perhatikan persamaan reaksi ( belum setara) berikut. M2O3 + CO → MO + CO2 jika 2,8 grm CO bereaksi sempurna menghasilkan 14,4 grm MO (Ar O = 16, C= 12) Ar M ada

Reaksi sudah setara :
M2O3 + CO ==> 2 MO + CO2

m CO = 2,8 gram
m MO = 14,4 gram

Mr CO = Ar C + Ar O
= 12 + 16
= 28

n CO = m / Mr
= 2,8 gram / 28
= 0,1 mol

n MO = n MO
( m MO / Mr MO ) = ( koef. MO / koef. CO ) × n CO
( 14,4 gram / Mr ) = 2/1 × 0,1 mol
14,4 gram / Mr = 0,2 mol
Mr = 72

Mr MO = Ar M + Ar O
Ar M = Mr MO - Ar O
Ar M = 72 - 16
Ar M = 56