Đáp án:
\({{\text{V}}_{{H_2}}} = 5,04{\text{ lít}}\)
\({{\text{m}}_{Fe}} = 8,4{\text{ gam}}\)
Giải thích các bước giải:
Phản ứng xảy ra:
\(F{e_2}{O_3} + 3{H_2}\xrightarrow{{{t^o}}}2Fe + 3{H_2}O\)
Ta có:
\({n_{F{e_2}{O_3}}} = \frac{{12}}{{56.2 + 16.3}} = \frac{{12}}{{56.2 + 16.3}} = 0,075{\text{ mol}}\)
Ta có:
\({n_{{H_2}}} = 3{n_{F{e_2}{O_3}}} = 0,075.3 = 0,225{\text{ mol}} \to {{\text{V}}_{{H_2}}} = 0,225.22,4 = 5,04{\text{ lít}}\)
Ta có:
\({n_{Fe}} = 2{n_{F{e_2}{O_3}}} = 0,15{\text{ mol}} \to {{\text{m}}_{Fe}} = 0,15.56 = 8,4{\text{ gam}}\)
\(Zn + 2HCl\xrightarrow{{}}ZnC{l_2} + {H_2}\)
Ta có:
\({n_{Zn}} = \frac{{22,57}}{{65}} = 0,347{\text{ mol;}}{{\text{n}}_{HCl}} = \frac{{29,2}}{{36,5}} = 0,8{\text{ mol > 2}}{{\text{n}}_{Zn}}\)
Vậy HCl dư
\( \to {n_{HCl{\text{ dư}}}} = 0,8 - 0,347.2 = 0,106{\text{ mol}} \to {{\text{m}}_{HCl{\text{ dư}}}} = 0,106.36,5 = 3,869{\text{ gam}}\)