\(a) n_{CH_3COOH} = \dfrac{200.12\%}{60} = 0,4(mol)\\ 2CH_3COOH + CaCO_3 \to (CH_3COO)_2Ca + CO_2 + H_2O\\ n_{CaCO_3} = n_{CO_2} = \dfrac{1}{2}n_{CH_3COOH} = 0,2(mol)\\ \Rightarrow a = \dfrac{0,2.100}{100\%-20\%} =25(gam)\\ V_B = 0,2.22,4 = 4,48(lít)\\ b) m_{dd\ sau\ pư} = m_{CaCO_3} + m_{dd\ CH_3COOH} - m_{CO_2} = 0,2.100 + 200 - 0,2.2 = 219,6(gam)\\ C\%_{(CH_3COO)_2Ca} = \dfrac{0,2.158}{219,6}.100\% = 36\%\)

Bài 1:

\(PTHH:2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\\ Zn+H_2SO_4\rightarrow ZnSO_4+H_2\\ n_{NaOH}=\dfrac{6}{40}=0,15\left(mol\right)\\ \Rightarrow n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=\dfrac{1}{2}\cdot0,15=0,075\left(mol\right)\\ \Rightarrow m=m_{H_2SO_4}=0,075\cdot98=7,35\left(g\right)\\ n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\ \Rightarrow n_{H_2}=0,2\left(mol\right)\\ \Rightarrow V=V_{H_2}=0,2\cdot22,4=4,48\left(l\right)\)

Đề bài yêu cầu gì bạn nhỉ?

Câu 1 :

mNaCl = 5.85*100/100= 5.85 g

mH2SO4 = 100*49/100=49 g

mNaOH = 100*20/100=20 g

BaSO4 không tan trong nước nên không tính được

Câu 2 :

nNa = 2.3/23 = 0.1 mol

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

0.1___________0.1______0.05

mdd sau phản ứng = 2.3 + 100 - 0.1 = 102.2 g

mNaOH = 4g

C%NaOH = 4/102.2*100% = 3.91%

Câu 3 :

nCa = 0.05 mol

Ca + 2H2O --> Ca(OH)2 + 2H2

0.05____________0.05_____0.1

mdd = 100 + 2 - 0.2 = 101.8 g

mCa(OH)2 = 3.7 g

C%Ca(OH)2 = 3.63%

Câu 4 :

nH2 = 5*10^-5 mol

Ca + 2H2O --> Ca(OH)2 + H2

5*10^-5__________5*10^-5__5*10^-5

mCa = 0.002 g

mCa(OH)2 = 0.0037 g

mdd sau phản ứng = 100 g

C%Ca(OH)2 = 0.0037%

\(KOH + HCl \to KCl + H_2O n_{KOH\ pư} = n_{KCl} = n_{HCl} = a(mol)\\ n_{KOH\ dư} = 0,1 -a(mol)\\ \Rightarrow 74,5a + (0,1 -a).56 = 6,525\\ \Rightarrow a = 0,05\\ C_{M_{HCl}} = \dfrac{0,05}{0,1} = 0,5M\)

PTHH: \(Na_2O+H_2O\rightarrow2NaOH\)

            \(2NaOH+CuSO_4\rightarrow Na_2SO_4+Cu\left(OH\right)_2\downarrow\)

            \(Cu\left(OH\right)_2\xrightarrow[]{t^o}CuO+H_2O\)

a) Ta có: \(n_{NaOH}=2n_{Na_2O}=2\cdot\dfrac{6,2}{62}=0,2\left(mol\right)\) \(\Rightarrow C\%_{NaOH}=\dfrac{0,2\cdot40}{6,2+193,8}\cdot100\%=4\%\)

b) Ta có: \(\left\{{}\begin{matrix}n_{NaOH}=0,2\left(mol\right)\\n_{CuSO_4}=\dfrac{200\cdot16\%}{160}=0,2\left(mol\right)\end{matrix}\right.\)

Xét tỉ lệ: \(\dfrac{0,2}{2}< \dfrac{0,2}{1}\) \(\Rightarrow\) CuSO₄ còn dư, tính theo NaOH

\(\Rightarrow n_{Cu\left(OH\right)_2}=0,1\left(mol\right)=n_{CuO}\) \(\Rightarrow m_{CuO}=0,1\cdot80=8\left(g\right)\)

c) PTHH: \(CuO+2HCl\rightarrow CuCl_2+H_2O\)

Theo PTHH: \(n_{HCl}=2n_{CuO}=0,2\left(mol\right)\) \(\Rightarrow V_{ddHCl}=\dfrac{0,2}{2}=0,1\left(l\right)=100\left(ml\right)\)

a) PTHH: \(MgO+2HCl\rightarrow MgCl_2+H_2O\)

b) Ta có: \(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\) 

\(\Rightarrow\left\{{}\begin{matrix}n_{MgCl_2}=0,2\left(mol\right)\\n_{HCl}=0,4\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{MgCl_2}=0,2\cdot95=19\left(g\right)\\C\%_{HCl}=\dfrac{0,4\cdot36,5}{200}\cdot100\%=7,3\%\end{matrix}\right.\)

Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{MgO}+m_{ddHCl}=208\left(g\right)\)

\(\Rightarrow C\%_{MgCl_2}=\dfrac{19}{208}\cdot100\%\approx9,13\%\)

c) PTHH: \(MgCl_2+2NaOH\rightarrow2NaCl+Mg\left(OH\right)_2\downarrow\)

Ta có: \(\left\{{}\begin{matrix}n_{MgCl_2}=0,2\left(mol\right)\\n_{NaOH}=\dfrac{200\cdot4\%}{40}=0,2\left(mol\right)\end{matrix}\right.\)

Xét tỉ lệ: \(\dfrac{0,2}{1}>\dfrac{0,2}{2}\) \(\Rightarrow\) NaOH p/ứ hết, MgCl₂ còn dư

\(\Rightarrow\left\{{}\begin{matrix}n_{NaCl}=0,2\left(mol\right)\\n_{Mg\left(OH\right)_2}=0,1\left(mol\right)=n_{MgCl_2\left(dư\right)}\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{NaCl}=0,2\cdot58,5=11,7\left(g\right)\\m_{MgCl_2\left(dư\right)}=9,5\left(g\right)\\m_{Mg\left(OH\right)_2}=0,1\cdot58=5,8\left(g\right)\end{matrix}\right.\)

Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{ddA}+m_{ddNaOH}-m_{Mg\left(OH\right)_2}=402,2\left(g\right)\)

\(\Rightarrow\left\{{}\begin{matrix}C\%_{NaCl}=\dfrac{11,7}{402,2}\cdot100\%\approx2,91\%\\C\%_{MgCl_2\left(dư\right)}=\dfrac{9,5}{402,2}\cdot100\%\approx2,36\%\end{matrix}\right.\) 

Theo gt ta có: $n_{MgO}=0,2(mol)$

a, $MgO+2HCl\rightarrow MgCl_2+H_2O$

b, Ta có: $n_{HCl}=0,4(mol)\Rightarrow x=7,3$

Bảo toàn khối lượng ta có: $m_{ddA}=208(g)$

$\Rightarrow \%C_{MgCl_2}=9,13\%$

c, Ta có: $n_{NaOH}=0,2(mol)$

$\Rightarrow n_{Mg(OH)_2}=0,1(mol)$

Bảo toàn khối lượng ta có: $m_{ddB}=208+200-0,1.58=402,2(g)$

$\Rightarrow \%C_{MgCl_2}=2,36\%$

a)

$MgO + 2HCl \to MgCl_2  + H_2O$

b)

$n_{MgO} = \dfrac{8}{40} = 0,2(mol)$

$n_{HCl} = 2n_{MgO} = 0,4(mol)$

$C\%_{HCl} = \dfrac{0,4.36,5}{200}.100\% = 7,3\%$

(x = 7,3)

$m_{dd\ A} = 8 + 200 = 208(gam)$
$C\%_{MgCl_2} = \dfrac{0,2.95}{208}.100\% = 9,13\%$

nHCl=(200.14,6%)/100=0,8(mol)

nBa(OH)2=(17,1%.200)/100=0,2(mol)

PTHH: Ba(OH)2 +2 HCl -> BaCl2 + 2 H2O

Ta có: 0,8/2 > 0,2/1

=> HCl dư, Ba(OH)2 hết=> Tính theo nHCl

=> nBaCl2=nBa(OH)2=0,2(mol) => mBaCl2= 208.0,2= 41,6(g)

nHCl(dư)=0,8 - 0,2.2=0,4(mol) => mHCl(dư)=0,4.36,5=14,6(g)

mddsau= 200+200=400(g)

C%ddBaCl2=(41,6/400).100=10,4%

C%ddHCl(dư)= (14,6/400).100=3,65%

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