Question

HELP HAVE NO CLUE WHAT TO DO !!!! ()_()

Answer 1

This is a bit long to do all of them, so I will give an example for one of the more complicated ones...
#9: \(2\text{C}_7\text{H}_6\text{O}_2+15\text{O}_2\rightarrow 15\text{CO}_2+6\text{H}_2\text{O}\)
What you have to do is make sure that the same number of toms of each type is the same on both sides of the arrow.

For example, in \(2\text{C}_7\text{H}_6\text{O}_2\), the 7 tells you that you have 7 atoms of carbon. The 2 infront of the molecule tells you that you have 2 times the number of this molecule. So, in total, there are 2*7 = 14 carbon (C) atoms.

So:
Left side:
C: 2*7 = 14
H: 2*6 = 12
O: 2*2 + 15*2 = 34

Right Side:
C: 14*1 = 14
H: 6*2 = 12
O: 14*2 + 6*1 = 34

Thus, the number of atoms on both sides of the arrow is the same for ALL the atoms involved, so the equation is balanced.

Answer 2

An example of an unbalnced equation:
#3:

Left side:
Hg: 1
O: 1

Right side:
Hg: 1
O: 2

The number of atoms don't agree for the Oxygen atom, so it is not balanced.

Answer 3

Oh I made a typo writing #9's equation... the right side should say 14 CO2 (but the answer I gave is correct and is using the correct numbers).