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a, \(n_{Na_2O}=\dfrac{3,1}{62}=0,05\left(mol\right)\)
PTHH: Na2O + H2O → 2NaOH
Mol: 0,05 0,1
⇒ ddA (NaOH) làm quỳ tím đổi màu xanh
b, \(C_{M_{ddNaOH}}=\dfrac{0,1}{0,5}=0,2M\)
c, \(m_{ddA}=3,1+1.500=503,1\left(g\right)\)
d, \(C\%_{ddNaOH}=\dfrac{0,2.40.100\%}{503,1}=1,59\%\)
\(a.CaO+H_2O\rightarrow Ca\left(OH\right)_2\)
=> Hợp chất tạo thành làm quỳ tím hóa xanh.
b,c. Chưa đủ dữ kiện
Bài 1:
\(2Na+2H_2O\rightarrow2NaOH+H_2\\ n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\\ n_{Na}=n_{Na_2O}=0,2.2=0,4\left(mol\right)\\ a.m_{Na}=0,4.23=9,2\left(g\right)\\ b.C_{MddA}=\dfrac{0,4}{0,5}=0,8\left(M\right)\\ C\%_{ddA}=\dfrac{0,4.40}{500.1,2}.100\approx2,667\%\)
\(a,PTHH:Na_2O+H_2O\rightarrow2NaOH\\ \Rightarrow n_{NaOH}=2n_{Na_2O}=2\cdot\dfrac{37,2}{62}=0,6\cdot2=1,2\left(mol\right)\\ \Rightarrow C_{M_{NaOH}}=\dfrac{1,2}{0,5}=2,4M\\ b,PTHH:2NaOH+H_2SO_4\rightarrow Na_2SO_4+H_2O\\ \Rightarrow n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,6\left(mol\right)\\ \Rightarrow m_{H_2SO_4}=0,6\cdot98=58,8\left(g\right)\\ \Rightarrow m_{dd_{H_2SO_4}}=\dfrac{58,8\cdot100\%}{20\%}=294\left(g\right)\\ \Rightarrow V_{dd}=\dfrac{294}{1,14}\approx257,9\left(ml\right)\)
a, \(n_{K_2O}=\dfrac{4,7}{94}=0,05\left(mol\right)\)
PTHH: K2O + H2O → 2KOH
Mol: 0,05 0,1
b) \(C_{M_{ddKOH}}=\dfrac{0,1}{0,02}=5M\)
c)
PTHH: KOH + HCl → KCl + H2O
Mol: 0,1 0,1 0,1
\(m_{ddHCl}=\dfrac{0,1.36,5.100}{20}=18,25\left(g\right)\)
\(\Rightarrow V_{ddHCl}=\dfrac{18,25}{0,9125}=103,9\left(ml\right)=0,1039\left(l\right)\)
d) \(C_{M_{ddKCl}}=\dfrac{0,1}{0,02+0,1039}=0,8071M\)
\(n_{K_2O}=\dfrac{1,88}{94}=0,02(mol)\\ a,K_2O+H_2O\to 2KOH\\ b,n_{KOH}=0,04(mol)\\ \Rightarrow C_{M_{KOH}}=\dfrac{0,04}{0,5}=0,08M\\ c,n_{KOH}=0,04.50\%=0,02(mol)\\ KOH+HCl\to KCl+H_2O\\ \Rightarrow n_{HCl}=0,02(mol)\\ \Rightarrow m_{dd_{HCl}}=\dfrac{0,02.36,5}{7,3\%}=10(g)\)
a, \(n_{Na_2O}=\dfrac{7,75}{62}=0,125\left(mol\right)\)
PTHH: Na2O + H2O → 2NaOH
Mol: 0,125 0,25
b, \(C_{M_{ddNaOH}}=\dfrac{0,25}{0,25}=1M\)
c,
PTHH: 2NaOH + H2SO4 → Na2SO4 + 2H2O
Mol: 0,25 0,125
\(m_{ddH_2SO_4}=\dfrac{0,125.98.100}{20}=61,25\left(g\right)\)
\(\Rightarrow V_{ddH_2SO_4}=\dfrac{61,25}{1,14}=53,728\left(ml\right)\)
a. PTHH: \(Na_2O+H_2O\rightarrow2NaOH\)
\(NaOH:Bazo\rightarrow\)Quỳ hoá xanh
b. \(n_{Na_2O}=\frac{3,1}{62}=0,1mol\)
Theo phương trình \(n_{NaOH}=2n_{Na_2O}=0,1mol\)
\(500ml=0,5l\)
\(\rightarrow C_{M_{NaOH}}=\frac{0,1}{0,5}=0,2M\)
c. \(m_{ddH_2O}=1.500=500g\)
\(\rightarrow m_{ddA}=m_{ddNaOH}=m_{H_2O}+m_{Na_2O}\)
\(\rightarrow m_{ddNaOH}=500+3,1=503,1g\)
d. \(m_{NaOH}=0,1.40=4g\)
\(\rightarrow C\%_{NaOH}=\frac{4}{503,1}.100\%\approx0,795\%\)