Pentane gas (C5H12) combusts with oxygen gas (O2) to form water (H2O) and carbon dioxide (CO2). Write a balanced chemical equation for this reaction.

The balanced equation for when pentane gas (C5H12) combusts with oxygen gas (O2) to form water (H2O) and carbon dioxide (CO2) is C₅H₁₂ + 8O₂ --> 5CO₂ + 6H₂O.

Expert Answers

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Some of the rules that I usually teach students when manually balancing equations are as follows:

  • If there are carbons, balance them first
  • Balance any monatomic or diatomic molecules last

So, in this case, we do have carbon, so it should be balanced first. We also have oxygen molecules (O₂), so we should balance these last.

Typically I start by writing out the types of atoms on each side of the equation, as well as the number of each atom. I rewrite this after each balancing step.

Reactants: C=5, H=12, O=2

Products: C=1, H=2, O=3

One of the things we can immediately notice is that the product side has an odd number of oxygen molecules, but oxygens are only available to us in evenly numbered amounts (since O₂ is the only source). This means that the products will need...

(The entire section contains 2 answers and 423 words.)

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