\(a,PTHH:2Mg+O_2\underrightarrow{t^o}2MgO\\ b,n_{MgO}=\dfrac{m}{M}=\dfrac{8}{40}=0,2\left(mol\right)\\ Theo.PTHH:n_{Mg}=n_{MgO}=0,2\left(mol\right)\\ m_{Mg}=n.M=0,2.24=4,8\left(g\right)\)
\(n_{MgO}=\dfrac{8}{40}=0,2\left(mol\right)\)
a) PTHH : 2Mg + O2 -> 2MgO
\(m_{O_2}=0,2.32=6,4\left(g\right)\)
b) Theo ĐLBTKL
\(m_{Mg}+m_{O_2}=m_{MgO}\)
\(=>m_{Mg}=8-6,4=1,6\left(g\right)\)
2Mg+O2-to>2MgO
0,2-----------------0,2 mol
=>n MgO=\(\dfrac{8}{40}\)=0,2 mol
=>m Mg=0,2.24=4,8g