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$m_{dung\ dịch}= D.V = 1,05.100 = 105(gam)$
$C\%_{Na_2CO_3} = \dfrac{5,2}{105}.100\% = 4,95\%$
Ta có: mdd= D.V= 1,05.100= 105(g)
C%ddNa2CO3= 5.2.100%/105=4,95%
a)
$Zn + 2HCl \to ZnCl_2 + H_2$
$n_{ZnCl_2} = n_{Zn} = \dfrac{6,5}{65} = 0,1(mol)$
$m_{ZnCl_2} = 0,1.136 = 13,6(gam)$
b)
$n_{HCl} = 2n_{Zn} = 0,2(mol) \Rightarrow C_{M_{HCl}} = \dfrac{0,2}{0,1} = 2M$
c)
CuO + H_2 \to Cu + H_2O$
$n_{CuO} = 0,125(mol) > n_{H_2} \to $ CuO$ dư
$n_{Cu} = n_{CuO\ pư} = n_{H_2} = 0,1(mol)$
$n_{CuO\ dư} = 0,125 - 0,1 = 0,025(mol)$
$\%m_{Cu} = \dfrac{0,1.64}{0,1.64 + 0,025.80}.100\% = 76,2\%$
$\%m_{CuO} = 23,8\%$
)
Zn+2HCl→ZnCl2+H2Zn+2HCl→ZnCl2+H2
nZnCl2=nZn=6,565=0,1(mol)nZnCl2=nZn=6,565=0,1(mol)
mZnCl2=0,1.136=13,6(gam)mZnCl2=0,1.136=13,6(gam)
b)
nHCl=2nZn=0,2(mol)⇒CMHCl=0,20,1=2MnHCl=2nZn=0,2(mol)⇒CMHCl=0,20,1=2M
c)
CuO + H_2 \to Cu + H_2O$
nCuO=0,125(mol)>nH2→nCuO=0,125(mol)>nH2→ CuO$ dư
nCu=nCuO pư=nH2=0,1(mol)nCu=nCuO pư=nH2=0,1(mol)
nCuO dư=0,125−0,1=0,025(mol)nCuO dư=0,125−0,1=0,025(mol)
%mCu=0,1.640,1.64+0,025.80.100%=76,2%%mCu=0,1.640,1.64+0,025.80.100%=76,2%
%mCuO=23,8%
\(n_{HCl}=\dfrac{73.4\%}{36,5}=0,08\left(mol\right)\\ MgO+2HCl\rightarrow MgCl_2+H_2O\\ 0,04........0,08.......0,04......0,04\left(mol\right)\\ m_{MgO}=0,04.40=1,6\left(g\right)\\ C\%_{ddMgCl_2}=\dfrac{0,04.95}{1,6+73-0,04.2}.100\approx5,099\%\)
\(m_{ct}=\dfrac{4.73}{100}=2,92\left(g\right)\)
\(n_{HCl}=\dfrac{2,92}{36,5}=0,08\left(mol\right)\)
Pt : \(MgO+2HCl\rightarrow MgCl_2+H_2O|\)
1 2 1 1
0,04 0,08 0,04
\(n_{MgO}=\dfrac{0,08.1}{2}=0,04\left(mol\right)\)
⇒ \(m_{MgO}=0,04.40=1,6\left(g\right)\)
\(n_{MgCl2}=\dfrac{0,08.1}{2}=0,04\left(mol\right)\)
⇒ \(m_{MgCl2}=0,04.95=3,8\left(g\right)\)
\(m_{ddspu}=1,6+73=74,6\left(g\right)\)
\(C_{MgCl2}=\dfrac{3,8.100}{74,6}=5,09\)0/0
Chúc bạn học tốt
Ta có: \(n_{O_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
a, PT: \(4Na+O_2\underrightarrow{t^o}2Na_2O\)
______0,8___0,2___0,4 (mol)
b, a = mNa = 0,8.23 = 18,4 (g)
c, mNaOH = 0,4.40 = 16 (g)
\(\Rightarrow C\%_{NaOH}=\dfrac{16}{150}.100\%\approx10,67\%\)
Bạn tham khảo nhé!
a) Gọi KL cần tìm là X
nHCl=\(\frac{5,6}{22,4}\)=0,25
PTHH: X + HCl \(\rightarrow\) XCl2 + H2
0,25 0,5 0,25 0,25
\(\Rightarrow\)mX = \(\frac{16.25}{0,25}\)=65g ( Zn )
b) mHCl= \(0,5.36,5\)=18.25g
mdd= \(\frac{18.25}{0,1825}\)=100g
Cm = \(\frac{0,5}{\frac{0,1}{0,2}}\)=6 mol/l
c) C% = 0,25.(65+71)/(100+16,25-0,5).100=29.73%
\(n_{CuSO_4}=\dfrac{50}{250}=0.2\left(mol\right)\)
\(n_{FeSO_4}=\dfrac{27.8}{278}=0.1\left(mol\right)\)
\(C_{M_{CuSO_4}}=C_{M_{FeSO_4}}=\dfrac{0.1}{0.1964}=0.5\left(M\right)\)
\(m_{dd_A}=50+27.8+196.4=274.2\left(g\right)\)
\(C\%_{CuSO_4}=\dfrac{0.1\cdot160}{274.2}\cdot100\%=6.47\%\)
\(C\%_{FeSO_4}=\dfrac{0.1\cdot152}{274.2}\cdot100\%=5.54\%\)
\(n_{CuSO_4.5H_2O}=\dfrac{50}{250}=0,2\left(mol\right)\)
=> \(m_{CuSO_4}=0,2.160=32\left(g\right)\)
\(m_{H_2O}=0,2.5.18=18\left(g\right)\)
\(n_{FeSO_4.7H_2O}=\dfrac{27,8}{278}=0,1\left(mol\right)\)=> \(m_{FeSO_4}=0,1.152=15,2\left(g\right)\)
\(m_{H_2O}=0,1.7.18=12,6\left(g\right)\)
\(m_{dd}=196,4+50+27,8=274,2\left(g\right)\)
\(V_{dd}=\dfrac{196,4+18+12,6}{1000}=0,227\left(l\right)\)
=> \(CM_{CuSO_4}=\dfrac{0,2}{0,227}=0,72M\)
\(C\%_{CuSO_4}=\dfrac{32}{274,2}.100=11,67\%\)
\(CM_{FeSO_4}=\dfrac{0,1}{0,227}=0,44M\)
\(C\%_{CuSO_4}=\dfrac{15,2}{274,2}.100=5,54\%\)
\(n_{Na_2O}=\dfrac{2,48}{64}=0,04\left(mol\right)\\ Na_2O+H_2O\rightarrow2NaOH\\ n_{NaOH}=0,04.2=0,08\left(mol\right)\\ C\%_{ddNaOH}=\dfrac{0,08.40}{240}.100\approx1,333\%\\ C_{MddNaOH}=\dfrac{0,08}{0,08}=1\left(M\right)\)