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Topic: Finding grams when given grams  (Read 4679 times)

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rainrider

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Finding grams when given grams
« on: March 29, 2006, 08:17:31 PM »
Ok, I know I'm missing something, but I can't figure out what...

I'm given the following:

How many grams of CO2 is released when 1kg of C8H18 combusts.

I set up and balance the formula:

2C8H18 + O2 --> 16CO2 + 18H2O

Now, as I understand it (which is apparently wrong), you use the ratio of moles of octane (C8H18) to carbon dioxide to calculate the actual number of grams you would get out, as such:

1000g octane x (1 mol octane)/(384.08g) x (8 mol CO2/1 mol octane) x (44.01g CO2/1 mol CO2) = 916.7g of CO2.

The answer the book gives is 3.1kg of CO2.

I'm not sure where I'm going wrong...does someone else know?

Thanks!

Offline AWK

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Re:Finding grams when given grams
« Reply #1 on: March 30, 2006, 03:04:54 AM »
C8H18 + 12.5O2 --> 8CO2 + 9H2O
Calculate correctly mole of octane!
AWK

Offline tennis freak

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Re: Finding grams when given grams
« Reply #2 on: May 19, 2006, 09:37:53 PM »
C8H18 + 12.5O2 --> 8CO2 + 9H2O
Calculate correctly mole of octane!

once you get the correct balanced formula you use the same exact equation you did like this

1000 g C8H18 * (1mole/114g) * (8 mole CO2/1mole C8H18) * (44gCO2/1moleCO2)= 3087.72 g CO2 which translates to about 3.1 kg CO2 depending on how you rounded
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