persamaan reaksi (belum setara)

M + 2Cl₂ ⇒ MCl₄
n Cl₂ = v (STP) / 22.4 = 56 / 22.4 = 2.5 mol
n M = 1/2 . n Cl₂ = 1.25 mol

1.25 = 35 / Ar
Ar = 28 g/mol