how can you find the 2nd reactant and the products of a reaction?

Question

here can you help me with these?

1 C12H22O11 + ___________ --> _________ + ____________
2 C7H14 + ____________ --> ____________ + ____________
1 CH4 + 2 __________ --> 1 _____________ + 2 ________
2 C2H6 + _______________ --> __________ + _________

Answer 1

All of these are combustion reactions since (except for first reactant) they are all hydrocarbons.

Combustion reactions always occur in the presence of oxygen gas (O2) and the products are always CO2 and H2O. You should be able to balance these fairly easily.