How do we represent the combustion of hexanes? And how do we represent the formation of silver chloride from sodium chloride, and silver nitrate?
Please give your science teacher a break. She might be my colleague!
So, you have to balance 2 unspecified equations. I'll give you 2, which might or not be suitable. Firstly, combustion of hexane (the which drives your motor!):
Is this balanced? And remember that I might be trying to bust your balls because you offered disrespect to your science teacher.
Secondly, precipitation of an insoluble precipitate, say silver chloride:
Both reaction demonstrate stoichiometry; that is for every reactant particle there must be a corresponding product particle. You also practise stoichiometry whenever you make a purchase with cash or make an electronic transaction: for every credit there must be a corresponding debit.