Goi oxit kim loai la YO
=>Y+16=X
a) Vkk=19,6 lit =>VO2=19,6.20%=3,92 lit
=>nO2=0,175 mol=>mO2=0,175.32=5,6 gam
BT klg=>mM=5,6+10=15,6 gam
b)2X+O2=>2XO va 2Y+O2=>2YO
b=2,5a
nO2=0,5a+0,5b=0,175
=>a=0,1 b=0,25 mol
=>mhh=0,1X+0,25Y=10=>Y=24 va X=40
=>Y la Mg, X la Ca