Make ammonia : 4,2
Separate water : 2,3
Combust methane : 3,3
Further explanation
Maybe the full questions can be seen in the attached picture
Reaction 1 : Make Ammonia
N₂+3H₂⇒2NH₃
molecules left : 1+3=4
molecules right :2
Reaction 2 : Separate Water
2H₂O⇒2H₂+O₂
molecules left : 2
molecules right :2+1=3
Reaction 3 : Combust Methane
CH₄+2O₂⇒CO₂+2H₂O
molecules left : 1+2=3
molecules right :1+2=3
