Chenmitry

[ourphx]

How many CO₂moles are needed to react completely with 7.2 moles of C₆H₁₄?

2 C₆H₁₄(g) + 19 O₂(g) - > 12 CO₂(g) + 14 H₂O(g)

I had 620.43g C₆H₁₄ X 1 mol C₆H₁₄/86.17 g C₆H₁₄ X 12 mole CO₂/2 mol C₆H₁₄ X 44.01g CO₂/ 1mole CO₂

Answer in book is 68 moles? Not my answeer. How am I setting this up wrong??

[engineer7]

Are you sure you are asked about CO₂ moles. not about O₂ moles?

Anyway, given the starting quantity 7.2 moles of C₆H₁₄ is 3.6 times bigger than original 2 moles in the equation, you need 3.6 times of the original number of O₂ moles:
3.6 x 19 moles = 68.4 moles of O₂

Or, if the question "how many moles of CO₂ will be produced from 7.2 moles of C₆H₁₄?", then:

3.6x12 (original number of moles in the equation)=43.2

[ourphx]

You are correct the question asks for O₂.

Thanks for your reply!