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CO2+2NaOH\(\rightarrow\)Na2CO3+H2O
CO2+NaOH\(\rightarrow\)NaHCO3
Khi tác dụng với BaCl2 và Ba(OH)2 được kết tủa khác nhau chứng tỏ phải có phản ứng 2
Để có cả hai phản ứng thì 1<\(\frac{nNaOH}{nCO2}\)<2
\(\rightarrow\)1<b/a<2
2/
A+ H2SO4 -------> ASO4+ H2
0.375......0.375..............0.375....0.375
nH2=0.375 mol
mddH2SO4=\(\dfrac{0.375\cdot98}{10\%}\) =367.5 g
MASO4.nH2O=\(\dfrac{104.25}{0.375}=278\)
<=> A+96 +18n=278
<=>A=182-18n( 11>n>0, nϵN)
Với n=7=> A là Fe(II)
=> CTHH: FeSO4.7H2O
Ta có: mdd=mA+mddH2SO4-mH2=21+367.5-0.375*2=387.75
Lại có mFeSO4=152*0.375=57 g
=>C%FeSO4=(57*100)/387.75=14.7%
Bài 7 : Theo đề bài ta có : \(\left\{{}\begin{matrix}nNa=\dfrac{m1}{23}mol\\nNa2O=\dfrac{m2}{62}mol\end{matrix}\right.\)
Ta có PTHH 1 :
2Na + 2H2O \(\rightarrow\) 2NaOH + H2
\(\dfrac{m1}{23}mol..........\dfrac{m1}{23}mol..\dfrac{1}{2}.\dfrac{m1}{23}mol\) = \(\dfrac{m1}{46}mol\)
=> mddNaOH = m1 + p - 2.\(\dfrac{m1}{46}=m1+p-\dfrac{m1}{23}\)
mct = mNaOH = 40.\(\dfrac{m1}{23}\) = \(\dfrac{40.m1}{23}\left(g\right)\)
=> a% = \(\dfrac{\dfrac{40m1}{23}}{m1+p-\dfrac{m1}{23}}.100\%=\dfrac{4000m1}{22m1+23p}\%\left(1\right)\)
Ta có PTHH 2 :
Na2O + H2O \(\rightarrow\) 2NaOH
\(\dfrac{m2}{62}mol.........2\dfrac{m2}{62}=\dfrac{m2}{31}mol\)
=> mddNaOH = \(m2+p\) (g)
mct = mNaOH = \(40.\dfrac{m2}{31}=\dfrac{40.m2}{31}\left(g\right)\)
=> a% = \(\dfrac{\dfrac{40m2}{31}}{m2+p}.100\%=\dfrac{4000m2}{31m2+31.p}\) % (2)
Ta có (1) = (2)
<=> \(\dfrac{4000m1}{22m1+23p}\) = \(\dfrac{4000m2}{31m2+31p}\)
<=> 4000m2 ( 22m1 + 23p ) = 4000m1( 31m2 + 31p )
Phần rút gọn dễ nên bạn tự rút gọn nha !
PTHH: \(Na_2CO_3+2CH_3COOH\rightarrow2CH_3COONa+H_2O+CO_2\uparrow\)
Tính theo sản phẩm
Ta có: \(\left\{{}\begin{matrix}\Sigma n_{CH_3COOH}=\dfrac{160\cdot15\%}{60}=0,4\left(mol\right)\\n_{CO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}n_{CH_3COOH\left(dư\right)}=0,2\left(mol\right)=n_{CH_3COONa}\\n_{Na_2CO_3}=0,1\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{Na_2CO_3}=0,1\cdot106=10,6\left(g\right)\\m_{CH_3COONa}=0,2\cdot82=16,4\left(g\right)\\m_{CH_3COOH\left(dư\right)}=0,2\cdot60=12\left(g\right)\\m_{CO_2}=0,1\cdot44=4,4\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{Na_2CO_3}+m_{ddAxit}-m_{CO_2}=166,2\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{CH_3COONa}=\dfrac{16,4}{166,2}\cdot100\%\approx9,87\%\\C\%_{CH_3COOH\left(dư\right)}=\dfrac{12}{166,2}\cdot100\%\approx7,22\%\end{matrix}\right.\)
Ta có: \(\left\{{}\begin{matrix}n_{CO_2}=0,1\left(mol\right)\\n_{NaOH}=0,5\cdot0,3=0,15\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) Tạo 2 muối
PTHH: \(CO_2+NaOH\rightarrow NaHCO_3\)
a_______a__________a (mol)
\(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)
b_______2b_________2b (mol)
Ta lập được HPT \(\left\{{}\begin{matrix}a+b=0,1\\a+2b=0,15\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,05\\b=0,05\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{NaHCO_3}=0,05\cdot84=4,2\left(g\right)\\m_{Na_2CO_3}=0,05\cdot106=5,3\left(g\right)\end{matrix}\right.\)
2NaOH + CO2 -> Na2CO3 + H2O (1)
NaOH +CO2 -> NaHCO3 (2)
Đặt nNa2Co3=a
nNaHCO3=b
nCO2=0,3(mol)
Ta có:
\(\left\{{}\begin{matrix}a+b=0,3\\106a+84b=29,6\end{matrix}\right.\)
=>a=0,2;b=0,1
=>\(\sum\)nNaOH=0,2.2+0,1=0,5(mol)
V=\(\dfrac{0,5}{2}=0,25\)(lít)
1.
2NaOH + CO2 -> Na2CO3 + H2O (1)
NaOH + CO2 -> NaHCO3 (2)
Na2CO3 + CaCl2 -> CaCO3 + 2NaCl (3)
Na2CO3 + Ca(OH)2 -> CaCO3 + 2NaOH (4)
2NaHCO3 + Ca(OH)2 -> Na2CO3 + CaCO3 + 2H2O (5)
nCaCO3(3)=0,1(mol)
nCaCO3(4;5)=0,2(mol)
=>nCaCO3(5)=0,2-0,1=0,1(mol)
Theo PTHH 3 và 5 ta có:
nNa2CO3=nCaCO3(3)=0,1(mol)
nNaHCO3=2nCaCO3(5)=0,2(mol)
Theo PTHH 1 và 2 ta có:
nNaHCO3=nCO2=nNaOH=0,2(mol)
nNa2CO3=nCO2=0,1(mol)
2nNa2CO3=nNaOH=0,2(mol)
=>\(\sum\)nCO2=0,2+0,1=0,3(mol)
\(\sum\)nNaOH=0,2+0,2=0,4(mol)
VCO2=0,3.22,4=6,72(lít)
CM dd NaOH=\(\dfrac{0,4}{0,2}=2M\)
Gọi nR = x thì nAl = 4/3 x
R + 2HCl -------> RCl2 + H2
x ------> 2x --------> 2x ------> x
2Al + 6HCl -------> 2AlCl3 + 3H2
4/3 x --> 4x ---------> 4/3 x -----> 2x
nHCl bđ = 0,5 * 2 = 1 mol
n H2 = x + 2x = 10,08 / 22,4 -----------> 3x = 0,45 ------> x = 0,15 mol
n HCl dư = 1 - (2x + 4x) = 1 - 6x = 1 - 6 * 0,15 = 0,1 mol
HCl + NaOH ----------> NaCl + H2O
0,1 -----------------------------> 0,1 mol
mmuối khan = mAlCl3 + mRCl2 + mNaCl = 46,8
--------> 4/3 * 0,15 * 133,5 + 0,15 * (R + 71) + 0,1 * 58,5 = 46,8
----------> R = 24 . Vậy R là Mg
mhh KL = 24 * 0,15 + 4/3 * 0,15 * 27 = 9 (g)
\(Fe\left(0,1\right)+H_2SO_4\left(0,1\right)\rightarrow FeSO_4\left(0,1\right)+H_2\left(0,1\right)\)\(\left(1\right)\)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
Theo PTHH: \(n_{Fe}=0,1\left(mol\right)\)
\(\Rightarrow a=56.0,1=5,6\left(g\right)\)
\(n_{H_2SO_4}\left(pư\right)=0,1\left(mol\right)\)
Dung dịch A: \(\left\{{}\begin{matrix}FeSO_4:0,1\left(mol\right)\\H_2SO_4\left(dư\right)\end{matrix}\right.\)
\(FeSO_4\left(0,1\right)+BaCl_2\rightarrow FeCl_2+BaSO_4\left(0,1\right)\)\(\left(2\right)\)
\(H_2SO_4\left(0,1\right)+BaCl_2\rightarrow2HCl+BaSO_4\left(0,1\right)\)\(\left(3\right)\)
\(n_{BaSO_4}=\dfrac{46,46}{233}=0,2\left(mol\right)\)
Theo (2) và (3) \(\Rightarrow n_{H_2SO_4}=0,1\left(mol\right)\)
\(\Rightarrow n_{H_2SO_4}\left(bđ\right)=0,1+0,1=0,2\left(mol\right)\)
\(\Rightarrow C_{M_{H_2SO_4}}\left(bđ\right)=\dfrac{0,2}{0,2}=1\left(M\right)\)
L???
la lit do