Câu 3: Cho 6,5 gam Zn tác dụng hết với dd H2SO4 25%
a. Viết PTHH của phản ứng
b. Tính thể tích khí thoát ra ở đktc?
c. Tính nồng độ phần trăm (%) dung dịch thu được sau phản ứng?
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Câu 3.
a, \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
PTHH: Zn + H2SO4 → ZnSO4 + H2
Mol: 0,1 0,1 0,1 0,1
b,\(V_{H_2}=0,1.22,4=2,24\left(l\right)\)
c,\(m_{ZnSO_4}=0,1.161=16,1\left(g\right)\)
\(m_{ddsaupư}=6,5+\dfrac{0,1.98.100}{25}-0,1.2=45,5\left(g\right)\)
\(\Rightarrow C\%_{ddZnSO_4}=\dfrac{16,1.100\%}{45,5}=35,4\%\)
n Zn= 19,5/65=0,3 (mol).
PTPƯ: Zn(0.3) + HCl(0.6) ----> ZnCl2(0.3) + H2(0,3)
mHCl=0,6.36.5=21.9(g)
a) C%HCl= 21.9/300.100%=7,3%
b) VH2=0,3.22,4=6,72(lít)
c) mH2=0,3.2=0,6(g)
mZnCl2=0,3.136=40,8(g)
mddZnCl2 =(19,5+300)-0,6=318,9(g)
C%=mZnCl2/mddZnCl2.100= 40,8/318,9.100=12,793%
Fe+H2SO4->FeSO4+H2
0,15---0,15-----0,15---0,15 mol
n Fe=8,4\56=0,15 mol
=>VH2=0,15.22,4=3,36l
=>m H2SO4=0,15.98=14,7g
=>C% H2SO4=14,7\245 .100=6%
=>m dd muối=8,4+245-0,15.2=253,1g
=>C% muối =0,15.152\253,1 .100=9%
`a)PTHH:`
`Zn + 2HCl -> ZnCl_2 + H_2`
`0,02` `0,02` `0,02` `(mol)`
`n_[Zn]=[1,3]/65=0,02(mol)`
`b)V_[H_2]=0,02.22,4=0,448(l)`
`c)C%_[ZnCl_2]=[0,02.136]/[1,3+50-0,02.2].100~~5,31%`
\(n_{Zn}=\dfrac{1,3}{65}=0,02\left(mol\right)\)
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
0,02 0,04 0,02 0,02 ( mol )
\(V_{H_2}=0,02.22,4=0,448\left(l\right)\)
\(C\%_{ZnCl_2}=\dfrac{0,02.136}{1,3+50-0,02.2}.100=5,3\%\)
Bài 4 :
\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\)
a) Pt : \(Zn+2HCl\rightarrow ZnCl_2+H_2|\)
1 2 1 1
0,2 0,4 0,2 0,2
b) \(n_{H2}=\dfrac{0,2.1}{1}=0,2\left(mol\right)\)
\(V_{H2\left(dktc\right)}=0,2.22,4=4,48\left(l\right)\)
c) \(n_{HCl}=\dfrac{0,2.2}{1}=0,4\left(mol\right)\)
⇒ \(m_{HCl}=0,4.36,5=14,6\left(g\right)\)
\(C_{ddHCl}=\dfrac{14,6.100}{100}=14,6\)0/0
d) \(n_{ZnCl2}=\dfrac{0,2.1}{1}=0,2\left(mol\right)\)
⇒ \(m_{ZnCl2}=0,2.136=27,2\left(g\right)\)
\(m_{ddspu}=13+100-\left(0,2.2\right)=112,6\left(g\right)\)
\(C_{ZnCl2}=\dfrac{27,2.100}{112,6}=24,16\)0/0
Chúc bạn học tốt
Bài 3 :
\(n_{Mg}=\dfrac{12}{24}=0,5\left(mol\right)\)
a) Pt : \(Mg+H_2SO_4\rightarrow MgSO_4+H_2|\)
1 1 1 1
0,5 0,5 0,5 0,5
b) \(n_{H2}=\dfrac{0,5.1}{1}=0,5\left(mol\right)\)
\(V_{H2\left(dktc\right)}=0,5.22,4=11,2\left(l\right)\)
c) \(n_{H2SO4}=\dfrac{0,5.1}{1}=0,5\left(mol\right)\)
⇒ \(m_{H2SO4}=0,5.98=49\left(g\right)\)
\(C_{ddH2SO4}=\dfrac{49.100}{200}=24,5\)0/0
d) \(n_{MgSO4}=\dfrac{0,5.1}{1}=0,5\left(mol\right)\)
⇒ \(m_{MgSO4}=0,5.120=60\left(g\right)\)
\(m_{ddspu}=12+200-\left(0,5.2\right)=211\left(g\right)\)
\(C_{MgSO4}=\dfrac{60.100}{211}=28,44\)0/0
Chúc bạn học tốt
a) \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
\(m_{H_2SO_4}=147.10\%=14,7\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{14,7}{98}=0,15\left(mol\right)\)
PTHH: Zn + H2SO4 → ZnSO4 + H2
Mol: 0,1 0,1 0,1 0,1
Ta có: \(\dfrac{0,1}{1}< \dfrac{0,15}{1}\) ⇒ Zn hết, H2SO4 dư
b) \(V_{H_2}=0,1.22,4=2,24\left(l\right)\)
c) mdd sau pứ = 6,5 + 147 - 0,1.2 = 153,3 (g)
\(C\%_{ddZnSO_4}=\dfrac{0,1.161.100\%}{153,3}=10,502\%\)
\(C\%_{ddH_2SO_4dư}=\dfrac{\left(0,15-0,1\right).98.100\%}{153,3}=3,196\%\)
Câu 1:
a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, \(n_{Zn}=\dfrac{16,25}{65}=0,25\left(mol\right)\)
\(n_{H_2}=n_{Zn}=0,25\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,25.24,79=6,1975\left(l\right)\)
c, \(n_{HCl}=2n_{Zn}=0,5\left(mol\right)\)
\(\Rightarrow m_{HCl}=0,5.36,5=18,25\left(g\right)\)
\(\Rightarrow m_{ddHCl}=\dfrac{18,25}{10\%}=182,5\left(g\right)\)
d, \(n_{ZnCl_2}=n_{Zn}=0,25\left(mol\right)\)
\(\Rightarrow C\%_{ZnCl_2}=\dfrac{0,25.136}{16,25+182,5-0,25.2}.100\%\approx17,15\%\)
Câu 2:
a, \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
c, \(n_{NaOH}=\dfrac{40}{40}=1\left(mol\right)\)
Theo PT: \(n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,5\left(mol\right)\)
\(\Rightarrow V_{H_2SO_4}=\dfrac{0,5}{2}=0,25\left(l\right)\)
d, \(n_{Na_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,5\left(mol\right)\)
\(\Rightarrow C_{M_{Na_2SO_4}}=\dfrac{0,5}{0,25}=2\left(M\right)\)
a, \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(n_{H_2}=\dfrac{7,437}{24,79}=0,3\left(mol\right)\)
Theo PT: \(n_{Fe}=n_{H_2}=0,3\left(mol\right)\Rightarrow m_{Fe}=0,3.56=16,8\left(g\right)\)
b, \(n_{H_2SO_4}=n_{H_2}=0,3\left(mol\right)\Rightarrow C\%_{H_2SO_4}=\dfrac{0,3.98}{120}.100\%=24,5\%\)
c, m dd sau pư = 16,8 + 120 - 0,3.2 = 136,2 (g)
d, \(n_{FeSO_4}=n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow C\%_{FeSO_4}=\dfrac{0,3.152}{136,2}.100\%\approx33,48\%\)
\(n_{Zn}=\dfrac{8,125}{65}=0,125\left(mol\right)\\ m_{HCl}=\dfrac{100.18,25}{100}=18,25\left(g\right)\\
n_{HCl}=\dfrac{18,25}{36,5}=0,5\\ pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
0,125 0,125 (mol )
\(\Rightarrow V_{H_2}=0,125.22,4=2,8\left(l\right)\\
\)
\(C\%=\dfrac{8,125}{8,125+18,25}.100\%=30,8\%\)
Bài 18:
Ta có: \(n_{Zn}=\dfrac{8,125}{65}=0,125\left(mol\right)\)
\(m_{HCl}=100.18,25\%=18,25\left(g\right)\Rightarrow n_{HCl}=\dfrac{18,25}{36,5}=0,5\left(mol\right)\)
a, PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, Xét tỉ lệ: \(\dfrac{0,125}{1}< \dfrac{0,5}{2}\), ta được HCl dư.
Theo PT: \(n_{H_2}=n_{Zn}=0,125\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,125.22,4=2,8\left(g\right)\)
\(m_{H_2}=0,125.2=0,25\left(g\right)\)
c, Theo PT: \(\left\{{}\begin{matrix}n_{ZnCl_2}=n_{Zn}=0,125\left(mol\right)\\n_{HCl\left(pư\right)}=2n_{Zn}=0,25\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow n_{HCl\left(dư\right)}=0,25\left(mol\right)\)
Có: m dd sau pư = 8,125 + 100 - 0,25 = 107,875 (g)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{ZnCl_2}=\dfrac{0,125.136}{107,875}.100\%\approx15,76\%\\C\%_{HCl\left(dư\right)}=\dfrac{0,25.36,5}{107,875}.100\%\approx8,46\%\end{matrix}\right.\)
Bạn tham khảo nhé!
Ta có: \(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
a. PTHH: Zn + H2SO4 ---> ZnSO4 + H2
b. Theo PT: \(n_{H_2}=n_{Zn}=0,1\left(mol\right)\)
=> \(V_{H_2}=0,1.22,4=2,24\left(lít\right)\)
c. Theo PT: \(n_{H_2SO_4}=n_{Zn}=0,1\left(mol\right)\)
=> \(m_{H_2SO_4}=0,1.98=9,8\left(g\right)\)
Ta có: \(C_{M_{H_2SO_4}}=\dfrac{9,8}{m_{dd_{H_2SO_4}}}.100\%=25\%\)
=> \(m_{dd_{H_2SO_4}}=39,2\left(g\right)\)
Ta có: \(m_{H_2}=0,1.2=0,2\left(g\right)\)
=> \(m_{dd_{ZnSO_4}}=6,5+39,2-0,2=45,5\left(g\right)\)
Theo PT: \(n_{ZnSO_4}=n_{Zn}=0,1\left(mol\right)\)
=> \(m_{ZnSO_4}=0,1.161=16,1\left(g\right)\)
=> \(C_{\%_{ZnSO_4}}=\dfrac{16,1}{45,5}.100\%=35,4\%\)