Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
B1:
2NaOH+H2SO4\(\rightarrow\)Na2SO4+2H2O
nNaOH=\(\frac{4}{40}=0.1\)mol
=>nH2SO4=\(\frac{1}{2}\)nNaOH=0.05 mol
=>CM=\(\frac{n_{H2SO42}}{V}\)=\(\frac{0.05}{200}\)=2,5.10-4 (M)
B2:
Mg+\(\frac{1}{2}\)O2\(\underrightarrow{t^0}\)MgO (1)
MgO+2HCl\(\rightarrow\)MgCl2+H2O (2)
nMg(1)=\(\frac{0,36}{24}=0,015mol\)
=>nMgO(1)=0,015=nMgO(2)
nHCl(2)=2nMgO(2)=0,03mol
=>CM(HCl)=\(\frac{n_{HCl}}{V}=\frac{0,03}{100}=3.10^{-4}M\)
\(n_{NaOH}=0,8\left(mol\right)\)
\(PTHH:2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
\(n_{H2SO4}=\frac{1}{2}n_{NaOH}=0,4\left(mol\right)\)
\(\rightarrow m_{H2SO4}=0,4.98=39,2\left(g\right)\)
\(m_{dd_{H2SO4}}=392\left(g\right)\)
\(m_{dd_{spu}}=160+392=552\left(g\right)\)
\(\rightarrow C\%_{dd_X}=10,29\%\)
\(PTHH:H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O\)
Ban đầu 0,1________0,8
Phản ứng 0,1_________ 0,2 ______0,1
Dư ______ 0 ______ 0,6
\(m_{NaOH}=160.20\%=32g\)
\(n_{NaOH}=\frac{32}{23+17}=0,8\left(mol\right)\)
\(m_{H2SO4}=200.4,9\%=9,8\%\)
\(n_{H2SO4}=\frac{9,8}{32+2+16.4}=0,1\left(mol\right)\)
\(C\%_{Na2SO4}=\frac{0,1.\left(23.2+32+16.4\right)}{200+160}.100\%=3,94\%\)
\(C\%_{NaOH_{Du}}=\frac{0,6.\left(23+17\right)}{200}.100\%=65,16\%\)
\(n_{FeCl_3}=\dfrac{48,75}{162,5}=0,3(mol)\\ 3NaOH+FeCl_3\to Fe(OH)_3\downarrow+3NaCl\\ \Rightarrow n_{Fe(OH)_3}=0,3(mol);n_{NaOH}=n_{NaCl}=0,9(mol)\\ a,m_{Fe(OH)_3}=0,3.107=32,1(g)\\ b,m_{dd_{NaOH}}=\dfrac{0,9.40}{10\%}=360(g)\\ c,C\%_{NaCl}=\dfrac{0,9.58,5}{360+48,75-32,1}.100\%=13,98\%\\ \)
\(d,2Fe(OH)_3+3H_2SO_4\to Fe_2(SO_4)_3+6H_2O\\ \Rightarrow n_{H_2SO_4}=0,45(mol)\\ \Rightarrow m_{dd_{H_2SO_4}}=\dfrac{0,45.98}{20\%}=220,5(g)\\ \Rightarrow V_{dd_{H_2SO_4}}=\dfrac{220,5}{1,14}=193,42(ml)\)
Ta có: \(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
a. PTHH: \(Zn+H_2SO_4--->ZnSO_4+H_2\uparrow\left(1\right)\)
b. Theo PT(1): \(n_{Zn}=n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow m_{Zn}=65.0,3=19,5\left(g\right)\)
c. Theo PT(1): \(n_{H_2SO_4}=n_{Zn}=0,3\left(mol\right)\)
Đổi 300ml = 0,3 lít
\(\Rightarrow C_{M_{H_2SO_4}}=\dfrac{0,3}{0,3}=1M\)
d. PTHH: \(2NaOH+H_2SO_4--->Na_2SO_4+2H_2O\left(2\right)\)
Theo PT(2): \(n_{NaOH}=2.n_{H_2SO_4}=2.0,3=0,6\left(mol\right)\)
\(\Rightarrow m_{NaOH}=0,6.40=24\left(g\right)\)
\(\Rightarrow m_{dd_{NaOH}}=\dfrac{24.100\%}{20\%}=120\left(g\right)\)
PTHH : 2NaOH + CuSO4 → Cu(OH)2 + Na2SO4
\(m_{CuSO4}=\frac{C\%_{ddCuSO4}.m_{ddCuSO4}}{100\%}=\frac{20\%.160}{100\%}=32g\)
-> \(n_{CuSO4}=\frac{m_{CuSO4}}{M_{CuSO4}}=\frac{32}{64+32+16.4}=0,2mol\)
a, Theo PTHH : \(n_{NaOH}=2n_{CuSO4}=2.0,2=0,4mol\)
-> \(m_{NaOH}=n_{NaOH}.M_{NaOH}=0,4.40=16g\)
Mà \(m_{ddNaOH}=\frac{100\%.m_{NaOH}}{C\%}=\frac{100.16}{20}=80g\)
b, Theo PTHH :
\(n_{Cu\left(OH\right)2}=n_{CuSO4}=0,2mol\)
\(n_{Na2SO4}=n_{CuSO4}=0,2mol\)
=> \(m_{Cu\left(OH\right)2}=n_{Cu\left(OH\right)2}.M_{Cu\left(OH\right)2}=0,2.98=19,6g\)
\(m_{Na2SO4}=n_{Na2SO4}.M_{Na2SO4}=0,2.142=28,4g\)
- Aps dụng định luật bảo toàn khối lượng .
\(m_{ddNaOH}+m_{ddCuSO4}=m_{Cu\left(OH\right)2}+m_{Na2SO4}\)
=>\(m_{ddNa2SO4}=m_{ddNaOH}+m_{ddCuSO4}-m_{Cu\left(OH\right)2}\)
=>\(m_{ddNa2SO4}=160+80-19,6=220,4g\)
- Vì các dung dịch CuSO4 tác dụng vừa đủ với dung dịch NaOH nên sau phản ứng thu được duy nhất dung dịch có chất tan là Na2SO4
-> \(C\%_{ddNa2SO4}=\frac{m_{Na2SO4}}{m_{ddNa2SO4}}.100\%=\frac{28,4}{220,4}.100\%\approx12,88\%\)
Gọi CTHH của oxit KL là A2On.
PT: \(A_2O_n+nH_2SO_4\rightarrow A_2\left(SO_4\right)_n+nH_2O\)
Ta có: \(n_{A_2O_n}=\dfrac{4,8}{2M_A+16n}\left(mol\right)\)
Theo PT: \(n_{H_2SO_4}=n.n_{A_2O_n}=\dfrac{4,8n}{2M_A+16n}\left(mol\right)\)
\(\Rightarrow m_{H_2SO_4}=\dfrac{4,8n}{2M_A+16n}.98=\dfrac{470,4n}{2M_A+16n}\left(g\right)\)
\(\Rightarrow m_{ddH_2SO_4}=\dfrac{\dfrac{470,4n}{2M_A+16n}}{10\%}=\dfrac{4704n}{2M_A+16}\left(g\right)\)
⇒ m dd sau pư = \(4,8+\dfrac{4704n}{2M_A+16}\left(g\right)\)
Theo PT: \(n_{A_2\left(SO_4\right)_n}=n_{A_2O_n}=\dfrac{4,8}{2M_A+16n}\left(mol\right)\)
\(\Rightarrow C\%_{A_2\left(SO_4\right)_n}=\dfrac{\dfrac{4,8.\left(2M_A+96n\right)}{2M_A+16}}{4,8+\dfrac{4704n}{2M_A+16n}}.100\%=12,9\%\)
\(\Rightarrow M_A\approx18,65m\)
Với m = 3, MA = 56 (g/mol) là thỏa mãn.
→ A là Fe.
Ta có: \(n_{Fe_2O_3}=\dfrac{4,8}{160}=0,03\left(mol\right)\)
Theo PT: \(n_{Fe_2\left(SO_4\right)_3}=n_{Fe_2O_3}=0,03\left(mol\right)\)
Gọi CTHH của muối P là Fe2(SO4)3.nH2O.
Có: H = 80% ⇒ nP = 0,03.80% = 0,024 (mol)
\(\Rightarrow M_P=\dfrac{13,488}{0,024}=562\left(g/mol\right)\)
\(\Rightarrow400+18n=562\Rightarrow n=9\)
Vậy: CTHH của P là Fe2(SO4)3.9H2O
\(n_{NaOH}=\frac{160.20}{100.40}=0,8\left(mol\right)\\ PTHH:2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\\ m_{H_2SO_4}=\left(\frac{0,8}{2}\right).98=39,2\left(g\right)\\ m_{ddH_2SO_4}=\frac{39,2.100}{10}=392\left(g\right)\\ m_{ddspu}=160+392=552\left(g\right)\\ C\%_{ddX}=\frac{0,4.142}{552}.100\%=10,29\left(\%\right)\)