Chemistry Help Needed?

Question

Complete and balance the equation for the complete combustion of each of the following.

a. C3H8

b. C5H12

c. CH3OH

d.C12H22O11

Answer 1

I'll do the hardest one and let you do the rest.

Ok so combustion always involves O2 so you need to add +O2 to all of those. The products will all be CO2 and H2O

C12H22O11 + O2=====>CO2 + H2O

Now you just need to get the same amount of each element on each side.

Lets just record how many of each element we have on each side.

Reactant side: 12 C, 22 H and 11 O

Product side: 1 C, 3 O and 2 H

Ok so since we have 12 C on the left side and only 1 on the right side lets add 12 to the right side so that we also have 12 C on the right.

C12H22O11 + O2=====>12CO2 + H2O

Now since there's 22 H on the left side and only 2 on the right side lets add 11 to the right side to make it 22 H on the right side as well.

C12H22O11 + O2=====>12CO2 + 11H2O

Now there's only 2 O on the left side and 35 on the right side. Add 35 in front of the O2 on the left side and multiply everything else by 2.

2C12H22O11 + 35O2=====>24CO2 + 22H2O

There you go. It's balanced. Now you can do the rest.

Answer 2

C3H8 +5O2--->3CO2 +4H2O

Next is done the same.  Balance the C's and then the H's and finally the O's