heat given off by rxn = - heat absorbed by solution

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Michael Du 1E
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Joined: Sun Sep 22, 2019 12:16 am

heat given off by rxn = - heat absorbed by solution

Postby Michael Du 1E » Tue Feb 04, 2020 3:46 pm

For the equation (heat given off by rxn = -heat absorbed by solution), why would the heat that is absorbed by the solution be a negative number? Wouldn't the solution be a positive q if it absorbed the heat? thank you

Vicki Liu 2L
Posts: 101
Joined: Sat Aug 24, 2019 12:15 am

Re: heat given off by rxn = - heat absorbed by solution

Postby Vicki Liu 2L » Tue Feb 04, 2020 3:51 pm

I believe it is not important which side the negative sign is on, as long as you know the heat given off and absorbed are equal in magnitude but opposite signs.

Kayli Choy 2F
Posts: 100
Joined: Sat Aug 24, 2019 12:17 am

Re: heat given off by rxn = - heat absorbed by solution

Postby Kayli Choy 2F » Wed Feb 05, 2020 1:23 pm

I think the correct way to think about it is
-(heat given off by the system reaction) = (heat absorbed by the surroundings)
Because the system is losing heat, there is a negative in front of it, and because the surroundings are gaining heat, that value is positive.

Nick Fiorentino 1E
Posts: 102
Joined: Wed Sep 18, 2019 12:16 am

Re: heat given off by rxn = - heat absorbed by solution

Postby Nick Fiorentino 1E » Wed Feb 05, 2020 2:55 pm

Yeah, whenever a system loses energy in whatever form, that value will be negative. But, that energy must go somewhere else so the energy will be absorbed by another system, so it will be positive for that system

Sally Qiu 2E
Posts: 105
Joined: Fri Aug 30, 2019 12:18 am

Re: heat given off by rxn = - heat absorbed by solution

Postby Sally Qiu 2E » Wed Feb 05, 2020 3:00 pm

the heat given off by the rxn would be absorbed by the surroundings. i'm not sure if you need to know specifically which side the negative is on, as long as one is negative?

605395381
Posts: 50
Joined: Mon Jun 17, 2019 7:24 am

Re: heat given off by rxn = - heat absorbed by solution

Postby 605395381 » Wed Feb 05, 2020 5:31 pm

I don't think it is important to memorize that equation. As long as you understand that losing heat is neg and absorbing is pos. and the amount of energy lost/gain by the system is equal to the amount gain/lost by the surrounding.

WYacob_2C
Posts: 102
Joined: Sat Jul 20, 2019 12:16 am

Re: heat given off by rxn = - heat absorbed by solution

Postby WYacob_2C » Fri Feb 07, 2020 10:53 pm

I believe the correct statement is: -(heat given off by system)=(heat gained by surroundings). This statement is true if the system is isolated because the heat given off my a system must be transferred to the surroundings.


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