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bài1
ta có dA/H2=22 →MA=22MH2=22 \(\times\) 2 =44
nA=\(\frac{5,6}{22,4}\)=0,25
\(\Rightarrow\)mA=M\(\times\)n=11 g
MA=dA/\(H_2\)×M\(H_2\)=22×(1×2)=44g/mol
nA=VA÷22,4=5,6÷22,4=0,25mol
mA=nA×MA=0,25×44=11g
CaCO3 có PTK =100g/mol
=> %Ca=\(\frac{40}{100}.100=40\%\)
%C=12:100.100=12%
%O=3.16:100.100=48%
H2SO4 có PTK =98
=> %H=2.1:98.100=2%
%S=32:98.100=32,7%
=> %O=100-2-32,7=65,3%
Fe2O3 có PTK =160
=> %Fe=56.2:160.100=70%
=> %O=100-70=30%
Mg(OH)2 có PTK: 58g/mol
=> %Mg=24:56.100=42,9%
%H=1.2:56.100=3,6%
=> %O=100-42,9-3,6=56,5%
a) \(M_{Ca\left(OH\right)_2}=40+\left(16+1\right).2=74\left(DvC\right)\)
\(\%Ca=\dfrac{40.1}{74}.100\%=54\%\)
\(\%O=\dfrac{16.2}{74}.100\%=43\%\)
\(\%H=100\%-54\%-43\%=3\%\)
a) \(\left\{{}\begin{matrix}\%m_{Ca}=\dfrac{40.1}{74}.100\%=54,054\%\\\%m_O=\dfrac{16.2}{74}.100\%=43,243\%\\\%m_H=\dfrac{2.1}{74}.100\%=2,703\%\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}\%m_{Ba}=\dfrac{137.1}{208}.100\%=65,865\%\\\%Cl=\dfrac{35,5.2}{208}.100\%=34,135\%\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}\%m_K=\dfrac{39.1}{56}.100\%=69,643\%\\\%m_O=\dfrac{16.1}{56}.100\%=28,571\%\\\%m_H=\dfrac{1.1}{56}.100\%=1,786\%\end{matrix}\right.\)
d) \(\left\{{}\begin{matrix}\%m_{Al}=\dfrac{27.2}{102}.100\%=52,94\%\\\%m_O=\dfrac{16.3}{102}.100\%=47,06\%\end{matrix}\right.\)
e) \(\left\{{}\begin{matrix}\%m_{Na}=\dfrac{23.2}{106}.100\%=43,396\%\\\%m_C=\dfrac{12}{106}.100\%=11,321\%\\\%m_O=\dfrac{16.3}{106}.100\%=45,283\%\end{matrix}\right.\)
g) \(\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{56.1}{72}.100\%=77,78\%\\\%m_O=\dfrac{16.1}{72}.100\%=22,22\%\end{matrix}\right.\)
h) \(\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{65.1}{161}.100\%=40,373\%\\\%m_S=\dfrac{32.1}{161}.100\%=19,876\%\\\%m_O=\dfrac{16.4}{161}.100\%=39,751\%\end{matrix}\right.\)
i) \(\left\{{}\begin{matrix}\%m_{Hg}=\dfrac{201.1}{217}.100\%=92,627\%\\\%m_O=\dfrac{16}{217}.100\%=7,373\%\end{matrix}\right.\)
k) \(\%m_{Na}=\dfrac{23.1}{85}.100\%=27,06\%;\%m_N=\dfrac{14.1}{85}.100\%=16,47\%\%;\%m_O=\dfrac{16.3}{85}.100\%=56,47\%\)
câu 1:
\(PTK\) của \(H_2SO_4=2.1+1.32+4.16=98\left(đvC\right)\)
\(PTK\) của \(Ba\left(OH\right)_2=1.137+\left(1.16+1.1\right).2=171\left(đvC\right)\)
\(PTK\) của \(Al_2\left(SO_4\right)_3\)\(=2.27+\left(1.32+4.16\right).3=342\left(đvC\right)\)
\(PTK\) của \(Fe_3O_4=3.56+4.16=232\left(đvC\right)\)
câu 1: Al2O3 đúng còn lại là sai, sửa :AlCl3, Al2NO3, Al2(SO4)3, Al(OH)3,Al3(PO4)3
Câu 4: a) H2SO4= 2+32+16.4=200đvc
b)HCl=1+35,5=36,5đvc
c)NaOH=23+16+1=40đvc
Câu 5:a) 4Al+3O2 ---t*---->2Al2O3
b) 2P2+5O2---t*---->2P2O5
c)CH4+2O2---t*--->CO2+2H2O
d)Fe+S--->FeS
bạn tham khảo thử coi s chứ gv dạy hóa bạn như thế nào thì mk hk bt đc,mk làm theo cách của mk ak
Câu 2:
-Gọi công thức NaxCyOz
x:y+z=\(\dfrac{\%Na}{23}:\dfrac{\%C}{12}:\dfrac{\%O}{16}=\dfrac{43,4}{23}:\dfrac{11,3}{12}:\dfrac{45,3}{16}\approx2:1:3\)
-CTHH: Na2CO3
gọi công thức hợp chất A là CuxSyOz
ta có :x:y:z= \(\frac{40}{64}:\frac{20}{32}:\frac{40}{16}\)=1:1:4
=> công thức a là CuSO4
Câu 6:
a) Ta có: m\(_{ct}\)= 50(g)
C%\(_{dddường}\)= 25%
=> m\(_{dd}\)=\(\frac{50.100\%}{25\%}\)= 200(g)
b) m\(_{nước}\)= 200-50 = 150(g)
Câu 7
Fe + H\(_2\)SO\(_4\) \(\rightarrow\) FeSO\(_4\) + H\(_2\)
Mol: 0,25 : 0,25 \(\rightarrow\) 0,25: 0,25
Ta có: m\(_{Fe}\)= 22,4(g)
=> n\(_{Fe}\)= 0,4(mol)
Ta lại có: m\(_{H_2SO_4}\)= 24,5(g)
=> n\(_{H_2SO_4}\)=0,25(mol)
Ta có tỉ lệ:
n\(_{Fe}\)=0,4 > n\(_{H_2SO_4}\)=0,25
=> Fe phản ứng dư, H\(_2\)SO\(_4\) phản ứng hết
a) m\(_{Fepứ}\)= 0,25.56= 14(g)
m\(_{Fedư}\)= 22,4- 14= 8,4(g)
b) V\(_{H_2}\)= 0,25.22,4= 5,6(g)
c) m\(_{FeSO_4}\)= 0,25.152= 38(g)
a, mH=0,7g
mS=11,2g
mO=22,4g
b, mCa=5g
mC=1,5g
mƠ=6g
c, mBa=6,85g
mO=1,6g
mH=0,1g
d, mH=1g
mCl=35,5g
a) \(n_{H_2SO_4}=\dfrac{34,3}{98}=0,35\left(mol\right)\)
Ta có: \(n_H=2n_{H_2SO_4}=2\times0,35=0,7\left(mol\right)\)
\(\Rightarrow m_H=0,7\times1=0,7\left(g\right)\)
Ta có: \(n_S=n_{H_2SO_4}=0,35\left(mol\right)\)
\(\Rightarrow m_S=0,35\times32=11,2\left(g\right)\)
Ta có: \(n_O=4n_{H_2SO_4}=4\times0,35=1,4\left(mol\right)\)
\(\Rightarrow m_O=1,4\times16=22,4\left(g\right)\)
b)\(n_{CaCO_3}=\dfrac{12,5}{100}=0,125\left(mol\right)\)
Ta có: \(n_{Ca}=n_C=n_{CaCO_3}=0,125\left(mol\right)\)
\(\Rightarrow m_{Ca}=0,125\times40=5\left(g\right)\)
\(m_C=0,125\times12=1,5\left(g\right)\)
Ta có: \(n_O=3n_{CaCO_3}=3\times0,125=0,375\left(mol\right)\)
\(\Rightarrow m_O=0,375\times16=6\left(g\right)\)
c) \(n_{Ba\left(OH\right)_2}=\dfrac{8,55}{171}=0,05\left(mol\right)\)
Ta có: \(n_{Ba}=n_{Ba\left(OH\right)_2}=0,05\left(mol\right)\)
\(\Rightarrow m_{Ba}=0,05\times137=6,85\left(g\right)\)
Ta có: \(n_O=n_H=2n_{Ba\left(OH\right)_2}=2\times0,05=0,1\left(mol\right)\)
\(\Rightarrow m_O=0,1\times16=1,6\left(g\right)\)
\(m_H=0,1\times1=0,1\left(g\right)\)
d) \(n_{HCl}=\dfrac{36,5}{36,5}=1\left(mol\right)\)
Ta có: \(n_H=n_{Cl}=n_{HCl}=1\left(mol\right)\)
\(\Rightarrow m_H=1\times1=1\left(g\right)\)
\(m_{Cl}=1\times35,5=35,5\left(g\right)\)