 2 + 2 H 2 O 0,15 mol 0,3 mol m = m^i + mc„ = 27.0,1 + 64.0,15 = 12,3 gam. 9.8. Dap an diing la C.
Cac phuang trinh phan ling:
(1) (2) Fe + 0,15 mol Cu + 0,075 mol 3Cu + 0,075 mol 4HNO, 0,6 mol 2Fe(NO03 0,15 mol 8HNO3 - 0,2 mol Fe(N03)3 + N O + 2 H 2 O 0,15 mol •> gu(N03)2 . + 2Fe(N03)2 3Cu(N03)2 + 2N0 + 4H2O (1) (2) (3)
Theo (1,2, 3): Thé tfch dung djch HNO, ft nhát cAn dung \k
0,6 + 0,2
1 = 0,8 lit.
^đHNO, ~ 9.9. Dap an diing la B.
Hai trudng hop xuát hien an mon dien hoa (su an mon c6 phat sinh dong dien) la thi nghiem 2 va thi nghiem 4.
19.10. Dap an diing la B. 19.11. Dap an diing la Ạ 19.11. Dap an diing la Ạ 19.12. Dap an diing la B. 19.13. Dap an diing la C. 19.14. Dap an diing la Ạ 19.15. Dap an diing la B.
19.16. Dap an dung la D.