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Ta có: \(n_{MgO}=\dfrac{40}{40}=1\left(mol\right)\)
\(n_{HCl}=0,5.1=0,5\left(mol\right)\)
PT: \(MgO+2HCl\rightarrow MgCl_2+H_2O\)
Xét tỉ lệ: \(\dfrac{1}{1}< \dfrac{0,5}{2}\), ta được MgO dư.
Theo PT: \(n_{MgCl_2}=\dfrac{1}{2}n_{HCl}=0,25\left(mol\right)\)
\(\Rightarrow C_{M_{MgCl_2}}=\dfrac{0,25}{0,5}=0,5\left(M\right)\)
\(Fe+CuSO_4\rightarrow FeSO_4+Cu\)
.0,05...0,05............0,05.....0,05.....
Thấy : \(\dfrac{1.n_{Fe}}{1.n_{CuSO_4}}=\dfrac{0,1}{0,05}=2>1\)
=> Sau phản ứng thu được 0,05 mol FeSO4, 0,05 mol Fe dư, 0,05 mol Cu .
Thấy Cu không phản ứng với HCl .
\(\Rightarrow m=m_{Cu}=3,2\left(g\right)\)
b, \(m_{ddY}=5,6+108-3,2-2,8=107,6\left(g\right)\)
\(\Rightarrow C\%_{FeSO_4}=\dfrac{0,05\left(56+96\right)}{107,6}.100\%\approx7,06\%\)
Bài 1:
\(a.n_{NaOH\left(tổng\right)}=0,05.1+0,2.0,2=0,09\left(mol\right)\\ V_{ddNaOH\left(tổng\right)}=50+200=250\left(ml\right)=0,25\left(l\right)\\ C_{MddNaOH\left(cuối\right)}=\dfrac{0,09}{0,25}=0,36\left(M\right)\\ b.n_{HCl}=0,5.0,02=0,01\left(mol\right)\\ n_{H_2SO_4}=0,08.0,2=0,016\left(mol\right)\\ V_{ddsau}=20+80=100\left(ml\right)=0,1\left(l\right)\\ C_{MddH_2SO_4}=\dfrac{0,016}{0,1}=0,16\left(M\right)\\ C_{MddHCl}=\dfrac{0,01}{0,1}=0,1\left(M\right)\)
Bài 2:
\(a.m_{H_2SO_4}=29,4.10\%=2,94\left(g\right)\\ b.n_{H_2SO_4}=\dfrac{2,94}{98}=0,03\left(mol\right)\\ n_{Fe}=\dfrac{0,56}{56}=0,01\left(mol\right)\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ Vì:\dfrac{0,01}{1}< \dfrac{0,03}{1}\Rightarrow H_2SO_4dư\\ n_{H_2SO_4\left(dư\right)}=0,03-0,01=0,02\left(mol\right)\\ m_{H_2SO_4\left(dư\right)}=0,02.98=1,96\left(g\right)\\ n_{H_2}=n_{Fe}=0,01\left(mol\right)\\ \Rightarrow V_{H_2\left(đktc\right)}=0,01.22,4=0,224\left(l\right)\)
a, \(n_{HNO_3}=0,3.1=0,3\left(mol\right)\)
\(n_{Ba\left(OH\right)_2}=0,1.1=0,1\left(mol\right)\)
PT: \(2HNO_3+Ba\left(OH\right)_2\rightarrow Ba\left(NO_3\right)_2+2H_2O\)
Xét tỉ lệ: \(\dfrac{0,3}{2}>\dfrac{0,1}{1}\), ta được HNO3 dư.
Theo PT: \(\left\{{}\begin{matrix}n_{Ba\left(NO_3\right)_2}=n_{Ba\left(OH\right)_2}=0,1\left(mol\right)\\n_{HNO_3\left(pư\right)}=2n_{Ba\left(OH\right)_2}=0,2\left(mol\right)\end{matrix}\right.\)
⇒ nHNO3 (dư) = 0,3 - 0,2 = 0,1 (mol)
\(\Rightarrow\left\{{}\begin{matrix}C_{M_{Ba\left(NO_3\right)_2}}=\dfrac{0,1}{0,3+0,1}=0,25\left(M\right)\\C_{M_{HNO_3\left(dư\right)}}=\dfrac{0,1}{0,3+0,1}=0,25\left(M\right)\end{matrix}\right.\)
b, Ta có: \(n_{Na_2CO_3}=0,25.0,5=0,125\left(mol\right)\)
PT: \(Na_2CO_3+2HNO_3\rightarrow2NaNO_3+CO_2+H_2O\)
______0,05______0,1_______________0,05 (mol)
⇒ VCO2 = 0,05.22,4 = 1,12 (l)
\(Na_2CO_3+Ba\left(NO_3\right)_2\rightarrow2NaNO_3+BaCO_{3\downarrow}\)
0,075________0,075_______________0,075 (mol)
⇒ mBaCO3 = 0,075.197 = 14,775 (g)
MgCl2+2AgNO3->Mg(NO3)2+2AgCl
0,04-----0,08-----------0,04----------0,08
n MgCl2=0,1 mol
n AgNO3=0,08 mol
=>Mgcl2 dư
=>m AgCl=0,08.143,5=11,48g
=>CMMg(NO)2=\(\dfrac{0,04}{0,2}\)=0,2M
=>CMMgcl2 dư=\(\dfrac{0,06}{0,2}\)=0,3M
\(n_{MgCl_2}=0,1\cdot1=0,1mol\)
\(n_{AgNO_3}=0,1\cdot0,8=0,08mol\)
\(MgCl_2+2AgNO_3\rightarrow2AgCl\downarrow+Mg\left(NO_3\right)_2\)
0,1 0,08 0 0
0,04 0,08 0,08 0,04
0,06 0 0,08 0,04
\(m_{\downarrow}=0,08\cdot143,5=11,48g\)
\(C_{M_{Mg\left(NO_3\right)_2}}=\dfrac{n_{Mg\left(NO_3\right)_2}}{V_X}=\dfrac{0,04}{0,2}=0,2M\)
gọi nMg=x và nAl = y
nHCl= 0,5 x 2= 1 mol
Mg + 2HCl → MgCl2 + H2x 2x x
2Al + 6HCl → 2AlCl3 + 3H2y 3y y
do dd sau pư trung hòa được với NaOH thu được dd x
→ HCl dư và chỉ có HCl tác dụng với NaOH
→ nHCl dư= 1 - 2x -3y mol
HCl + NaOH → H2O + NaCl 0,3mol ← 0,3 mol → 0,3 molta có hệ pt : \(\left\{{}\begin{matrix}24x+27y=7,5\\1-2x-3y=0,3\end{matrix}\right.\rightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)
→mMg = 0,2 x 24 = 4,8 g ; mAl= 0,1 x 27 = 2,7 g
Vddx = 0,5 + 0,3 = 0,8 lít
CM MgCl2=\(\dfrac{0,2}{0,8}\)=0,25 M
CM AlCl3 =\(\dfrac{0,1}{0,8}\)= 0,125 M
CM NaCl =\(\dfrac{0,3}{0,8}\)= 0,375 M
\(\text{1)}m_{KOH}=40.35\%=14\left(g\right)\\ \rightarrow n_{KOH}=\dfrac{14}{56}=0,25\left(mol\right)\\ PTHH:KOH+HCl\rightarrow KCl+H_2O\\ \text{Theo pthh}:n_{HCl}=n_{KOH}=0,25\left(mol\right)\\ \rightarrow V_{ddHCl}=0,25.0,5=0,125\left(l\right)\)
\(\text{2)}n_{Al}=\dfrac{4,05}{27}=0,15\left(mol\right)\\ n_{H_2SO_4}=200.14,7\%=29,4\left(g\right)\\ \rightarrow n_{H_2SO_4}=\dfrac{29,4}{98}=0,3\\ \text{PTHH}:2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\\ \text{LTL}:\dfrac{0,15}{2}< \dfrac{0,3}{3}\rightarrow H_2SO_4\text{ dư}\)
\(\text{Theo pthh}:\left\{{}\begin{matrix}n_{H_2SO_4\left(pư\right)}=\dfrac{3}{2}n_{Al}=\dfrac{3}{2}.0,15=0,225\left(mol\right)\\n_{H_2}=n_{H_2SO_4\left(pư\right)}=0,225\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Al}=\dfrac{1}{2}.0,15=0,075\left(mol\right)\end{matrix}\right.\\ \rightarrow m_{dd\left(\text{sau phản ứng}\right)}=200+4,05-0,3.2=203,45\left(g\right)\)
\(\rightarrow\left\{{}\begin{matrix}C\%_{H_2SO_4\text{ dư}}=\dfrac{\left(0,3-0,225\right).98}{203,45}=3,61\%\\C\%_{Al_2\left(SO_4\right)_3}=\dfrac{342.0,075}{203,45}=12,61\%\end{matrix}\right.\)
\(n_{Zn}=\dfrac{6.5}{65}=0.1\left(mol\right)\)
\(n_{H_2SO_4}=0.3\cdot1=0.3\left(mol\right)\)
\(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)
\(0.1........0.1...........0.1.......0.1\)
\(\Rightarrow H_2SO_4dư\)
\(n_{H_2SO_4\left(dư\right)}=0.3-0.1=0.2\left(mol\right)\)
\(n_{ZnSO_4}=n_{H_2}=0.1\left(mol\right)\)
\(C_{M_{ZnSO_4}}=\dfrac{0.1}{0.3}=0.33\left(M\right)\)
\(C_{M_{H_2SO_4\left(dư\right)}}=\dfrac{0.2}{0.3}=0.66\left(M\right)\)
\(a) Zn + H_2SO_4 \to ZnSO_4 + H_2\\ b) n_{Zn} = \dfrac{6,5}{65} = 0,1 < n_{H_2SO_4} =0,3 \to H_2SO_4\ dư\\ n_{H_2SO_4\ pư} = n_{ZnSO_4} = n_{Zn} = 0,1(mol)\\ n_{H_2SO_4\ dư} = 0,3 - 0,1 = 0,2(mol)\\ c) C_{M_{ZnSO_4}} = \dfrac{0,1}{0,3} = 0,33M\\ C_{M_{H_2SO_4}} = \dfrac{0,2}{0,3} = 0,67M\)
a, Gọi \(m_{NaCl\left(thêm\right)}=a\left(g\right)\)
\(m_{NaCl\left(bđ\right)}=5\%.100=5\left(g\right)\\ \Rightarrow C\%_{NaCl}=\dfrac{5+a}{100+a}.100\%=5,5\%\\ \Leftrightarrow a=0,53\left(g\right)\)
b, \(m_{NaCl}=58,5.5,5\%=3,2175\left(g\right)\\ n_{NaCl}=\dfrac{3,2175}{58,5}=0,055\left(mol\right)\)
PTHH: NaCl + AgNO3 ---> AgCl↓ + NaNO3
0,055-->0,055------>0,055---->0,055
\(m_{AgCl}=0,055.143,5=7,8925\left(g\right)\\ m_{ddY}=58,5+200-7,8925=250,6075\left(g\right)\\ \Rightarrow C\%_{NaNO_3}=\dfrac{0,055.85}{250,6075}.100\%=1,87\%\)
