tính khối lượng riêng của 300g dd H2SO4 5% bt thể tích dd là 250ml . Sau đó tìm cM của dd
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![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
PTHH: \(H_2SO_4+2KOH\rightarrow K_2SO+2H_2O\)
Ta có: \(n_{H_2SO_4}=0,2\cdot1=0,2\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{KOH}=0,4\left(mol\right)\\n_{K_2SO_4}=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}V_{ddKOH}=\dfrac{\dfrac{0,4\cdot56}{6\%}}{1,048}\approx356,2\left(ml\right)\\C_{M_{K_2SO_4}}=\dfrac{0,2}{0,2+0,3562}\approx0,36\left(M\right)\end{matrix}\right.\)
\(n_{H_2SO_4}=1.0,2=0,2\left(mol\right)\\ H_2SO_4+2KOH\rightarrow K_2SO_4+2H_2O\\ 0,2.........0,4........0,2.......0,2\left(mol\right)\\ a.m_{ddKOH}=\dfrac{0,4.56.100}{6}=\dfrac{1120}{3}\left(g\right)\\ V_{ddKOH}=\dfrac{\dfrac{1120}{3}}{1,048}=\dfrac{140000}{393}\left(ml\right)\approx0,356\left(l\right)\)
\(b.C_{MddK_2SO_4}=\dfrac{0,2}{\dfrac{140000}{393}+0,2}\approx0,00056\left(M\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(n_{CO_2}=\dfrac{2,24}{22,4}=0,1mol\\ CO_2+Ba\left(OH\right)_2\rightarrow BaCO_3+H_2O\\ n_{BaCO_3}=n_{CO_2}=0,1mol\\ Ba\left(OH\right)_2+H_2SO_4\rightarrow BaSO_4+2H_2O\\ n_{H_2SO_4}=n_{Ba\left(OH\right)_2}=0,1mol\\ m_{ddH_2SO_4}=\dfrac{0,1.98}{20\%}\cdot100\%=49g\\ V_{ddH_2SO_4}=\dfrac{49}{1,14}=42,98ml\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a)
\(n_{Na_2O}=\dfrac{31}{62}=0,5\left(mol\right)\)
PTHH: Na2O + H2O --> 2NaOH
______0,5--------------->1
=> \(C_{M\left(NaOH\right)}=\dfrac{1}{0,5}=2M\)
b)
PTHH: H2SO4 + 2NaOH --> Na2SO4 + 2H2O
______0,5<---------1
=> mH2SO4 = 0,5.98 = 49(g)
=> \(m_{dd\left(H_2SO_4\right)}=\dfrac{49.100}{20}=245\left(g\right)\)
=> \(V_{dd\left(H_2SO_4\right)}=\dfrac{245}{1,14}=214,912\left(ml\right)\)
\(n_{Na_2O}=\dfrac{31}{62}=0,5(mol)\\ a,Na_2O+H_2O\to 2NaOH\\ \Rightarrow n_{NaOH}=1(mol)\\ \Rightarrow C_{M_{NaOH}}=\dfrac{1}{0,5}=2M\\ b,2NaOH+H_2SO_4\to Na_2SO_4+2H_2O\\ \Rightarrow n_{H_2SO_4}=0,5(mol)\\ \Rightarrow m_{dd_{H_2SO_4}}=\dfrac{0,5.98}{20\%}=245(g)\\ \Rightarrow V_{dd_{H_2SO_4}}=\dfrac{245}{1,14}=214,91(ml)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(n_{C_2H_5OH}=\dfrac{92}{46}=2\left(mol\right)\)
\(CM_{C_2H_5OH}=\dfrac{2}{0,25}=8M\)
\(C\%_{doruou}=\dfrac{92}{250.0,8}.100=46^o\)
![](https://rs.olm.vn/images/avt/0.png?1311)
BaO+H2O -> Ba(OH)2
0,02 0,02
a) CM = n/V = 0,02/0,02 = 1M
b) Ba(OH)2 + H2SO4 -> BaSO4 +2H2O
0,02 0,02
=> m = 0,392 g
D = m/V = 1,14
=> 0,392/V = 1,14 => V = 0,34l
![](https://rs.olm.vn/images/avt/0.png?1311)
a) nMg= 2,4/24=0,1(mol); nAl=5,4/27=0,2(mol)
PTHH: Mg + H2SO4 -> MgSO4 + H2
0,1__________0,1_____0,1____0,1(mol)
PTHH: 2Al + 3 H2SO4 -> Al2(SO4)3 +3 H2
0,2_________0,3_______0,1________0,3(mol)
nH2SO4(tổng)=nH2(tổng)=0,1+0,3=0,4(mol)
V(H2,đktc)=(0,1+0,3).22,4=8,96(l)
b) mH2SO4=39,2(g)
CMddH2SO4=0,3/0,1=3(M)
=> C%ddH2SO4= (CMddH2SO4 .M(H2SO4) ) /(10D)= (3.98)/(10.1,2)=24,5%
Chúc em học tốt!
![](https://rs.olm.vn/images/avt/0.png?1311)
a, \(Na_2O+H_2O\rightarrow2NaOH\)
\(n_{Na_2O}=\dfrac{15,5}{62}=0,25\left(mol\right)\)
\(n_{NaOH}=2n_{Na_2O}=0,5\left(mol\right)\)
\(\Rightarrow C_{M_{NaOH}}=\dfrac{0,5}{0,5}=1\left(M\right)\)
b, \(H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O\)
\(n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,25\left(mol\right)\)
\(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,25.98}{20\%}=122,5\left(g\right)\)
\(\Rightarrow V_{ddH_2SO_4}=\dfrac{122,5}{1,14}\approx107,46\left(ml\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) nZnO=16,2/81=0,2(mol)
PTHH: ZnO + H2SO4 -> ZnSO4+ H2
0,2______0,2_______0,2(mol)
b) \(C_{MddH2SO4}=\dfrac{D_{ddH2SO4}.C\%_{ddH2SO4}.10}{M_{H2SO4}}=\dfrac{1,25.4,9.10}{98}=0,625\left(M\right)\\ \rightarrow V_{ddH2SO4}=\dfrac{0,2}{0,625}=0,32\left(l\right)\)
c) Vddsau= VddH2SO4=0,32(l)
=> CMddZnSO4= (0,2/0,32)=0,625(M)
Số mol của kẽm
nZn = \(\dfrac{m_{Zn}}{M_{Zn}}=\dfrac{16,2}{65}=0,25\left(mol\right)\)
a) Pt : Zn + H2SO4 → ZnSO4 + H2\(|\)
1 1 1 1
0,25 0,25 0,25
b) Số mol của axit sunfuric
nH2SO4 = \(\dfrac{0,25.1}{1}=0,25\left(mol\right)\)
Khối lượng của axit sunfuric
mH2SO4 = nH2SO4 . MH2SO4
= 0,25 . 98
= 24,5 (g)
Khối lượng của dung dịch axit sunfuric
C0/0H2SO4 = \(\dfrac{m_{ct}.100}{m_{dd}}\Rightarrow m_{dd}=\dfrac{m_{ct}.100}{C}=\dfrac{24,5.100}{4,9}=500\)(g)
Thể tích của dung dịch axit sunfuric
D = \(\dfrac{m}{V}\Rightarrow V=\dfrac{m}{D}=\dfrac{500}{1,25}=400\left(ml\right)\)
c) Số mol của kẽm sunfat
nZnSO4 = \(\dfrac{0,25.1}{1}=0,25\left(mol\right)\)
400ml = 0,4l
Nồng độ mol của kẽm sunfat
CMZnSO4 = \(\dfrac{n}{V}=\dfrac{0,25}{0,4}=0,625\left(M\right)\)
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