Heat Required to Heat a Substance

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Rakhi Ratanjee 1D
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Joined: Fri Sep 29, 2017 7:04 am

Heat Required to Heat a Substance

Postby Rakhi Ratanjee 1D » Sun Mar 11, 2018 3:20 pm

One of the practice problems states: "Which requires more heat: 1 mol H2(g) or 1 mol butane (g). How are we supposed to figure out which one requires more heat?

Tiffany 1B
Posts: 32
Joined: Fri Sep 29, 2017 7:05 am

Re: Heat Required to Heat a Substance

Postby Tiffany 1B » Sun Mar 11, 2018 3:29 pm

Hi, One of the easiest ways to determine this is the complexity of the molecule. In this case, butane has much more complexity. Hope that helps

miznaakbar
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Re: Heat Required to Heat a Substance

Postby miznaakbar » Sun Mar 11, 2018 3:31 pm

The question seems to be referring to the specific/molar heat capacity of these two substances, so it is asking which substance requires more heat to raise 1 mol by 1 degree Celsius. You would need to look at a table of values of specific and molar heat capacities to determine whether water or butane requires more heat to raise the temperature.

Annalise Eder 2L
Posts: 49
Joined: Sat Jul 22, 2017 3:01 am

Re: Heat Required to Heat a Substance

Postby Annalise Eder 2L » Sun Mar 11, 2018 4:17 pm

More complex molecules generally have high heat capacities because they have more degrees of freedom and more ways to store energy. Materials with more atoms per unit volume will generally have higher heat capacities.

Annie Lieu-1H
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Re: Heat Required to Heat a Substance

Postby Annie Lieu-1H » Mon Mar 12, 2018 9:51 am

The problem deals with molecular complexity regarding heat capacities. Heat capacities are always higher for more complex molecules because it takes more energy to break more bonds/etc. In this particular problem, we can see butane contains much more molecular complexity than H2, who only has one bond.

So butane requires more heat (higher heat capacity).

Clarissa Molina 1D
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Joined: Fri Sep 29, 2017 7:04 am

Re: Heat Required to Heat a Substance

Postby Clarissa Molina 1D » Mon Mar 12, 2018 3:14 pm

For test 1 question 3, it states "when a balloon filled with gas is expanded to a larger volume and lower pressure while maintaining the same temperature," how is heat being transferred in this process?


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