need chemistry help

Question

if 2.08 moles of propane (C3Hg) react with excess oxygen in a complete combustion reaction, how many moles of water are produced?

Answer 1

Hello, Molly,

I thought I had answered this, but I don't see it posted. I'll try again.

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We need a balanced equation to start. As Stanton D. points out, I'll assume you didn't intend the propane formula to contain mercury, Hg. I'll assume propane, C₃H₈.

I come up the this balanced equation:

1C₃H₈ + 5O₂ = 3CO₂ + 4H₂O

This tells us that 4 moles of water are produced for every 1 mole of propane. This is a conversion factor for this reaction: (4 moles H₂O/1 mole C₃H₆).

Since we consume all 2.08 moles of propane, we'll produce:

(2.08 moles C₃H₈)*(4 moles H₂O/1 mole C₃H₆) = 8.32 moles H₂O.

Bob