a)
\(n_{N_2}=\dfrac{m}{M}=\dfrac{0,28}{28}=0,01\left(mol\right)\)
\(V_{N_2\left(dktc\right)}=n\cdot22,4=0,01\cdot22,4=0,224\left(l\right)\)
b)
\(n_{CuCl_2}=\dfrac{0,3\cdot10^{23}}{6\cdot10^{23}}=0,05\left(mol\right)\\ m_{CuCl_2}=0,05\cdot\left(64+71\right)=6,75\left(g\right)\)
\(m_{ZnCl_2}=n\cdot M=0,2\cdot\left(65+71\right)=27,2\left(g\right)\)