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Chemistry (Enthalpy) Problem
#5
Okay I looked up some constants. I hope they're right.

Q = mst

T is the change in temperature. 113 - 30 = 83 Celsius.

Specific heat of water is 4.186.

Mass is 377 grams.

Q = (83) (377) (4.186)
Q = 130984 Joules = 130.98 kilo Joules

Now we need to find a constant that methane burns at. I'm not too sure about this one. I looked at the back of my book and got the heat of FORMATION to be -74.8. But I also googled it and got that it could be 55. Both in kilojoules.

So we do 130.98/74.8 (or 130.98/55) to get the number of moles of methane needed.

I get 1.75 moles (or 2.38 moles).

Then to get grams. Carbon weighs 12 grams, 4 x Hydrogen weighs 1 gram. 16 grams total.

16 Molecular mass x 1.75 moles = 28 grams. (Or 2.38 x 16 = 38.08 grams)

So 28 or 38. Maybe. I'm not sure, this question gives little information.
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Messages In This Thread
Chemistry (Enthalpy) Problem - by Panacea - 2011-04-02, 11:32 PM
Chemistry (Enthalpy) Problem - by Shidoshi - 2011-04-03, 03:30 AM
Chemistry (Enthalpy) Problem - by Panacea - 2011-04-03, 03:43 AM
Chemistry (Enthalpy) Problem - by Panacea - 2011-04-11, 08:09 AM
Chemistry (Enthalpy) Problem - by OB3LISK - 2011-04-12, 09:21 PM
Chemistry (Enthalpy) Problem - by Panacea - 2011-04-12, 11:40 PM
Chemistry (Enthalpy) Problem - by OB3LISK - 2011-04-13, 08:06 AM

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