Which q is negative?

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Ishan Saha 1L
Posts: 60
Joined: Fri Sep 29, 2017 7:03 am

Which q is negative?

Postby Ishan Saha 1L » Sun Jan 14, 2018 7:01 pm

Hi! When solving a problem where heat transfers from one object to another, like from copper to water for instance, how do we know which heat is negative and which is positive? I thought that in a situation where heat is being transferred from a piece of copper to the water, the copper would have negative heat since it is releasing heat to its surroundings, but my TA was saying that the heat for water should have the negative sign? Would someone please explain why? Thank you.

Farah Ahmad 2A
Posts: 30
Joined: Thu Jul 27, 2017 3:00 am
Been upvoted: 1 time

Re: Which q is negative?

Postby Farah Ahmad 2A » Sun Jan 14, 2018 7:13 pm

I'm pretty sure if water is absorbing heat its q should be positive. In the textbook it states, "If energy enters a system as heat, the internal energy of the system increases and q is positive; if energy leaves the system as heat, the internal energy of the system decreases and q is negative" (268).

Glendy Gonzalez 1A
Posts: 52
Joined: Fri Sep 29, 2017 7:07 am

Re: Which q is negative?

Postby Glendy Gonzalez 1A » Sun Jan 14, 2018 8:20 pm

-When heat is being transferred into the system, q>0 (q is positive)
-When heat is being transferred out of the system, q<0 (q is negative)


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