Combustion Reaction
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Combustion Reaction
Does anyone have any methods for memorizing and/or understanding the various types of enthalpies?
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- Posts: 101
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Re: Combustion Reaction
Hello,
I don't think we need to memorize any enthalpy values specifically, but this is how I think about some of the different types and how to use them:
- bond enthalpy: always positive because it will represent how much energy it takes to break the bond (if you're breaking the bond, add the bond enthalpy; if you're forming it, subtract the bond enthalpy)
- enthalpy of combustion: refers to the enthalpy of combusting one mole of the hydrocarbon fuel
- enthalpy of formation: how much heat it takes to form that thing (if the species is a product, then add its enthalpy of formation; if it's a reactant, subtract the bond enthalpy because it is being broken down and thus that enthalpy of formation is being released)
- enthalpy of reaction: how much heat it takes for that reaction with those exact molar ratios to occur
- enthalpy of fusion: this isn't a super scientifically accurate metaphor, but I think of ice "fusing together" when it melts into water --> enthalpy of fusion = solid to liquid
- enthalpy of vaporization: vaporization = evaporation = liquid to gas
- enthalpy of sublimation: solid to gas (it's the only one left)
Hope this helps!
I don't think we need to memorize any enthalpy values specifically, but this is how I think about some of the different types and how to use them:
- bond enthalpy: always positive because it will represent how much energy it takes to break the bond (if you're breaking the bond, add the bond enthalpy; if you're forming it, subtract the bond enthalpy)
- enthalpy of combustion: refers to the enthalpy of combusting one mole of the hydrocarbon fuel
- enthalpy of formation: how much heat it takes to form that thing (if the species is a product, then add its enthalpy of formation; if it's a reactant, subtract the bond enthalpy because it is being broken down and thus that enthalpy of formation is being released)
- enthalpy of reaction: how much heat it takes for that reaction with those exact molar ratios to occur
- enthalpy of fusion: this isn't a super scientifically accurate metaphor, but I think of ice "fusing together" when it melts into water --> enthalpy of fusion = solid to liquid
- enthalpy of vaporization: vaporization = evaporation = liquid to gas
- enthalpy of sublimation: solid to gas (it's the only one left)
Hope this helps!
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