notam E = elementul,
=> oxidul = EO
ms= 50g c% = 29,2%
c% = mdx100/ms
=> md = msxc%/100
= 50x29,2/100 = 14,6 g HCl
M.HCl = 1+35,5 = 36,5 g/mol
8g 14,6g
EO + 2HCl --> ECl2 + H2O
M 2x36,5
=> M = 8x2x36,5/14,6 = 40 g/mol
=> A(E) + 16 = 40 => A(E) = 24
=> E = Mg
=> oxidul = MgO