Câu 1:
Ta có:
\(n_{H2}=0,15\left(mol\right)\)
\(R+HCl\rightarrow RCl+\frac{1}{2}H_2\)
0,3___________________0,15
\(\Rightarrow M_R=\frac{3}{0,3}=10\left(Li,Na\right)\)
Hai kim loại là Liti và Natri
Câu 2:
\(Ba+2H_2O\rightarrow Ba\left(OH\right)_2+H_2\)
a________________________a
\(2Na+2H_2O\rightarrow2NaOH+H_2\)
a_________________________0,5a
\(n_{H2}=0,03\left(mol\right)\Rightarrow a+0,5a=0,03\Rightarrow a=0,02\)
\(\Rightarrow m=m_{Ba}+m_{Na}=137a+23a=3,2\left(g\right)\)
Câu 3:
\(n_{CaO}=0,2\left(mol\right)=n_{Ca\left(OH\right)2}\left(BT:Ca\right)\)
\(n_{CO2}=0,3\left(mol\right)\)
\(Ca\left(OH\right)_2+CO_2\rightarrow CaCO_3+H_2O\)
0,2________0,2_________0,2_________
=> Dư 0,1 mol CO2
\(CO_2+CaCO_3+H_2O\rightarrow Ca\left(HCO_3\right)_2\)
0,1_____0,1_____________
=> Còn lại 0,1 mol CaCO3
\(\Rightarrow m_{\downarrow}=10\left(g\right)\)
