# Heat of combustion for octane

**URL:** <https://boards.straightdope.com/t/heat-of-combustion-for-octane/329808>\
**Category:** Factual Questions\
**Created:** [November 6, 2005, 6:51pm UTC](https://boards.straightdope.com/t/heat-of-combustion-for-octane/329808 "2005-11-06T18:51:54Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![quelquechose](https://avatars.discourse-cdn.com/v4/letter/q/6f9a4e/32.png) [@quelquechose](https://boards.straightdope.com/u/quelquechose)\
**Post date:** [November 6, 2005, 6:51pm UTC](https://boards.straightdope.com/t/heat-of-combustion-for-octane/329808/1 "2005-11-06T18:51:54Z")

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What is the heat of combustion for octane? I can’t find it on google for some reason, and none of my textbooks list heats of combustion for alkanes above pentane. I need a citeable source, but I can’t find anything.

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [November 6, 2005, 7:00pm UTC](https://boards.straightdope.com/t/heat-of-combustion-for-octane/329808/2 "2005-11-06T19:00:35Z")

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n-Octane: 1302.7 kg calories  
CRC Handbook of Chemistry and Physics

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**Author:** ![quelquechose](https://avatars.discourse-cdn.com/v4/letter/q/6f9a4e/32.png) [@quelquechose](https://boards.straightdope.com/u/quelquechose)\
**Post date:** [November 6, 2005, 7:11pm UTC](https://boards.straightdope.com/t/heat-of-combustion-for-octane/329808/3 "2005-11-06T19:11:57Z")

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Excellent. Thanks.

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**Author:** ![quelquechose](https://avatars.discourse-cdn.com/v4/letter/q/6f9a4e/32.png) [@quelquechose](https://boards.straightdope.com/u/quelquechose)\
**Post date:** [November 6, 2005, 7:14pm UTC](https://boards.straightdope.com/t/heat-of-combustion-for-octane/329808/4 "2005-11-06T19:14:37Z")

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Actually, what are the units on that value? Is it at 25 degrees C?

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**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\
**Post date:** [November 6, 2005, 8:04pm UTC](https://boards.straightdope.com/t/heat-of-combustion-for-octane/329808/5 "2005-11-06T20:04:14Z")

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The value is for the liquid, at 20°C and atmospheric pressure.