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cho 3,2 g cuo tác dụng vừa đủ với dung dịch H2SO4 , 4,9%. Tính nồng độ phần trăm của dung dịch CuSO4
nCuO=0,04 mol
CuO + H2SO4 =>CuSO4 + H2O
0,04 mol=>0,04 mol=>0,04 mol
mH2SO4=0,04.98=3,92 gam
=>m dd H2SO4=3,92/4,9%=80 gam
mCuSO4 sau=0,04.160=6,4 gam
mdd CuSO4=3,2+80=83,2 gam
C% dd CuSO4=6,4/83,2.100%=7,69%
cho \(m_{CuO}=3,2g\Rightarrow n_{CuO}=\frac{3,2}{80}=0,04mol\)
PTHH:
CuO + H2SO4 -> CuSO4 + H2O
0,04mol----------->0,04mol--------->0,04mol
ta có: \(m_{H_2SO_4}=0,04.98=3,92g\)
\(C\%_{d^2H_2SO_{4_{ }}}=4,9\%\)
=. \(m_{d^2H_2SO_4}=\frac{m_{H_2SO_4}.100}{C\%}=\frac{3,92.100}{4,9}=80g\)
áp dụng ĐLBTKL ta có: \(m_{d^2CUSO_4}=m_{CuO}+m_{d^2H_2SO_4}=3,2+80=83,2g\)
\(m_{CuSO_4}=0,04.160=6,4g\)
\(\Rightarrow C\%_{d^2CuSO_4}=\frac{m_{CuSO_4}}{m_{d^2CuSO_4}}.100=\frac{6,4}{83,2}.100=7,69\%\)
nCuO=16/80=0,2(mol)
a) PTHH: CuO + H2SO4 -> CuSO4 + H2O
0,2___________0,2_____0,2(mol)
b) mCuSO4=160.0,2=32(g)
c) mH2SO4=0,2.98=19,6(g)
=>C%ddH2SO4= (19,6/100).100=19,6%
a, \(2HCl+Ba\left(OH\right)_2\rightarrow BaCl_2+2H_2O\)
b, \(n_{HCl}=0,06.0,1=0,006\left(mol\right)\)
Theo PT: \(n_{Ba\left(OH\right)_2}=\dfrac{1}{2}n_{HCl}=0,003\left(mol\right)\)
\(\Rightarrow V_{Ba\left(OH\right)_2}=\dfrac{0,003}{0,2}=0,015\left(l\right)=15\left(ml\right)\)
c, \(n_{BaCl_2}=\dfrac{1}{2}n_{Ba\left(OH\right)_2}=0,003\left(mol\right)\Rightarrow C_{M_{BaCl_2}}=\dfrac{0,003}{0,06+0,015}=0,04\left(M\right)\)
a, \(H_2SO_4+2KOH\rightarrow K_2SO_4+2H_2O\)
b, \(n_{KOH}=0,12.0,4=0,048\left(mol\right)\)
Theo PT: \(n_{H_2SO_4}=\dfrac{1}{2}n_{KOH}=0,024\left(mol\right)\)
\(\Rightarrow C_{M_{H_2SO_4}}=\dfrac{0,024}{0,08}=0,3\left(M\right)\)
c, \(n_{K_2SO_4}=\dfrac{1}{2}n_{KOH}=0,024\left(mol\right)\)
\(\Rightarrow C_{M_{K_2SO_4}}=\dfrac{0,024}{0,08+0,12}=0,12\left(M\right)\)
a) Na2CO3 + 2CH3COOH --> 2CH3COONa + CO2 + H2O
b) \(n_{CH_3COOH}=\dfrac{25.6\%}{60}=0,025\left(mol\right)\)
PTHH: Na2CO3 + 2CH3COOH --> 2CH3COONa + CO2 + H2O
0,0125<-----0,025------------>0,025------>0,0125
=> \(m_{Na_2CO_3}=0,0125.106=1,325\left(g\right)\)
c) \(m_{dd.sau.pư}=1,325+25-0,0125.44=25,775\left(g\right)\)
\(C\%_{dd.CH_3COONa}=\dfrac{0,025.82}{25,775}.100\%=7,95\%\)
a. \(Mg+H_2SO_4\rightarrow MgSO_4+H_2\)
b. \(n_{Mg}=\dfrac{7,2}{24}=0,3\left(mol\right)\)
=> \(C\%_{H_2SO_4}=\dfrac{0,3.98.100}{200}=14,7\%\)
Câu 1 :
Natri tan, lăn tròn trên mặt nước, xuất hiện khí không màu
$2Na + 2HCl \to 2NaCl + H_2$
Câu 2 :
a) $CaCO_3 + 2HCl \to CaCl_2 + CO_2 + H_2O$
b) $n_{CO_2} = \dfrac{3,36}{22,4} = 0,15(mol)$
$\Rightarrow n_{HCl} = 2n_{CO_2} = 0,15.2 =0,3(mol)$
$C_{M_{HCl}} = \dfrac{0,3}{0,2} = 1,5M$
c) $n_{CaCO_3} = n_{CO_2} = 0,15(mol)$
$\Rightarrow m_{NaCl} = 21 - 0,15.100 = 6\ gam$
a) \(CuO+H_2SO_4\rightarrow CuSO_4+H_2O\)
b) \(n_{CuO}=\dfrac{3,2}{80}=0,04\left(mol\right)=n_{H_2SO_4}=n_{CuSO_4}\)
\(m_{ddH_2SO_4}=\dfrac{0,04.98}{4,9\%}=80\%\)
\(m_{ddsaupu}=3,2+80=83,2\left(g\right)\)
=> \(C\%_{CuSO_4}=\dfrac{0,04.160}{83,2}.100=7,69\%\)