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PTHH: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\)
Ta có: \(n_{H_2SO_4}=0,2\cdot1,5=0,3\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{Al}=0,2\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=0,1\left(mol\right)\\n_{H_2}=0,3\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{Al}=0,2\cdot27=5,4\left(g\right)\\V_{H_2}=0,3\cdot22,4=6,72\left(l\right)\\C_{M_{Al_2\left(SO_4\right)_3}}=\dfrac{0,1}{0,2}=0,5\left(M\right)\end{matrix}\right.\)
\(\left(a\right)2Al+3H_2O\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ \left(b\right)n_{H_2}=\dfrac{13,44}{22,4}=0,6mol\\ n_{Al}=\dfrac{0,6.2}{3}=0,4mol\\ m_{Al}=0,4.27=10,8g\\ \left(c\right)n_{O_2}=\dfrac{4,8}{32}=0,15mol\\ 4Al+3O_2\underrightarrow{t^0}2Al_2O_3\\ \Rightarrow\dfrac{0,4}{4}>\dfrac{0,15}{3}\Rightarrow Al.dư\\ n_{Al_2O_3}=\dfrac{0,15.2}{3}=0,1mol\\ m_{oxit}=m_{Al_2O_3}=0,1.102=10,2g\)
a: \(2Al+3H_2SO_4\rightarrow1Al_2\left(SO_4\right)_3+3H_2\uparrow\)
0,4 0,6 0,2 0,6
b: \(n_{H_2}=\dfrac{13.44}{22.4}=0.6\left(mol\right)\)
=>\(n_{Al}=0.4\left(mol\right)\)
\(m_{Al}=0.4\cdot27=10.8\left(g\right)\)
c: \(4Al+3O_2\rightarrow2Al_2O_3\)
0,4 0,2
\(m_{Al_2O_3}=0.2\left(27\cdot2+16\cdot3\right)=0.2\cdot102=20.4\left(g\right)\)
PTHH: \(Mg+H_2SO_4\rightarrow MgsO_4+H_2\uparrow\)
Ta có: \(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)=n_{MgSO_4}=n_{H_2SO_4}\) \(\Rightarrow\left\{{}\begin{matrix}m_{MgSO_4}=0,2\cdot120=24\left(g\right)\\V_{H_2}=0,2\cdot22,4=4,48\left(l\right)\\C\%_{H_2SO_4}=\dfrac{0,2\cdot98}{294}\cdot100\%\approx6,67\%\end{matrix}\right.\)
\(2Al+3H_2SO_4 \to Al_2(SO_4)_3+3H_2\\ n_{Al}=0,4(mol)\\ a/\\ n_{H_2}=\frac{3}{2}.0,4=0,6(mol)\\ V_{H_2}=0,6.22,4=13,44(l)\\ b/\\ n_{H_2SO_4}=n_{H_2}=0,6(mol)\\ n_{ddH_2SO_4}=\frac{0,6.98.100}{20}=294(g)\\ c/\\ n_{Al_2(SO_4)_3}=0,2(mol)\\ C\%_{Al_2(SO_4)_3}=\frac{0,2.342}{10,8+294-0,6.2}.100\%=22,52\%\)
1)
\(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
PTHH: 2Al + 3H2SO4 --> Al2(SO4)3 + 3H2
____0,1----->0,15
=> mH2SO4 = 0,15.98 = 14,7(g)
=> \(C\%=\dfrac{14,7}{250}.100\%=5,88\%\)
2)
\(n_{Na_2CO_3}=\dfrac{21,2}{106}=0,2\left(mol\right)\)
PTHH: Na2CO3 + 2HCl --> 2NaCl + CO2 + H2O
_______0,2------------------------------>0,2
=> VCO2 = 0,2.22,4 = 4,48(l)
3)
\(n_A=\dfrac{18,4}{M_A}\left(mol\right)\)
PTHH: 2A + Cl2 --to--> 2ACl
____\(\dfrac{18,4}{M_A}\)---------->\(\dfrac{18,4}{M_A}\)
=> \(\dfrac{18,4}{M_A}\left(M_A+35,5\right)=46,8=>M_A=23\left(Na\right)\)
4)
nHCl = 0,2.3 = 0,6(mol)
PTHH: M + 2HCl --> MCl2 + H2
____0,3<-----0,6
=> \(M_M=\dfrac{7,2}{0,3}=24\left(Mg\right)\)
a, PT: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)
Ta có: \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
Theo PT: \(n_{Zn}=n_{H_2SO_4}=n_{ZnCl_2}=n_{H_2}=0,15\left(mol\right)\)
b, mZn = 0,15.65 = 9,75 (g)
c, CM (H2SO4) = 0,15/0,05 = 3 M
d, mZnSO4 = 0,15.161 = 24,15 (g)
Bạn tham khảo nhé!
Câu 5 :
Phương pháp : Cho từ từ dung dịch $H_2SO_4$ đặc vào nước. Tuyệt đối không làm ngược lại do gây nguy hiểm.
Câu 6 :
a) $n_{Al} = \dfrac{5,4}{27} = 0,2(mol)$
$2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
$b) n_{Al_2(SO_4)_3} = \dfrac{1}{2}n_{Al} = 0,1(mol)$
$m_{Al_2(SO_4)_3} = 0,1.342 = 34,2(gam)$
c)$n_{H_2SO_4} = \dfrac{3}{2}n_{Al} = 0,3(mol)$
$1600\ ml = 1,6\ lít$
$C_{M_{H_2SO_4}} = \dfrac{0,3}{1,6} = 0,1875M$
d) $n_{H_2} = n_{H_2SO_4} = 0,3(mol)$
$V_{H_2} = 0,3.22,4 = 6,72(lít)$
Câu 5: Bn có thể vào xem SGK lớp 9 nhé
Câu 6:
Ta có: \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)
a. PTHH: 2Al + 3H2SO4 ---> Al2(SO4)3 + 3H2
Theo PT: \(n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}.n_{Al}=\dfrac{1}{2}.0,2=0,1\left(mol\right)\)
=> \(m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2\left(g\right)\)
b. Theo PT: \(n_{H_2SO_4}=\dfrac{3}{2}.n_{Al}=\dfrac{3}{2}.0,2=0,3\left(mol\right)\)
Đổi 1600ml = 1,6 lít
=> \(C_{M_{H_2SO_4}}=\dfrac{0,3}{1,6}=0,1875M\)
c. Theo PT: \(n_{H_2}=n_{H_2SO_4}=0,3\left(mol\right)\)
=> \(V_{H_2}=0,3.22,4=6,72\left(lít\right)\)