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Q: Chemistry - Heat Energy Liberated ( No Answer,   2 Comments )
Subject: Chemistry - Heat Energy Liberated
Category: Science > Chemistry
Asked by: medicine_man-ga
List Price: $4.50
Posted: 10 Oct 2006 16:21 PDT
Expires: 10 Oct 2006 23:30 PDT
Question ID: 772465
Need pointed in the right direction for the following type of equations please.


Given the following equation for the burning of propane gas:

C3H8(g) + 5O2(g)--> 3CO2(g) + 4H2O(l) (changes in Enthalpy) = -2220kJ mol-1

Calculate the energy in kJ liberated when 78.6g of propane is
combusted in the presense of excess O2.

Please show me workings for how you get to your answer. So I can get
on top of this one. Cheers.
There is no answer at this time.

Subject: Re: Chemistry - Heat Energy Liberated
From: dr_morph-ga on 10 Oct 2006 20:01 PDT
mol C3H8 = 78.6/molar mass = 78.6/44 = 1.786 mol
energy released, i.e. change in Enthalpy = -2220kJ/mol
Therefore: -2220kJ/mol X 1.786 mol = -3964.92 kJ
Subject: Re: Chemistry - Heat Energy Liberated
From: medicine_man-ga on 10 Oct 2006 23:29 PDT

Thanks alot.

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