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/sci/ - Science & Math

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1842998 No.1842998 [Reply] [Original]

hello thar

can anyone tell me how to calculate the enthalpy change of combustion

>> No.1843021

please

>> No.1843039

what conditions do you have - are you given G of product formation? Temp, delta S?

It really depends on what information you're given - else its' like "Help me I have to solve algebra!".

>> No.1843042

>simontamignoreslizvicious.jpg

>> No.1843046

Give me the fucking question, dickhead. I can't read your mind over the internet.

>> No.1843055

enthalpy change must be given in Kjmol-1

(i need the enthalpy change of combustion of ethanol)

i have an energy transfer of 10450 J

and molecular weight of ethanol is 46.0

i dnt know if that helps ive got no idea what to do

>> No.1843098

CH3CH2OH + 3O2 --> 2CO2 + 3H2O

I don't feel like looking up the numbers. But first you'll find the heats of formation for CO2, H2O, and CH3CH2OH (not O2 because it's heat of formation is 0). Multiple each heat of formation by number of moles in the equation (i.e., 2*CO2 heat of formation). Add the results together for the products and for the reactant (not necessary, only one reactant matters).

(Heat of formation of products - Heat of formation for reactants)
should give you the answer.

>> No.1843114

>>1843098
thank u so much