Hoà tan hoàn toàn 5g CaCO3 bằng 100g dd HCl 3,65%. Tính C% các chất thu được trong dd sau phản ứng. Cảm ơn mọi người rất nhiều
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\(m_{ct}=\dfrac{5.200}{100}=10\left(g\right)\)
\(n_{NaOH}=\dfrac{10}{40}=0,25\left(mol\right)\)
Pt : \(NaOH+HCl\rightarrow NaCl+H_2O|\)
1 1 1 1
0,25 0,25 0,25
a) \(n_{HCl}=\dfrac{0,25.1}{1}=0,25\left(mol\right)\)
\(m_{HCl}=0,25.36,5=9,125\left(g\right)\)
\(m_{ddHCl}=\dfrac{9,125.100}{3,65}=250\left(g\right)\)
b) \(n_{NaCl}=\dfrac{0,25.1}{1}=0,25\left(mol\right)\)
⇒ \(m_{NaCl}=0,25.58,5=14,625\left(g\right)\)
\(m_{ddspu}=200+250=450\left(g\right)\)
\(C_{NaCl}=\dfrac{14,625.100}{450}=3,25\)0/0
Chúc bạn học tốt
a) \(n_{NaOH}=\dfrac{200.5\%}{40}=0,25\left(mol\right)\)
PTHH: NaOH + HCl → NaCl + H2O
Mol: 0,25 0,25 0,25
\(m_{ddHCl}=\dfrac{0,25.36,5.100}{3,65}=250\left(g\right)\)
b) mdd sau pứ = 200 + 250 = 450 (g)
\(C\%_{ddNaCl}=\dfrac{0,25.58,5.100\%}{450}=3,25\%\)
\(n_{HCl}=\dfrac{3,65\%.100}{100\%.36,5}=0,1\left(mol\right)\)
Pt : \(2Na+2HCl\rightarrow2NaCl+H_2\)
0,15 0,1 0,1 0,05
Xét tỉ lệ : \(\dfrac{0,15}{2}>\dfrac{0,1}{2}\Rightarrow Nadư\)
\(m_{ddspu}=0,15.23+100-0,05.2=103,35\left(g\right)\)
\(C\%_{NaCl}=\dfrac{0,1.58,5}{103,35}.100\%=5,66\%\)
Chúc bạn học tốt
\(n_{HCl}=\dfrac{100.3,65}{100}:3,65=0,1mol\)
\(2Na+2H_2O\rightarrow2NaOH+H_2\)
0,15 0,15 0,075
\(NaOH+HCl\rightarrow NaCl+H_2O\\ \Rightarrow\dfrac{0,15}{1}>\dfrac{0,1}{1}\Rightarrow NaOH.dư\\ n_{HCl}=n_{NaOH}=n_{NaCl}=0,1mol\\ m_{dd}=0,15.23+100-0,075.2=103,3g\\ C_{\%NaCl}=\dfrac{0,1.58,5}{103,3}\cdot100=5,66\%\\ C_{\%NaOH\left(dư\right)}=\dfrac{\left(0,15-0,1\right).40}{103,3}\cdot100=1,94\%\)
\(n_{Na}=\dfrac{6,9}{23}=0,3\left(mol\right)\\ m_{HCl}=200.3,65\%=7,3\left(g\right)\\ n_{HCl}=\dfrac{7,3}{36,5}=0,2\left(mol\right)\)
\(PTHH:2Na+2HCl\rightarrow2NaCl+H_2\uparrow\\ LTL:0,3>0,2\Rightarrow Na.dư\)
Theo pt: nH2 = 2nHCl = 2.0,2 = 0,4 (mol)
VH2 = 0,4.22,4 = 8,96 (l)
Theo pt: nNaCl = nNa (phản ứng) = nHCl = 0,2 (mol)
=> \(\left\{{}\begin{matrix}m_{NaCl}=0,2.58,5=11,7\left(g\right)\\m_{Na\left(dư\right)}=\left(0,3-0,2\right).23=2,3\left(g\right)\\m_{H_2}=0,4.2=0,8\left(g\right)\end{matrix}\right.\)
=> \(m_{dd}=200+6,9-2,3-0,8=203,8\left(g\right)\)
=> C%NaCl = \(\dfrac{11,7}{203,8}=5,74\%\)
PTHH: \(CaO+2HCl\rightarrow CaCl_2+H_2O\) (1)
\(CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2\uparrow\) (2)
a) Ta có: \(n_{CO_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)=n_{CaCO_3}\)
\(\Rightarrow m_{CaCO_3}=0,2\cdot100=20\left(g\right)\) \(\Rightarrow\%m_{CaCO_3}=\dfrac{20}{25,6}\cdot100\%=78,125\%\)
\(\Rightarrow\%m_{CaO}=21,875\%\)
b) Theo 2 PTHH: \(\left\{{}\begin{matrix}n_{HCl\left(2\right)}=2n_{CaCO_3}=0,4mol\\n_{HCl\left(1\right)}=2n_{CaO}=2\cdot\dfrac{25,6-20}{56}=0,2mol\end{matrix}\right.\)
\(\Rightarrow\Sigma n_{HCl}=0,6mol\) \(\Rightarrow C\%_{HCl}=\dfrac{0,6\cdot36,5}{210\cdot1,05}\cdot100\%\approx9,93\%\)
a, PT: \(CaCO_3+2HCl\rightarrow CaCl_2+CO_2+H_2O\)
\(MgCO_3+2HCl\rightarrow MgCl_2+CO_2+H_2O\)
Ta có: 100nCaCO3 + 84nMgCO3 = 14,2 (1)
Theo PT: \(n_{CO_2}=n_{CaCO_3}+n_{MgCO_3}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{CaCO_3}=0,1\left(mol\right)\\n_{MgCO_3}=0,05\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{CaCO_3}=\dfrac{0,1.100}{14,2}.100\%\approx70,42\%\\\%m_{MgCO_3}\approx29,58\%\end{matrix}\right.\)
b, Theo PT: \(n_{HCl}=2n_{CO_2}=0,3\left(mol\right)\Rightarrow C_{M_{HCl}}=\dfrac{0,3}{0,6}=0,5\left(M\right)\)
PTHH :
\(CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2\)
x 2x x x x
\(MgCO_3+2HCl\rightarrow MgCl_2+H_2O+CO_2\uparrow\)
y 2y y y y
Có:
\(\left\{{}\begin{matrix}100x+84y=14,2\\x+y=\dfrac{3,36}{22,4}=0,15\end{matrix}\right.\)
\(\Rightarrow x=0,1;y=0,05\)
\(a,\%m_{CaCO_3}=0,1.100:14,2.100\%\approx72,423\%\)
\(\%m_{MgCO_3}=100\%-72,423\%\approx29,577\%\)
\(b,C_{M\left(HCl\right)}=\dfrac{0,2+0,1}{0,6}=0,5\left(M\right)\)
\(a)2Al+6HCl\rightarrow2AlCl_3+3H_2\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ b)n_{H_2}=\dfrac{5,6}{22,4}=0,25mol\\ n_{Al}=a;n_{Fe}=b\\ \left\{{}\begin{matrix}3a+b=0,25\\27a+56b=8,3\end{matrix}\right.\\ a=\dfrac{19}{470};b=\dfrac{121}{940}\\ \%m_{Al}=\dfrac{\dfrac{19}{470}\cdot27}{8,3}\cdot100=13,15\%\\ \%m_{Fe}=100-13,15=86,85\%\\ c)n_{HCl}=3\cdot\dfrac{19}{470}+2\cdot\dfrac{121}{940}=\dfrac{89}{235}mol\\ m_{ddHCl=}=\dfrac{\dfrac{89}{235}\cdot36,5}{7,3}\cdot100=189g\\ d)n_{AlCl_3}=n_{Al}=\dfrac{19}{470}mol\\ n_{Fe}=n_{FeCl_2}=\dfrac{121}{940}mol\)
\(m_{dd}=8,3+189-0,25.2=196,8g\\ C_{\%AlCl_3}=\dfrac{\dfrac{19}{470}\cdot133,8}{196,8}\cdot100=2,8\%\\ C_{\%FeCl_2}=\dfrac{\dfrac{121}{940}127}{196,8}\cdot100=8,3\%\)
a) \(n_{CO_2}=\dfrac{0,4958}{24,79}=0,02\left(mol\right);n_{HCl}=0,6.1=0,6\left(mol\right)\)
PTHH: \(CaCO_3+2HCl\rightarrow CaCl_2+CO_2+H_2O\)
0,02<------0,04<----0,02<-----0,02
\(\Rightarrow n_{HCl\left(p\text{ư}\right)}< n_{HCl\left(b\text{đ}\right)}\left(0,04< 0,6\right)\Rightarrow HCl\) dư, \(CaCO_3\) tan hết
\(\Rightarrow\left\{{}\begin{matrix}m_{CaCO_3}=0,02.100=2\left(g\right)\\m_{CaSO_4}=5-2=3\left(g\right)\end{matrix}\right.\)
b) dd sau phản ứng có: \(\left\{{}\begin{matrix}n_{HCl\left(d\text{ư}\right)}=0,6-0,04=0,56\left(mol\right)\\n_{CaCl_2}=0,02\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}C_{M\left(HCl\left(d\text{ư}\right)\right)}=\dfrac{0,56}{0,6}=\dfrac{14}{15}M\\C_{M\left(CaCl_2\right)}=\dfrac{0,02}{0,6}=\dfrac{1}{30}M\end{matrix}\right.\)
\(n_{CaCO_3}=0,05\left(mol\right)\)
\(n_{HCl}=\dfrac{100.3,65\%}{36,5.100\%}=0,1\left(mol\right)\)
\(CaCO_3+2HCl-->CaCl_2+H_2O+CO_2\uparrow\)
\(\dfrac{0,05}{1}=\dfrac{0,1}{2}\) => 2 chất hết
dd sau phản ứng CaCl2
\(C\%CaCl_2=\dfrac{0,1.36,5}{5+100-0,05.44}.100\%\approx3,55\%\)