48)
Phản ứng xảy ra:
\(Zn + 2HCl\xrightarrow{{}}ZnC{l_2} + {H_2}\)
\(Fe + 2HCl\xrightarrow{{}}FeC{l_2} + {H_2}\)
Ta có:
\({n_{{H_2}}} = \frac{{0,448}}{{22,4}} = 0,02{\text{ mol}} \to {{\text{n}}_{HCl}} = 2{n_{{H_2}}} = 0,04{\text{ mol}}\)
BTKL:
\(m + {m_{HCl}} = {m_{muối}} + {m_{{H_2}}}\)
\( \to m + 0,04.36,5 = 3 + 0,02.2\)
\( \to m = 1,58{\text{ gam}}\)
49)
Phản ứng xảy ra:
\(Mg + 2HCl\xrightarrow{{}}MgC{l_2} + {H_2}\)
Ta có:
\({n_{{H_2}}} = \frac{{0,448}}{{22,4}} = 0,02{\text{ mol = }}{{\text{n}}_{Mg}}\)
\( \to {m_{Mg}} = 0,02.24 = 0,48{\text{ gam}} \to {{\text{m}}_{Cu}} = 2,4 - 0,48 = 1,92{\text{ gam}}\)