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\(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\)
PTHH :
\(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
0,2 0,4 0,2 0,2
\(a,V_{H_2}=0,2.22,4=4,48\left(l\right)\)
\(b,m_{HCl}=0,4.36,5=14,6\left(g\right)\)
\(m_{ddHCl}=\dfrac{14,6.100}{10}=146\left(g\right)\)
\(c,m_{MgCl_2}=0,2.95=19\left(g\right)\)
\(m_{ddMgCl_2}=4,8+146-\left(0,2.2\right)=150,4\left(g\right)\)
\(C\%_{MgCl_2}=\dfrac{19}{150,4}.100\%\approx12,63\%\)
2.
\(n_K=\dfrac{7,8}{39}=0,2\left(mol\right)\)
\(2K+2H_2O\rightarrow2KOH+H_2\uparrow\)
0,2 0,2 0,1
\(m_{KOH}=0,2.56=11,2\left(g\right)\)
\(m_{ddKOH}=7,8+100-\left(0,1.2\right)=107,6\left(g\right)\)
\(C\%=\dfrac{11,2}{107,6}.100\%\approx10,4\%\)
\(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\\
pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\)
0,1 0,2 0,1 0,1
\(m_{HCl}=0,2.36,5=7,3\left(g\right)\\
V_{H_2}=0,1.22,4=2,24l\\
m_{\text{dd}}=6,5+200-\left(0,1.2\right)=206,3g\)
bài 2 :
\(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\\
pthh:Mg+2HCl\rightarrow MgCl_2+H_2\)
0,2 0,4 0,2 0,2
\(m_{HCl}=0,4.36,5=14,6g\\
V_{H_2}=0,2.22,4=4,48l\\
m\text{dd}=4,8+200-0,4=204,4g\\
C\%=\dfrac{0,2.136}{204,4}.100\%=13,3\%\)
\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\ PTHH:Zn+2HCl\rightarrow ZnCl_2+H_2\\ n_{H_2}=n_{ZnCl_2}=n_{Zn}=0,2\left(mol\right)\\ a,V_{H_2\left(Đktc\right)}=0,2.22,4=4,48\left(l\right)\\ b,m_{ZnCl_2}=136.0,2=27,2\left(g\right)\\ c,n_{HCl}=0,2.2=0,4\left(mol\right)\\ C\%_{ddHCl}=\dfrac{0,4.36,5}{200}.100\%=7,3\%\)
Coi như p/ứ vừa đủ
PTHH: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\uparrow\)
Ta có: \(n_{Zn}=\dfrac{19,5}{65}=0,3 \left(mol\right)=n_{H_2SO_4}=n_{ZnSO_4}=n_{H_2}\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{H_2SO_4}=\dfrac{0,3\cdot98}{200}=14,7\%\\V_{H_2}=0,3\cdot22,4=6,72\left(l\right)\\m_{H_2}=0,3\cdot2=0,6\left(g\right)\\m_{ZnSO_4}=0,3\cdot161=48,3\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{Zn}+m_{ddH_2SO_4}-m_{H_2}=218,9\left(g\right)\)
\(\Rightarrow C\%_{ZnSO_4}=\dfrac{48,3}{218,9}\cdot100\%\approx22,06\%\)
1:
a) \(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
PTHH: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\uparrow\)
______0,2------>0,2------------------->0,2_____(mol)
=> \(V_{H_2}=0,2.22,4=4,48\left(l\right)\)
b) \(V_{ddH_2SO_4}=\dfrac{0,2}{1}=0,2\left(l\right)\)
2:
a)
\(n_{HCl}=2.0,2=0,4\left(mol\right)\)
PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
______0,2<------0,4------------------>0,2______(mol)
=> \(m_{Mg}=0,2.24=4,8\left(g\right)\)
b) \(V_{H_2}=0,2.22,4=4,48\left(l\right)\)
2Al + 3H2SO4 -----> Al2(SO4)3 + 3H2
nAl = 7,1/27 = 71/270 ( mol)
=> nH2 = 71/180 ( mol)
=> VH2= 8,86 lit
=> m muối=71\540 .342=44,967g
\(n_{Al}=\dfrac{7,1}{27}=\dfrac{71}{270}\left(mol\right)\\
pthh:2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
\(\dfrac{71}{270}\) \(\dfrac{71}{540}\) \(\dfrac{71}{180}\)
\(V_{H_2}=\dfrac{71}{540}.22,4=3l\\
m_{Al_2\left(SO_4\right)_3}=342.\dfrac{71}{180}=134,9g\)
\(a,n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
PTHH: Zn + 2HCl ---> ZnCl2 + H2
0,2-->0,4--------->0,2--->0,2
=> V = 0,2.22,4 = 4,48 (l)
b, Thiếu V dd
\(c,m_{ZnCl_2}=0,2.136=27,2\left(g\right)\)
a) \(Mg+2HCl\rightarrow MgCl_2+H_2\)
\(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)
Theo PTHH ta có: \(n_{MgCl_2}=n_{Mg}=0,1\left(mol\right)\)
\(\Rightarrow m_{MgCl_2}=n_{MgCl_2}.M_{MgCl_2}=0,1.95=9,5\left(g\right)\)
b) Theo PTHH ta có: \(n_{H_2}=n_{Mg}=0,1\left(mol\right)\)
\(\Rightarrow V_{H_2}=n_{H_2}.22,4=0,1.22,4=2,24\left(l\right)\)
c) \(2H_2+O_2\rightarrow2H_2O\)
Theo PTHH: \(n_{H_2O}=\dfrac{0,1.2}{2}=0,1\left(mol\right)\)
\(\Rightarrow m_{H_2O}=n_{H_2O}.M_{H_2O}=0,1.18=1,8\left(g\right)\)
a)mMg= 2,4/24=0,1(mol) nMgCl2=0,1.1/1=0,1 (mol) mMgCl2= 0,1.95=9,5(g) b)nH2=0,1.1/1=0,1(mol) v=n.22,4=2,24(lít
cho 4 8g mg tác dụng vừa đủ với m gam dd hcl 14,6%
a. tính giá trị m và thể tích hidro
b C% muối thu đc
----------------------------------------------Giải-------------------------------------------------
a) \(n_{Mg}=\frac{48}{24}=2\left(mol\right)\)
PTHH: Mg + 2HCl -------> MgCl2 + H2
Theo PT : n HCl =2 n Mg =4(mol)
=> \(m_{ddHCl}=\frac{4.36,5}{14,6\%}=1000\left(g\right)\)
Theo PT : n H2 =n Mg =2 (mol)
=> V H2 =2 .22,4 =44,8 (l)
b) m dd sau phản ứng = 48 + 1000 - 2.2 = 1044 (g)
Theo PT : n MgCl2 =n Mg =2 (mol)
=> \(C\%_{MgCl_2}=\frac{2.95}{1044}.100=18,2\%\)
cho 13g zn tác dụng vừa đủ vs 200g dd H2SO4
a tính C% đ h2so4 đã dùng
b tính c% dd muối thu đc
----------------------------------------------Giải-------------------------------------------------
a) \(n_{Zn}=\frac{13}{65}=0,2\left(mol\right)\)
PTHH: Zn + H2SO4 ---------> ZnSO4 + H2
Theo PT : n H2SO4 = n Zn = 0,2 (mol )
=> \(C\%_{H_2SO_4}=\frac{0,2.98}{200}.100=9,8\%\)
b) Theo PT : n H2 = n Zn = 0,2 (mol )
m dd sau phản ứng = 13 + 200 - 0,2.2 = 212,6 (g)
Theo PT : n ZnSO4 = n Zn = 0,2 (mol )
=> \(C\%_{ZnSO_4}=\frac{0,2.161}{212,6}.100=15,15\%\)
dạ cô ơi bài 1 e ghi 4,8 thành 48 sai đề mong cô có thể giải lại giúp e bài đó.