cho 0.8g MgO tác dụng vừa đủ với 250ml dung dịch h2SO4
a) viết PTHH
b) tính khối lượng muối
c) tính nồng độ mol dd acid đã dùng
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Bài 2 :
\(n_{Fe_2O_3}=\dfrac{16}{160}=0,1\left(mol\right)\)
PTHH :
\(Fe_2O_3+3H_2SO_4\rightarrow Fe_2\left(SO_4\right)_3+3H_2O\)
0,1 0,3 0,1 0,3
\(m_{Fe_2\left(SO_4\right)_3}=0,1.400=40\left(g\right)\)
\(b,V_{ddH_2SO_4}=\dfrac{0,3}{2}=0,15\left(l\right)\)
\(c,C_{M\left(Fe_2\left(SO_4\right)_3\right)}=\dfrac{0,1}{0,15}=\dfrac{2}{3}\left(M\right)\)
Bài 3 :
\(n_{Mg}=\dfrac{4.8}{24}=0,2\left(mol\right)\)
PTHH :
\(Mg+H_2SO_4\rightarrow MgSO_4+H_2O\)
0,2 0,2 0,2 0,2
\(m_{MgSO_4}=0,2.120=24\left(g\right)\)
\(V_{H_2}=0,2.24,79=4,958\left(l\right)\)
\(c,C_{M\left(H_2SO_4\right)}=\dfrac{0,2}{0,2}=1\left(M\right)\)
\(d,C_{M\left(MgSO_4\right)}=\dfrac{0,2}{0,2}=1\left(M\right)\)
Bài 4 :
\(n_{Al}=\dfrac{8,1}{27}=0,3\left(mol\right)\)
PTHH :
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\)
0,3 0,45 0,15 0,45
\(V_{H_2}=0,45.24,79=11,1555\left(l\right)\)
\(m_{H_2SO_4}=0,45.98=44,1\left(g\right)\)
\(C\%_{H_2SO_4}=\dfrac{44,1}{300}.100\%=14,7\%\)
\(m_{Al_2\left(SO_4\right)_3}=0,15.342=51,3\left(g\right)\)
\(m_{dd}=8,1+300-\left(0,45.2\right)=307,2\left(g\right)\)
\(C\%_{Al_2\left(SO_4\right)_3}=\dfrac{51,3}{307,2}.100\%\approx16,7\%\)
Bài 5 :
\(n_{H_2}=\dfrac{4,958}{24,79}=0,2\left(mol\right)\)
PTHH:
\(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
0,2 0,4 0,2 0,2
\(m_{Fe}=0,2.56=11,2\left(g\right)\)
\(C_{M\left(HCl\right)}=\dfrac{0,4}{0,2}=2\left(M\right)\)
\(C_{M\left(FeCl_2\right)}=\dfrac{0,2}{0,2}=1\left(M\right)\)
\(Fe_2O_3=\dfrac{24}{160}=0,15\left(mol\right)\\ PTHH:Fe_2O_3+3H_2SO_4\rightarrow Fe_2\left(SO_4\right)_3+3H_2O\\ n_{Fe_2\left(SO_4\right)_3}=n_{Fe_2O_3}=0,15\left(mol\right)\\ a,m_{Fe_2\left(SO_4\right)_3}=400.0,15=60\left(g\right)\\ b,n_{H_2SO_4}=3n_{Fe_2O_3}=3.0,15=0,45\left(mol\right)\\ C_{MddH_2SO_4}=\dfrac{0,45}{0,2}=2,25\left(M\right)\\ c,V_{ddsau}=V_{ddH_2SO_4}=0,2\left(l\right)\\ C_{MddFe_2\left(SO_4\right)_3}=\dfrac{0,15}{0,2}=0,75\left(M\right)\)
\(n_{H_2SO_4}=0.25\cdot2=0.5\left(mol\right)\)
\(Na_2CO_3+H_2SO_4\rightarrow Na_2SO_4+CO_2+H_2O\)
\(0.5..............0.5...............0.5\)
\(m_{Na_2CO_3}=0.5\cdot106=53\left(g\right)\)
\(C_{M_{Na_2SO_4}}=\dfrac{0.5}{0.25}=2\left(M\right)\)
\(n_{CuO}=\dfrac{4}{80}=0,05\left(mol\right)\\a, CuO+H_2SO_4\rightarrow CuSO_4+H_2O\\ n_{CuSO_4}=n_{H_2SO_4}=n_{CuO}=0,05\left(MOL\right)\\ b,m_{CuSO_4}=0,05.160=8\left(g\right)\\ c,V_{ddH_2SO_4}=\dfrac{0,05}{0,5}=0,1\left(l\right)\\ d,V_{ddCuSO_4}=V_{ddH_2SO_4}=0,1\left(l\right)\\ C_{MddCuSO_4}=\dfrac{0,05}{0,1}=0,5\left(M\right)\)
250ml=0,25l
\(MgO+2HCl\rightarrow MgCl_2+H_2O\)
0.2.........0.4..........0,2............0,2 (mol)
a)
\(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
\(m_{MgCl_2}=0,2.95=19\left(g\right)\)
b)
\(C_{M_{HCl}}=\dfrac{0,4}{0,25}=1,6\left(M\right)\)
a/ \(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
PTHH: MgO + 2HCl → MgCl2 + H2O
Mol: 0,2 0,4 0,2
\(m_{MgCl_2}=0,2.95=19\left(g\right)\)
b/ \(C_{M_{ddHCl}}=\dfrac{0,4}{0,25}=1,6M\)
PTHH\(Na_2CO_3+2HCl\rightarrow2NaCl+H_2O+CO_2\)
tl............1................2.............2.............1.............1..(mol
br 0,1.................0,2......................................0,1(mol)
NaCl không phản ứng đc vsHCl
b)\(n_{CO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
\(C_{MHCl}=\dfrac{0,2}{0,4}=0,5\left(M\right)\)(đổi 400ml=0,4(l))
c)\(Tacom_{Na_2CO_3}=0,1.106=10,6\left(g\right)\)
\(\Rightarrow\%m_{Na_2CO_3}=\dfrac{10,6}{20}.100=53\%\)
\(\Rightarrow\%mNaCl=100\%-53\%=47\%\)