N₂ - 0CO₂ - +4NaCl - +1 for Na; -1 for ClH₂S - -2 for H; +2 for SK₂S - +1 for K; -2 for SCaCO₃ - +2 for Ca; +4 for C; -2 for each O
N₂ - 0
CO₂ - +4
NaCl - +1 for Na; -1 for Cl
H₂S - -2 for H; +2 for S
K₂S - +1 for K; -2 for S
CaCO₃ - +2 for Ca; +4 for C; -2 for each O