BaO + H2O -> Ba(OH)2

0.01                   0.01

nBaO=\(\dfrac{1.53}{137+16}=0.01mol\)

C%Ba(OH)2=\(\dfrac{0.01\times\left(137+16\times2+2\right)\times100}{1.53+4.5}=28.36\%\)

a) - Dung dịch A chứa chất tan NaOH

mddNaOH= 200(g)

=> C%ddNaOH= (4/200).100=2%

b) Dung dịch A là gì?

nNa=4,6/23=0,2(mol)

PTHH: Na + H2O -> NaOH + 1/2 H2

0,2_______________0,2____0,1(mol)

mddNaOH=4,6+100-0,1.2=104,4(g)

mNaOH=0,2.40=8(g)

=>C%ddNaOH= (8/104,4).100=7,663% 

=> Chọn B (gần nhất)

\(n_K=\frac{5,85}{15}=0,15(mol)\\ K+H_2O \to KOH +\frac{1}{2}H_2\\ n_{KOH}=n_K=0,15(mol)\\ n_{H_2}=\frac{1}{2}.n_K=\frac{1}{2}.0,15=0,075(mol)\\ m_{dd}=5,85+100-(0,075.2)=105,7(g)\\ C\%=\frac{0,15.56}{105,7}.100=7,95\%\)

a)

$BaO + H_2O \to Ba(OH)_2$
$n_{Ba(OH)_2} = n_{BaO} = \dfrac{30,6}{153} = 0,2(mol)$
$C_{M_{Ba(OH)_2}} = \dfrac{0,2}{0,2} = 1M$

b)

$Ba(OH)_2 + 2HCl \to BaCl_2 + 2H_2O$
$n_{HCl} = 2n_{Ba(OH)_2} = 0,4(mol)$
$V_{dd\ HCl} = \dfrac{0,4}{0,5} = 0,8(lít)$

a) PTHH: \(SO_3+H_2O\rightarrow H_2SO_4\)

Ta có: \(n_{SO_3}=\dfrac{24}{80}=0,3\left(mol\right)=n_{H_2SO_4}\) \(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,3\cdot98}{20\%}=147\left(g\right)\)

\(\Rightarrow V_{ddH_2SO_4}=\dfrac{147}{1,14}\approx128,95\left(ml\right)\)

b) PTHH: \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)

Theo PTHH: \(n_{Fe}=n_{H_2SO_4}=n_{H_2}=0,3\left(mol\right)=n_{FeSO_4}\)

\(\Rightarrow\left\{{}\begin{matrix}m_{Fe}=0,3\cdot56=16,8\left(g\right)\\V_{H_2}=0,3\cdot24,76=7,428\left(l\right)\\m_{FeSO_4}=0,3\cdot152=45,6\left(g\right)\\m_{H_2}=0,3\cdot2=0,6\left(g\right)\end{matrix}\right.\)

Mặt khác: \(m_{dd}=m_{Fe}+m_{ddH_2SO_4}-m_{H_2}=163,2\left(g\right)\)

\(\Rightarrow C\%_{FeSO_4}=\dfrac{45,6}{163,2}\cdot100\%\approx27,94\%\)

\(K+H_2O\rightarrow KOH+\dfrac{1}{2}H_2\)

\(n_K=2n_{H_2}=0,2\left(mol\right)\Rightarrow m_K=7,8\left(g\right)\)

=> \(m_{K_2O}=17,2-7,8=9,4\Rightarrow n_{K_2O}=0,1\left(mol\right)\)

\(K_2O+H_2O\rightarrow2KOH\)

\(\Sigma n_{KOH}=0,2+0,1.2=0,4\left(mol\right)\)

\(m_{ddsaupu}=17,2+600-0,1.2=617\left(g\right)\)

=> \(C\%_{KOH}=\dfrac{0,4.56}{712}.100=3,15\%\)

${H2O}$

\(n_{HCl}=\dfrac{44,8}{22,4}=2\)

\(\Rightarrow m_{HCl}=2.36,5=73g\)

=> \(C\%_{HCl}=\dfrac{73}{73+327}\times100\%=18,25\%\)

b. 

\(n_{HCl}=\dfrac{250.18,25\%}{36,5}=1,25mol\)

\(n_{CaCO_3}=\dfrac{50}{100}=0,5mol\)

\(CaCO_3+2HCl\rightarrow CaCl_2+CO_2+H_2O\)

\(n_{CaCl_2}=n_{CO_2}=0,5mol\)

\(n_{HClpu}=0,5.2=1mol\)

\(\Rightarrow n_{HCldu}=1,25-1=0,25\)

\(\Rightarrow m_{ddpu}=50+250-0,5.44=278g\)

\(C\%_{HCl}=\dfrac{0,25.36,5}{278}.100\%=3,28\%\)

\(C\%_{CaCl_2}=\dfrac{0,5.111}{278}.100\%=19,96\%\)

\(CaO+H_2O->Ca\left(OH\right)_2\)

0,2..........................0,2

n CaO = \(\dfrac{11,2}{40+16}=0,2mol\)

m Ca(OH)2 = \(0,2.\left(40+16.2+1.2\right)=14,8g\)

C% Ca(OH)2 = \(\dfrac{14,8}{500}.100=2,96\%\)

Cảm ơn bạn