Cho 23,2 gam Fe3O4 tác dụng với 250 ml dung dịch H2SO4 2M thu được 2
muối và nước.
a/ Tính khối lượng muối thu được.
b/ Tính nồng độ các chất thu được sau phản ứng.
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a)
$CuO + H_2SO_4 \to CuSO_4 + H_2O$
$n_{CuO} = \dfrac{8}{80} = 0,1 < n_{H_2SO_4} = 0,2.1 = 0,2$ nên $H_2SO_4$ dư
Theo PTHH : $n_{CuSO_4} = n_{CuO} = 0,1(mol)$
$m_{CuSO_4} = 0,1.160 = 16(gam)$
b)
$n_{H_2SO_4\ dư} = 0,2 - 0,1 = 0,1(mol)$
$C_{M_{H_2SO_4\ dư}} = \dfrac{0,1}{0,2} = 0,5M$
$C_{M_{CuSO_4}} = \dfrac{0,1}{0,2} = 0,5M$
nFeO= 0,1(mol)
nH2SO4= 0,2(mol)
a) PTHH: FeO + H2SO4 -> FeSO4 + H2O
Ta có: 0,1/1 < 0,2/1
=> H2SO4 dư, FeO hết, tính theo nFeO
=> nH2SO4(p.ứ)=nFeSO4=nFeO=0,1(mol)
=> nH2SO4(dư)=0,2 - 0,1=0,1(mol)
mFeSO4=0,1.152=15,2(g)
b) Vddsau=VddH2SO4=200(ml)=0,2(l)
=>CMddH2SO4(dư)=CMddFeSO4=0,1/0,2=0,5(M)
a)
$FeO + H_2SO_4 \to FeSO_4 + H_2O$
$n_{FeO} = \dfrac{7,2}{72} = 0,1 < n_{H_2SO_4} = 0,2.1 = 0,2$ nên $H_2SO_4$ dư
Theo PTHH : $n_{FeSO_4} = n_{H_2SO_4\ pư} = n_{FeO} = 0,1(mol)$
$m_{FeSO_4} = 0,1.152 = 15,2(gam)$
b)
$n_{H_2SO_4\ dư} = 0,2 - 0,1 = 0,1(mol)$
Suy ra :
$C_{M_{FeSO_4}} = C_{M_{H_2SO_4\ dư}} = \dfrac{0,1}{0,2} = 0,5M$
a) PTHH: \(Na_2O+H_2O\rightarrow2NaOH\)
Ta có: \(n_{NaOH}=2n_{Na_2O}=2\cdot\dfrac{6,2}{62}=0,2\left(mol\right)\) \(\Rightarrow C_{M_{NaOH}}=\dfrac{0,2}{0,4}=0,5\left(M\right)\)
b) PTHH: \(2NaOH+CuSO_4\rightarrow Cu\left(OH\right)_2\downarrow+Na_2SO_4\)
Ta có: \(\left\{{}\begin{matrix}n_{NaOH}=0,2\left(mol\right)\\n_{CuSO_4}=0,2\cdot2,5=0,5\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,2}{2}< \dfrac{0,5}{1}\) \(\Rightarrow\) CuSO4 còn dư
\(\Rightarrow\left\{{}\begin{matrix}n_{Cu\left(OH\right)_2}=0,1\left(mol\right)=n_{Na_2SO_4}\\n_{CuSO_4\left(dư\right)}=0,4\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{Cu\left(OH\right)_2}=0,1\cdot98=9,8\left(g\right)\\C_{M_{Na_2SO_4}}=\dfrac{0,1}{0,4+0,2}\approx0,17\left(M\right)\\C_{M_{CuSO_4\left(dư\right)}}=\dfrac{0,4}{0,6}\approx0,67\left(M\right)\end{matrix}\right.\)
Ta có: \(n_{Fe_3O_4}=\dfrac{2,32}{232}=0,01\left(mol\right)\)
a. PTHH: Fe3O4 + 4H2SO4 ---> FeSO4 + Fe2(SO4)3 + 4H2O
Theo PT: \(n_{H_2SO_4}=4.n_{Fe_3O_4}=4.0,01=0,04\left(mol\right)\)
=> \(m_{H_2SO_4}=0,04.98=3,92\left(g\right)\)
Theo đề, ta có: \(C_{\%_{H_2SO_4}}=\dfrac{3,92}{m_{dd_{H_2SO_4}}}.100\%=20\%\)
=> \(m_{dd_{H_2SO_4}}=19,6\left(g\right)\)
b. Ta có: \(m_{dd_{SauPỨ}}=2,32+19,6=21,92\left(g\right)\)
Theo PT: \(n_{FeSO_4}=n_{Fe_2\left(SO_4\right)_3}=n_{Fe_3O_4}=0,01\left(mol\right)\)
=> \(m_{FeSO_4}=0,01.152=1,52\left(g\right)\)
\(m_{Fe_2\left(SO_4\right)_3}=0,01.400=4\left(g\right)\)
=> \(m_{SauPỨ}=1,52+4=5,52\left(g\right)\)
=> \(C_{\%_{SauPỨ}}=\dfrac{5,52}{21,92}.100\%=25,18\%\)
n H2SO4=\(\dfrac{10\%.490}{2+32+16.4}=0,5mol\)
n Al2O3 =\(\dfrac{10,2}{27.2+16.3}=0,1mol\)
\(Al_2O_3+3H_2SO_4->Al_2\left(SO_4\right)_3+3H_2O\)
bđ 0,1............0,5
pư 0,1............0,3..................0,1
spu 0 ................0,2................0,1
=> sau pư gồm H2SO4 dư , Al2(S04)3 và H2O
m H2SO4 dư = \(0,2.\left(2+32+16.3\right)=19,6g\)
m Al2(SO4)3 = \(0,1\left(27.2+32.3+16.4.3\right)=34,2g\)
m dd = \(490+10,2=500,2g\)
% Al2(SO4)3 = \(\dfrac{34,2}{500,2}.100\sim6,84\%\)
% H2SO4 dư = \(\dfrac{19,6}{500,2}.100\sim3,92\%\)
a) \(n_{NaOH}=0,2.1=0,2\left(mol\right);n_{H_2SO_4}=0,15.2=0,3\left(mol\right)\)
PTHH: 2NaOH + H2SO4 → Na2SO4 + 2H2O
Mol: 0,2 0,1
Ta có: \(\dfrac{0,2}{2}< \dfrac{0,3}{1}\) ⇒ NaOH hết, H2SO4 dư
\(m_{Na_2SO_4}=0,1.142=14,2\left(g\right)\)
b) Vdd sau pứ = 0,2 + 0,15 = 0,35 (l)
\(C_{M_{ddNa_2SO_4}}=\dfrac{0,1}{0,35}=\dfrac{2}{7}\approx0,2857M\)
\(C_{M_{ddH_2SO_4dư}}=\dfrac{0,3-0,1}{0,35}=\dfrac{4}{7}\approx0,57M\)
Ta có: \(n_{H_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)
PT: \(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
a, \(n_{Al}=\dfrac{2}{3}n_{H_2}=\dfrac{1}{6}\left(mol\right)\Rightarrow m_{Al}=\dfrac{1}{6}.27=4,5\left(g\right)\)
b, \(n_{H_2SO_4}=n_{H_2}=0,25\left(mol\right)\Rightarrow C_{M_{H_2SO_4}}=\dfrac{0,25}{0,2}=1,25\left(M\right)\)
c, \(n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{3}n_{H_2}=\dfrac{1}{12}\left(mol\right)\)
\(\Rightarrow m_{Al_2\left(SO_4\right)_3}=\dfrac{1}{12}.342=28,5\left(g\right)\)
\(n_{FeSO_4}=0,5.0,3=0,15\left(mol\right)\\ n_{Mn}=\dfrac{5,5}{55}=0,1\left(mol\right)\\ Mn+FeSO_4\rightarrow MnSO_4+Fe\\ Vì:\dfrac{0,15}{1}< \dfrac{0,1}{1}\Rightarrow FeSO_4dư\\ n_{MnSO_4}=n_{Mn}=0,1\left(mol\right)\\ n_{FeSO_4\left(dư\right)}=0,15-0,1=0,05\left(mol\right)\\ V_{ddsau}=V_{ddFeSO_4}=0,3\left(l\right)\\ C_{MddFeSO_4\left(dư\right)}=\dfrac{0,05}{0,3}=\dfrac{1}{6}\left(M\right)\\ C_{MddMnSO_4}=\dfrac{0,1}{0,3}=\dfrac{1}{3}\left(M\right)\)
C% thì em bổ sung KLR của dd nhé!
250ml=0,25l
\(MgO+2HCl\rightarrow MgCl_2+H_2O\)
0.2.........0.4..........0,2............0,2 (mol)
a)
\(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
\(m_{MgCl_2}=0,2.95=19\left(g\right)\)
b)
\(C_{M_{HCl}}=\dfrac{0,4}{0,25}=1,6\left(M\right)\)
a/ \(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
PTHH: MgO + 2HCl → MgCl2 + H2O
Mol: 0,2 0,4 0,2
\(m_{MgCl_2}=0,2.95=19\left(g\right)\)
b/ \(C_{M_{ddHCl}}=\dfrac{0,4}{0,25}=1,6M\)
nFe3O4= 23,2/232=0,1(mol)
nH2SO4=2.0,25=0,5(mol)
a) PTHH: Fe3O4 + 4 H2SO4 -> Fe2(SO4)3 + FeSO4 + 4 H2O
Ta có: 0,1/1 < 0,5/4
=> H2SO4 dư, Fe3O4 hết, tính theo Fe3O4
nFe2(SO4)3=nFeSO4=nFe3O4=0,1(mol)
=> mFe2(SO4)3=0,1.400=40(g)
mFeSO4=0,1.152=15,2(g)
b) nH2SO4(dư) = 0,5- 0,1.4=0,1(mol)
Vddsau=VddH2SO4=0,25(l)
=> CMddH2SO4(dư)=CMddFe2(SO4)3=CMddFeSO4=0,1/0,25=0,4(M)