$#Dino$
PTHH: `2Mg + O_{2}` $\overset{t^o}\to$ `2MgO`
`a) n_{Mg}=3,6:24=0,15(mol)`
`→n_{O2}=(0,15.1)/2=0,075(mol)`
`→V_{O2}=22,4.0,075=1,68(l)`
`b) PTHH:` `2KClO_{3}` $\overset{t^o}\to$ `2KCl + 3O_{2}`
`→n_{KClO3}=(0.075.2)/3=0,05(mol)`
`→m_{KClO3}=0,05.122,5=6,125(g)`