a)
Các phản ứng xảy ra:
\(3Fe + 2{O_2}\xrightarrow{{{t^o}}}F{e_3}{O_4}\)
\(4Al + 3{O_2}\xrightarrow{{{t^o}}}2A{l_2}{O_3}\)
\(2Zn + {O_2}\xrightarrow{{{t^o}}}2ZnO\)
\( \to {n_{{O_2}}} = \frac{2}{3}{n_{Fe}} + \frac{3}{2}{n_{Al}} + \frac{1}{2}{n_{Zn}}\)
\( = \frac{2}{3}.0,5 + \frac{3}{2}.1,25 + \frac{1}{2}.1,5 = \frac{{71}}{{24}}\)
\( \to {m_{{O_2}}} = \frac{{71}}{{24}}.32 = 94,67{\text{ gam}}\)
b)
Các phản ứng xảy ra:
\(4P + 5{O_2}\xrightarrow{{{t^o}}}2{P_2}{O_5}\)
\(S + {O_2}\xrightarrow{{{t^o}}}S{O_2}\)
\(C + {O_2}\xrightarrow{{{t^o}}}C{O_2}\)
\({n_P} = \frac{{3,1}}{{31}} = 0,1{\text{ mol;}}{{\text{n}}_S} = \frac{{6,4}}{{32}} = 0,2{\text{ mol}}\)
\({{\text{n}}_C} = \frac{{3,6}}{{12}} = 0,3{\text{ mol}}\)
\( \to {n_{{O_2}}} = \frac{5}{4}{n_P} + {n_S} + {n_C} = 0,625{\text{ mol}}\)
\( \to {m_{{O_2}}} = 0,625.32 = 20{\text{ gam}}\)
c)
Các phản ứng xảy ra:
\(C{H_4} + 2{O_2}\xrightarrow{{{t^o}}}C{O_2} + 2{H_2}O\)
\(2CO + {O_2}\xrightarrow{{{t^o}}}2C{O_2}\)
\(2{C_4}{H_{10}} + 13{O_2}\xrightarrow{{{t^o}}}8C{O_2} + 10{H_2}O\)
\({n_{C{H_4}}} = \frac{{1,6}}{{16}} = 0,1{\text{ mol;}}{{\text{n}}_{CO}} = \frac{{2,8}}{{28}} = 0,1{\text{ mol}}\)
\({{\text{n}}_{{C_4}{H_{10}}}} = \frac{{0,58}}{{58}} = 0,01{\text{ mol}}\)
\( \to {n_{{O_2}}} = 2{n_{C{H_4}}} + \frac{1}{2}{n_{CO}} + \frac{{13}}{2}{n_{{C_4}{H_{10}}}}\)
\( = 0,1.2 + \frac{{0,1}}{2} + 0,01.\frac{{13}}{2} = 0,315{\text{ mol}}\)
\( \to {m_{{O_2}}} = 0,315.32 = 10,08{\text{ gam}}\)
