Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a)
$n_{Al} = 0,3(mol)$
$2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
Theo PTHH :
$n_{H_2SO_4} = \dfrac{3}{2}n_{Al} = 0,45(mol)$
$m_{dd\ H_2SO_4} = \dfrac{0,45.98}{12,25\%} = 360(gam)$
b)
$n_{H_2} = n_{H_2SO_4} = 0,45(mol)$
$V_{H_2} = 0,45.22,4 = 10,08(lít)$
c)
$n_{Al_2(SO_4)_3} = 0,15(mol)$
$m_{dd\ sau\ pư} = 8,1 + 360 - 0,45.2 = 367,2(gam)$
$C\%_{Al_2(SO_4)_3} = \dfrac{0,15.342}{367,2}.100\% = 14\%$
\(n_{Al}=\dfrac{1,35}{27}=0,05\left(mol\right)\\ 2Al+3H_2SO_4\rightarrow2Al_2\left(SO_4\right)_3+3H_2\\ n_{H_2SO_4}=n_{H_2}=\dfrac{3}{2}.0,05=0,075\left(mol\right)\\ n_{Al_2\left(SO_4\right)_3}=\dfrac{0,05}{2}=0,025\left(mol\right)\\ a,m_{Al_2\left(SO_4\right)_3}=342.0,025=8,55\left(g\right)\\ b,V_{H_2\left(đktc\right)}=0,075.22,4=1,68\left(l\right)\\ c,m_{H_2SO_4}=0,075.98=7,35\left(g\right)\)
\(n_{Al}=\dfrac{1,35}{27}=0,05mol\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
0,05 0,075 0,025 0,075
\(m_{Al_2\left(SO_4\right)_3}=0,025\cdot342=8,55g\)
\(V_{H_2}=0,075\cdot22,4=1,68l\)
\(m_{H_2SO_4}=0,075\cdot98=7,35g\)
\(a,n_{Al}=\dfrac{10,8}{27}=0,4\left(mol\right)\\ PTHH:2Al+3H_2SO_{4\left(loãng\right)}\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\\ Theo.pt:n_{H_2}=\dfrac{3}{2}n_{Al}=\dfrac{3}{2}.0,4=0,6\left(mol\right)\\ b,PTHH:RO+H_2\underrightarrow{t^o}R+H_2O\\ Mol:0,6\leftarrow0,6\rightarrow0,6\\ M_R=\dfrac{38,4}{0,6}=64\left(\dfrac{g}{mol}\right)\\ \Rightarrow R.là.Cu\)
a, PT: \(2Mg+O_2\underrightarrow{t^o}2MgO\)
\(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
\(Mg+H_2SO_4\rightarrow MgSO_4+H_2\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
b, Ta có: \(n_{O_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
Theo ĐLBT KL, có: m oxit = mKL + mO2 = 15,6 + 0,2.32 = 22 (g)
c, Gọi: \(\left\{{}\begin{matrix}n_{Mg}=x\left(mol\right)\\n_{Al}=y\left(mol\right)\end{matrix}\right.\) (trong 15,6 g)
⇒ 24x + 27y = 15,6 (1)
Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{Mg}+\dfrac{3}{4}n_{Al}=\dfrac{1}{2}x+\dfrac{3}{4}y=0,2\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=1,4\\y=-\dfrac{2}{3}\end{matrix}\right.\)
Đến đây thì ra số mol âm, bạn xem lại đề nhé.
Ta có: \(n_{Mg}=\dfrac{14,4}{24}=0,6\left(mol\right)\)
a, PT: \(Mg+H_2SO_4\rightarrow MgSO_4+H_2\)
_____0,6____________________0,6 (mol)
\(\Rightarrow V_{H_2}=0,6.22,4=13,44\left(l\right)\)
b, Ta có: \(n_{Fe_2O_3}=\dfrac{32}{160}=0,2\left(mol\right)\)
PT: \(Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)
Xét tỉ lệ: \(\dfrac{0,2}{1}=\dfrac{0,6}{3}\), ta được pư hết.
Theo PT: \(n_{Fe}=2n_{Fe_2O_3}=0,4\left(mol\right)\)
\(\Rightarrow m_{Fe}=0,4.56=22,4\left(g\right)\)
Bạn tham khảo nhé!
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
=> \(M_M=\dfrac{7,2}{0,3}=24\left(Mg\right)\)
Đáp án B
BTNT "H" ta có: nHCl = 2nH2 mol.
Đặt nH2 = x mol => nHCl = 2x mol
BTKL: m KL + mHCl = m muối + mH2
=> 5 + 2x.36,5 = 5,71 + 2x => x = 0,01
=> VH2 = 0,01.22,4 = 0,224 lit
PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
a, Ta có: \(n_{Al}=\dfrac{0,54}{27}=0,02\left(mol\right)\)
Theo PT: \(n_{H_2}=\dfrac{3}{2}n_{Al}=0,03\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,03.22,4=0,672\left(l\right)=672\left(cm^3\right)\)
⇒ Sai số: 672 - 660,8 = 11,2
b, Ta có: \(n_{H_2}=\dfrac{0,6608}{22,4}=0,0295\left(mol\right)\)
Theo PT: \(n_{Al}=\dfrac{2}{3}n_{H_2}=\dfrac{59}{3000}\left(mol\right)\)
\(\Rightarrow m_{Al}=\dfrac{59}{3000}.27=0,531\left(g\right)\)
⇒ Lượng tạp chất là: 0,54 - 0,531 = 0,009 (g)
Bạn tham khảo nhé!