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March 28, 2024, 10:37:50 pm

Author Topic: why does methane have a higher heat of combustion than methanol?  (Read 1000 times)  Share 

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thatdumbstudent

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why does methane have a higher heat of combustion than methanol?
« on: February 23, 2020, 03:05:38 pm »
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I thought methanol would be higher since it has the oxygen?

thatdumbstudent

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Re: why does methane have a higher heat of combustion than methanol?
« Reply #1 on: February 23, 2020, 03:19:02 pm »
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I thought methanol would be higher since it has the oxygen?
i think I might get it now... so the heat of combustion of methanol is actually higher since it is a negative value...?

thatdumbstudent

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Re: why does methane have a higher heat of combustion than methanol?
« Reply #2 on: February 23, 2020, 03:23:05 pm »
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i think I might get it now... so the heat of combustion of methanol is actually higher since it is a negative value...?

wait omg I think I just cracked it I forgot heat of combustion and enthalpy of combustion are two different things AHHH idk if I should feel smart or dumb and I'm just talking to myself

Erutepa

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Re: why does methane have a higher heat of combustion than methanol?
« Reply #3 on: February 23, 2020, 03:27:04 pm »
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i think I might get it now... so the heat of combustion of methanol is actually higher since it is a negative value...?
Hi!
The negative values you're referring to is actually the change in enthalpy (delta H). When it is written as negative it means the products have less energy than the reactants, thus energy is released in other forms (I.e heat). The more negative delta H is the more energy released. This is related to but not the Same as the heat of combustion (which is a positive value).
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thatdumbstudent

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Re: why does methane have a higher heat of combustion than methanol?
« Reply #4 on: February 23, 2020, 03:34:23 pm »
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Hi!
The negative values you're referring to is actually the change in enthalpy (delta H). When it is written as negative it means the products have less energy than the reactants, thus energy is released in other forms (I.e heat). The more negative delta H is the more energy released. This is related to but not the Same as the heat of combustion (which is a positive value).

Thanks! I get it now :) I actually will have a sac on it tomorrow and it stressed me out loads but I also wasn’t reading stuff properly whoops