C8:
a) 2Mg + O2 --to--> 2MgO
b) Theo ĐLBTKL: \(m_{Mg}+m_{O_2}=m_{MgO}\) (1)
=> \(n_{O_2}=8-4,8=3,2\left(g\right)\)
c9
a) Áp dụng quy tắc hóa trị => CTHH: SO3
b) \(\left\{{}\begin{matrix}\%S=\dfrac{1.32}{80}.100\%=40\text{%}\\\%O=\dfrac{3.16}{80}.100\%=60\%\end{matrix}\right.\)