Bài tập 1:
3Fe+2O2\(\overset{t^0}{\rightarrow}\)Fe3O4
\(n_{O_2}=\dfrac{m}{M}=\dfrac{51,2}{32}=1,6mol\)
\(n_{Fe_3O_4}=\dfrac{1}{2}n_{O_2}=\dfrac{1,6}{2}=0,8mol\)
\(m_{Fe_3O_4}=0,8.232=185,6gam\)
\(n_{Fe}=\dfrac{3}{2}n_{Fe_3O_4}=\dfrac{3}{2}.1,6=2,4mol\)
\(m_{Fe}=2,4.56=134,4gam\)
C+O2\(\overset{t^0}{\rightarrow}\)CO2
\(n_C=\dfrac{m}{M}=\dfrac{2,4}{12}=0,2mol\)
\(n_{CO_2}=n_{O_2}=n_C=0,2mol\)
\(m_{CO_2}=0,2.44=8,8gam\)
\(m_{O_2}=0,2.32=6,4gam\)
Bài tập 3:
8Al+3Fe3O4\(\overset{t^0}{\rightarrow}\)4Al2O3+9Fe
\(n_{Fe}=\dfrac{m}{M}=\dfrac{5,04}{56}=0,09mol\)
\(n_{Al}=\dfrac{8}{9}n_{Fe}=\dfrac{8}{9}.0,09=0,08mol\)
\(m_{Al}=0,08.27=2,16gam\)
\(n_{Fe_3O_4}=\dfrac{3}{9}n_{Fe}=\dfrac{3}{9}.0,09=0,03mol\)
\(m_{Fe_3O_4}=0,03.232=6,96gam\)
Bài tập 4:
Mg+2HCl\(\rightarrow\)MgCl2+H2
-Gọi số mol Mg phản ứng là x mol
Mg+2HCl\(\rightarrow\)MgCl2+H2
x\(\rightarrow\)...2x............x........x
-Ta có: 36,5.2x-2x=14,2\(\rightarrow\)71x=14,2\(\rightarrow\)x=0,2mol
\(m_{Mg}=0,2.24=4,8gam\)
Bài tập 5:
Ag2SO4\(\overset{t^0}{\rightarrow}\)2Ag+SO2+O2
\(n_{Ag}=\dfrac{m}{M}=\dfrac{21,6}{108}=0,2mol\)
\(n_{O_2}=\dfrac{m}{M}=\dfrac{3,2}{32}=0,1mol\)
\(n_{SO_2}=\dfrac{1}{2}n_{Ag}=n_{O_2}=0,1mol\)
m\(m_{SO_2}=0,1.64=6,4gam\)