\(3,\\ a,CTTQ:Al_x^{III}Cl_y^I\Rightarrow x\cdot III=y\cdot I\Rightarrow\dfrac{x}{y}=\dfrac{1}{3}\Rightarrow x=1;y=3\\ \Rightarrow AlCl_3\\ b,CTTQ:Ca_x^{II}\left(CO_3\right)_y^{II}\Rightarrow x\cdot II=y\cdot II\Rightarrow\dfrac{x}{y}=1\Rightarrow x=1;y=1\\ \Rightarrow CaCO_3\)
\(4,\\ a,Zn+2HCl\rightarrow ZnCl_2+H_2\\ b,2HCl+MgO\rightarrow MgCl_2+H_2O\\ c,2KClO_3\rightarrow^{t^o}2KCl+3O_2\\ d,2HgO\rightarrow^{t^o}2Hg+O_2\)
\(1,\)
Gọi hóa trị Cu là x
\(\Rightarrow Cu_2^xO_1^{II}\Rightarrow x\cdot2=II\cdot1\Rightarrow x=1\\ \Rightarrow Cu\left(I\right)\)
\(2,\\ a,D_{N_2/kk}=\dfrac{M_{N_2}}{29}=\dfrac{28}{29}\approx0,9655\\ b,n_{NaOH}=0,5\cdot40=20\left(g\right)\\ c,\%N=\dfrac{14}{39+14+16\cdot3}\cdot100\%\approx13,86\%\\ c,n_{CaCO_3}=\dfrac{10}{40+12+16\cdot3}=0,1\left(mol\right)\)
