giúp tôi bài 4 5 6 với chiều nay phải học rồi !
cảm ơn nhiều!!!!!!!!!!!!!!!!!
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Bài 1
Coi khối lượng Fe:7 gam
Khối lượng O:3 gam
-> nFe=7:56=0,125 mol
no=3:16=0,1875 mol
Tỉ lệ nFe:no=o,125:0,1875=2:3
->công thức:Fe2O3
b khối lượng mol là:
56* 2+16*3=160
a.
\(\%_{Fe_{\left(Fe_2O_3\right)}}=\dfrac{56.2}{160}.100\%=70\%\)
\(\%_{O_{\left(Fe_2O_3\right)}}=100\%-70\%=30\%\)
b.
\(\%_{C_{\left(C_6H_{12}O_6\right)}}=\dfrac{12.6}{180}.100\%=7\%\)
\(\%_{H_{\left(C_6H_{12}O_6\right)}}=\dfrac{1.12}{180}.100\%=6,7\%\)
\(\%_{O_{\left(C_6H_{12}O_6\right)}}=100\%-7\%-6,7\%=86,3\%\)
c.
\(\%_{C_{\left(\left(C_6H_{10}O_5\right)_n\right)}}=\dfrac{12.6}{162n}.100\%=44,4n\%\)
\(\%_{H_{\left(\left(C_6H_{10}O_5\right)_n\right)}}=\dfrac{1.10}{162n}.100\%=6,2n\%\)
\(\%_{O_{\left(C_6H_{1o}O_5\right)}}=\dfrac{16.5}{162n}.100\%=49,4n\%\)
\(\Rightarrow49,4n\%=100\%-44,4n\%-6,2n\%\)
\(\Leftrightarrow n=1\)
\(\Rightarrow\left\{{}\begin{matrix}\%_C=44,4\%\\\%_H=6,2\%\\\%_O=49,4\%\end{matrix}\right.\)
d.
\(\%_{Na_{\left(NaCl\right)}}=\dfrac{23}{58,5}.100\%=39,3\%\)
\(\%_{Cl_{\left(NaCl\right)}}=100\%-39,3\%=60,7\%\)
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