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PTHH: \(CuSO_4+2NaOH\rightarrow Na_2SO_4+Cu\left(OH\right)_2\downarrow\)
Ta có: \(\left\{{}\begin{matrix}n_{CuSO_4}=0,08\cdot3,5=0,28\left(mol\right)\\n_{NaOH}=0,12\cdot1,5=0,18\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,28}{1}>\dfrac{0,18}{2}\) \(\Rightarrow\) CuSO4 còn dư
\(\Rightarrow\left\{{}\begin{matrix}n_{Na_2SO_4}=0,09\left(mol\right)=n_{Cu\left(OH\right)_2}\\n_{CuSO_4\left(dư\right)}=0,19\left(mol\right)\\\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{Na_2SO_4}=0,09\cdot142=12,78\left(g\right)\\m_{Cu\left(OH\right)_2}=0,09\cdot98=8,82\left(g\right)\\m_{CuSO_4\left(dư\right)}=0,19\cdot160=30,4\left(g\right)\end{matrix}\right.\)
Mặt khác: \(\left\{{}\begin{matrix}C_{M_{Na_2SO_4}}=\dfrac{0,09}{0,08+0,12}=0,45\left(M\right)\\C_{M_{CuSO_4\left(dư\right)}}=\dfrac{0,19}{0,08+0,12}=0,95\left(M\right)\end{matrix}\right.\)
\(a,HCl+NaOH\rightarrow NaCl+H_2O\\ b,n_{HCl}=\dfrac{3,65}{36,5}=0,1mol\\ n_{NaOH}=0,2.1=0,2mol\\ \Rightarrow\dfrac{0,1}{1}< \dfrac{0,2}{1}\Rightarrow NaOH.dư\\ n_{NaCl}=n_{NaOH,pư}=n_{HCl}=0,1mol\\ m_{NaOH,dư}=\left(0,2-0,1\right).40=4g\\ c,m_{NaCl}=0,1.58,5=5,85g\)
Ta có: \(n_{HCl}=0,2.1=0,2\left(mol\right)\)
\(n_{NaOH}=0,3.2=0,6\left(mol\right)\)
PT: \(HCl+NaOH\rightarrow NaCl+H_2O\)
Xét tỉ lệ: \(\dfrac{0,2}{1}< \dfrac{0,6}{1}\), ta được NaOH dư.
Theo PT: \(n_{NaOH\left(pư\right)}=n_{HCl}=0,2\left(mol\right)\)
\(\Rightarrow n_{NaOH\left(dư\right)}=0,6-0,2=0,4\left(mol\right)\)
\(\Rightarrow m_{NaOH\left(dư\right)}=0,4.40=16\left(g\right)\)
- Quỳ tím hóa xanh do NaOH dư.
a) \(n_{NaOH}=\dfrac{60.11,2\%}{40}=0,168\left(mol\right)\)
PTHH: \(2NaOH+MgCl_2\rightarrow Mg\left(OH\right)_2\downarrow+2NaCl\)
0,168---->0,084----->0,084
b) \(m_{kt}=m_{Mg\left(OH\right)_2}=0,084.58=4,872\left(g\right)\)
c) \(C\%_{MgCl_2}=\dfrac{0,084.95}{190}.100\%=4,2\%\)
\(n_{BaCl_2}=\dfrac{208.15\%}{208}=0,15\left(mol\right)\\ n_{H_2SO_4}=\dfrac{150.19,6\%}{98}=0,3\left(mol\right)\\ BaCl_2+H_2SO_4\rightarrow BaSO_4\downarrow+2HCl\\ Vì:\dfrac{0,15}{1}< \dfrac{0,3}{1}\Rightarrow H_2SO_4dư\\ n_{H_2SO_4\left(p.ứ\right)}=n_{BaSO_4}=n_{BaCl_2}=0,15\left(mol\right)\\ n_{HCl}=2.0,15=0,3\left(mol\right)\\ n_{H_2SO_4\left(dư\right)}=0,13-0,15=0,15\left(mol\right)\\ m_{HCl}=0,3.36,5=10,95\left(g\right)\\ m_{BaSO_4}=233.0,15=34,95\left(g\right)\\ m_{H_2SO_4\left(dư\right)}=0,15.98=14,7\left(g\right)\\ m_{ddsau}=208+150-34,95=323,05\left(g\right)\\ C\%_{ddHCl}=\dfrac{10,95}{323,05}.100\approx3,39\%\)
\(C\%_{ddH_2SO_4\left(dư\right)}=\dfrac{14,7}{323,05}.100\approx4,55\%\)
a,\(m_{BaCl_2}=208.15\%=31,2\left(g\right)\Rightarrow n_{BaCl_2}=\dfrac{31,2}{208}=0,15\left(mol\right)\)
\(m_{H_2SO_4}=150.19,6\%=29,4\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{29,4}{98}=0,3\left(mol\right)\)
PTHH: BaCl2 + H2SO4 → BaSO4 + 2HCl
Mol: 0,15 0,15 0,15 0,3
Ta có: \(\dfrac{0,15}{1}< \dfrac{0,3}{1}\) ⇒ BaCl2 hết, H2SO4 dư
\(m_{H_2SO_4dư}=\left(0,3-0,15\right).98=14,7\left(g\right)\)
b, \(m_{BaSO_4}=0,15.233=34,95\left(g\right)\)
\(m_{HCl}=0,3.36,5=10,95\left(g\right)\)
Đáp án C
Bảo toàn e : 2nCu = 2nSO2 => nSO2 = 0,2 mol
nNaOH = 0,4 mol = 2nSO2
=> Chỉ có phản ứng : 2NaOH + SO2 -> Na2SO3 + H2O
=> mNa2SO3 = 25,2g
Nhận thấy kết tủa lớn nhất khi có Mg(OH)2 : 0,06 mol và Al(OH)3 : 0,09 mol
nOH- = nH+ + 2×nMg2+ + 3×nAl3+ = 0,11 + 2×0,06 + 3×0,09 = 0,5 mol
→ 0,02V + 0,02V= 0,5 → V= 12,5 lít
Kết tủa nhỏ nhất khi chỉ có Mg(OH)2 : 0,06 mol
nOH- = nH+ + 2×nMg2+ + 4×nAl3+ = 0,11 + 2×0,06 + 4×0,09 = 0,59 mol
→ 0,02 V + 0,02V = 0,59 → V= 14,75 lit
Đáp án C
a, \(n_{NaOH}=0,2.0,3=0,06\left(mol\right)\)
\(m_{MgCl_2}=400.30\%=120\left(g\right)\Rightarrow n_{MgCl_2}=\dfrac{120}{95}=\dfrac{24}{19}\left(mol\right)\)
PT: \(2NaOH+MgCl_2\rightarrow Mg\left(OH\right)_2+2NaCl\)
Xét tỉ lệ: \(\dfrac{0,06}{2}< \dfrac{\dfrac{24}{19}}{1}\), ta được MgCl2 dư.
Theo PT: \(n_{MgCl_2\left(pư\right)}=\dfrac{1}{2}n_{NaOH}=0,03\left(mol\right)\Rightarrow n_{MgCl_2\left(dư\right)}=\dfrac{24}{19}-0,03=\dfrac{2343}{1900}\left(mol\right)\)
\(\Rightarrow m_{MgCl_2\left(dư\right)}=\dfrac{2343}{1900}.95=117,15\left(g\right)\)
b, Theo PT: \(\left\{{}\begin{matrix}n_{NaCl}=n_{NaOH}=0,06\left(mol\right)\\n_{Mg\left(OH\right)_2}=\dfrac{1}{2}n_{NaOH}=0,03\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{NaCl}=0,06.58,5=3,51\left(g\right)\\m_{Mg\left(OH\right)_2}=0,03.58=1,74\left(g\right)\end{matrix}\right.\)