Chem SAT II problem

Test Preparation SAT Subject Test Preparation
1

<p>Hey...this is a word problem that's been giving me a lot of trouble. I think it involves just a bunch of mole-mole conversions but I'm not sure. Anyways, here goes:</p>

<p>A car gets 9.2 kilometers to a liter of gasoline. Assuming that gasoline is 100% octane, C8H18 (which has a specific gravity of 0.69), how many liters of air (21% oxygen by volume at STP) will be required to burn the gasoline for a 1250-km trip? Assume complete combustion.</p>

<p>Thanks in advance for any help, help ASAP is greatly appreciated</p>

2

<p>Write out the balanced equation for the burn.
I would do the working but I'm too lazy.</p>

<p>Find out how many moles of octane is in per litre of "Gasoline"
You'll need around 130 to around 140 litre's of gasoline.</p>

<p>Find out how many moles of oxygen you need.
Then use the 21% ratio and work out how much air you need. Then convert the air from moles into litres.</p>