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Is heat extensive or intensive property?

I surfed the Internet for the same and found quite different answers. Like, heat is not a property, so it is neither. One said that since heat depends on the amount of substance, it is extensive. I thought about the latter one as well.

So, my question could be primarily divided into:

1. Is heat a property of matter?

2.1. If yes, is it extensive or intensive? Why?

2.2. If no, why?

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    $\begingroup$ Note that the word "heat" might mean "the transfer of thermal energy" (this is the more technical meaning) but it is also sometimes used as an informal shorthand for "thermal energy". The former isn't a property, the latter is an extensive property. This may help explain why you are getting contradictory answers. $\endgroup$
    – Harry Johnston
    Apr 8, 2018 at 3:30
  • $\begingroup$ Can you provide links or references to the two claims (one for "heat is not a property" and "heat depends on amount of substance")? $\endgroup$
    – Kyle Kanos
    Apr 9, 2018 at 10:07

3 Answers 3

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Heat quantifies a type of energy flow, so as energy it is extensive, but it is not a property of matter, in the sense that it is not a state function, but a function of transitions among states.

So:

1. No, is not

2.1 In some sense is extensive, because if I consider two couples of identical systems that exchange energies the exchanged amount is double of only one couple case

2.2 Because is a property of evolution (transitions) not of the states of the matter

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Heat is defined as the transfer of thermal energy! And the thermal energy of a substance can be divided into 2 things: the temperature (average kinetic energy of the particles) and the potential energy (this is energy going towards breaking the bonds in a substance to change its state.)

So, while heat isn’t a property of matter but rather a phenomenon, thermal energy (temperature and state) are!

Temperature would be an intensive property because it doesn’t depend on the amount of substance (a 100 degrees cup of coffee has same temp as a 100 degree drop of coffee), but thermal energy is an extensive property because it does depend on the amount of substance. (A huge cup of hot coffee has more thermal energy than a drop of hot coffee).

Hope that helps!

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Yes, Heat is a property of matter.

Extensive properties (like mass) are dependent upon the amount of a substance, while intensive properties (like density) are independent of quantity. Heat shall not be confused with temperature. Heat is an extensive property, and is proportional to the total energy of all atoms in an object. Temperature, on the other hand, is an intensive property, as it is proportional to the average energy per atom.

For instance, 2 tubs of water of different volumes can be at $80^oC$, but the one with a larger volume possesses more heat energy.

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  • $\begingroup$ I would like to know why my answer is downvoted for no apparent reason. $\endgroup$
    – QuIcKmAtHs
    Apr 8, 2018 at 3:54
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    $\begingroup$ Heat is the transfer of thermal energy, you're the mixing two up. $\endgroup$
    – glaba
    Apr 8, 2018 at 4:25

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