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heat given off by rxn = - heat absorbed by solution

Posted: Tue Feb 04, 2020 3:46 pm
by Michael Du 1E
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

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

Posted: Tue Feb 04, 2020 3:51 pm
by Vicki Liu 2L
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.

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

Posted: Wed Feb 05, 2020 1:23 pm
by Kayli Choy 2F
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.

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

Posted: Wed Feb 05, 2020 2:55 pm
by Nick Fiorentino 1E
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

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

Posted: Wed Feb 05, 2020 3:00 pm
by Sally Qiu 2E
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?

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

Posted: Wed Feb 05, 2020 5:31 pm
by 605395381
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.

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

Posted: Fri Feb 07, 2020 10:53 pm
by WYacob_2C
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.