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a, PT: \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
b, Ta có: \(n_{Fe}=\dfrac{19,6}{56}=0,35\left(mol\right)\)
Theo PT: \(n_{H_2}=n_{Fe}=0,35\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,35.22,4=7,84\left(l\right)\)
c, Ta có: \(n_{CuO}=\dfrac{12}{80}=0,15\left(mol\right)\)
PT: \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
Xét tỉ lệ: \(\dfrac{0,15}{1}< \dfrac{0,35}{1}\), ta được H2 dư.
Theo PT: \(n_{H_2\left(pư\right)}=n_{CuO}=0,15\left(mol\right)\)
\(\Rightarrow n_{H_2\left(dư\right)}=0,35-0,15=0,2\left(mol\right)\)
\(\Rightarrow m_{H_2\left(dư\right)}=0,2.2=0,4\left(g\right)\)
`Fe_2O_3+3H_2SO_4->Fe_2(SO_4)_3+3H_2O`
0,0625----------0,1875---------0,0625 mol
`->n_(Fe_2O_3)=10/160=0,0625mol`
`->m_(Fe_2(SO_4)_3)=0,0625.400=25g`
`->C%(H_2SO_4)=((0,1875.98)/(450)).100%=4,083%`
`#YBtran<3`
\(n_{Fe_2O_3}=\dfrac{10}{160}=0,0625\left(mol\right)\\ Fe_2O_3+3H_2SO_4\rightarrow Fe_2\left(SO_4\right)_3+3H_2O\\ n_{Fe_2\left(SO_4\right)_3}=n_{Fe_2O_3}=0,0625\left(mol\right)\\ a,m=m_{Fe_2\left(SO_4\right)_3}=400.0,0625=25\left(g\right)\\ b,n_{H_2SO_4}=3.0,0625=0,1875\left(mol\right)\\ C\%_{ddH_2SO_4}=\dfrac{0,1875.98}{450}.100\%\approx4,083\%\)
a, \(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right);n_{H_2SO_4}=\dfrac{49}{98}=0,5\left(mol\right)\)
Ta có: \(\dfrac{0,3}{1}< \dfrac{0,5}{1}\) ⇒ Fe hết, H2SO4 dư
PTHH:Fe + H2SO4 ----> FeSO4 + H2
Mol: 0,3 0,3 0,3
\(m_{H_2SO_4dư}=\left(0,5-0,3\right).98=19,6\left(g\right)\)
b, \(V_{H_2}=0,3.22,4=6,72\left(l\right)\)
a. \(n_{Fe}=\dfrac{m}{M}=\dfrac{16,8}{56}=0,3\left(mol\right)\)
\(n_{H_2SO_4}=\dfrac{m}{M}=\dfrac{49}{98}=0,5\left(mol\right)\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)
1 : 1 : 1 (mol)
0,3 : 0,5 (mol)
-Chuyển thành tỉ lệ: \(\dfrac{0,3}{1}< \dfrac{0,5}{1}\Rightarrow\)Fe phản ứng hết còn H2SO4 dư.
\(m_{H_2SO_4\left(lt\right)}=n.M=\dfrac{0,3.1}{1}.98=29,4\left(g\right)\)
\(m_{H_2SO_4\left(dư\right)}=m_{H_2SO_4\left(tt\right)}-m_{H_2SO_4\left(lt\right)}=49-29,4=19,6\left(g\right)\)
b. -Theo PTHH trên: \(n_{H_2\left(đktc\right)}=\dfrac{0,3.1}{1}=0,3\left(mol\right)\)
\(V_{H_2\left(đktc\right)}=n.M=0,3.22,4=6,72\left(l\right)\)
\(BTKL:m_{Fe}+m_{H_2O_4}=m_{FeSO_4}+m_{H_2}\\ \Rightarrow m_{H_2}=11,2+19,6-30,4=0,4(g)\)
BTKL: \(m_{Fe}+m_{HCl}=m_{muối}+m_{H_2}\)
\(\Rightarrow m_{H_2}=5,6+7,3-12,7=0,2\left(g\right)\)
\(a,PTHH:2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\ \Rightarrow n_{Al}=\dfrac{2}{3}n_{H_2}=0,1\left(mol\right)\\ \Rightarrow m_{Al}=0,1\cdot27=2,7\left(g\right)\\ b,n_{H_2SO_4}=n_{H_2}=0,15\left(mol\right)\\ \Rightarrow m_{H_2SO_4}=0,15\cdot98=14,7\left(g\right)\\ c,n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{3}n_{H_2}=0,05\left(mol\right)\\ \Rightarrow m_{Al_2\left(SO_4\right)_3}=0,05\cdot342=17,1\left(g\right)\)
\(n_{Mg}=\dfrac{6}{24}=0,25\left(mol\right)\\
pthh:Mg+H_2SO_4->MgSO_4+H_2\)
0,25 0,25 0,25 0,25
\(m_{MgSO_4}=0,25.120=30\left(g\right)\)
\(n_{Fe_2O_3}=\dfrac{24}{160}=0,15\left(mol\right)\\
pthh:Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)
LTL : \(\dfrac{0,15}{1}>\dfrac{0,25}{3}\)
=> Fe dư , H2 hết
=> \(m_{Fe}=\dfrac{1}{6}.56=\approx9,3\left(g\right)\)
28g
Theo ĐLBTKL, ta có:
mFe + m\(H_2SO_4\) = m\(FeSO_4\) + mH\(_2\)
\(\Rightarrow m_{Fe}=\left(76+1\right)-49=28g\)
=> Đáp án D