# How do I balance C3H5N3O9 --> CO2 + N2 + H2O + O2 I know the answer is: 4C3H5N3O9 --> 12CO2 + 6N2 + 10H2O + 13O2?

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• 1 year ago

If you want to see a slightly different approach, please go here:

https://www.chemteam.info/Equations/Balance-Equati...

and look at problem #40.

The difference is that I started with hydrogen wile the other two (ignore Old Science Guy) start with carbon. It's not a critical difference, just a stylistic decision as to where to start.

• Huh
Lv 6
1 year agoReport

In my matrix approach I started with everything.

• 1 year ago

...

try this handy trick

balance with fractions as needed

then multiply by the LCD to get rid of fractions

C3H5N3O9 --> 3CO2 + 3/2 N2 + 5/2 H2O + 1/4 O2

(found O2 by 9 - 6 - 5/2 = 1/2 then 1/2 / 2 = 1/4)

LCD is 4

so

4 C3H5N3O9 --> 12 CO2 + 6 N2 + 10 H2O + O2

When you get a good response,

This is the only reward we get.

• 1 year ago

C₃H₅N₃O₉ → CO₂ + N₂ + H₂O + O₂

Start with the least common elements. Notice that O shows up in 4 compounds, but C, H, and N only show up in 2 compounds each.

Starting with C:

C₃H₅N₃O₉ → 3 CO₂ + N₂ + H₂O + O₂

Now H:

C₃H₅N₃O₉ → 3 CO₂ + N₂ + 5/2 H₂O + O₂

Now we balance N:

C₃H₅N₃O₉ → 3 CO₂ + 3/2 N₂ + 5/2 H₂O + O₂

Finally, balance O:

C₃H₅N₃O₉ → 3 CO₂ + 3/2 N₂ + 5/2 H₂O + 1/4 O₂

Quadruple to get rid of the fractions:

4 C₃H₅N₃O₉ → 12 CO₂ + 6 N₂ + 10 H₂O + O₂

• 1 year ago

The "answer" you know is wrong. The oxygen atoms aren't even close to balanced.

Starting from the beginning:

C3H5N3O9 → CO2 + N2 + H2O + O2

Balance the carbon:

C3H5N3O9 → 3 CO2 + N2 + H2O + O2

Balance the nitrogen:

C3H5N3O9 → 3 CO2 + 1.5 N2 + H2O + O2

Balance the hydrogen:

C3H5N3O9 → 3 CO2 + 1.5 N2 + 2.5 H2O + O2

Multiply everything by 2 to get rid of the fractions:

2 C3H5N3O9 → 6 CO2 + 3 N2 + 5 H2O + 2 O2

Now you've got 2 x 9 = 18 oxygens on the left, and 6 x 2 + 5 + 2 x 2 = 21 oxygens on the right.

You can't change the left side or CO2 or H2O without messing up the balances for C or H, so you must adjust the O2 on the right, which has 21 - 18 = 3 too many oxygen atoms, so subtract 3 atoms of O on the right:

2 C3H5N3O9 → 6 CO2 + 3 N2 + 5 H2O + 0.5 O2

Now the equation is completely balanced, but you still have a forbidden fraction, so multiply everything by 2 again:

4 C3H5N3O9 → 12 CO2 + 6 N2 + 10 H2O + O2