relationship between q and w

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Amy Zheng 2l
Posts: 57
Joined: Fri Sep 29, 2017 7:04 am

relationship between q and w

Postby Amy Zheng 2l » Fri Jan 19, 2018 5:34 pm

Is there a set rule for the relationship between q and w?

I was thinking that if a reaction is negative q then the system is exothermic so work must be negative since you're loosing energy. If a reaction is positive q then the system is endothermic so work must be positive since you need to input energy. I might be getting this totally wrong but I would like some feedback on this!!

I know question 17 goes directly against this logic. But is it solely because of constant temperature or that each situation is just different?

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

Re: relationship between q and w

Postby Tiffany Dao 1A » Fri Jan 19, 2018 6:50 pm

If q is positive then w is not necessarily positive as well. In 17, heat is absorbed making q positive, but work is being done by the system, which means that w must be negative. q and w are not automatically the same sign.

AlyssaPeckham1A
Posts: 49
Joined: Fri Sep 29, 2017 7:04 am

Re: relationship between q and w

Postby AlyssaPeckham1A » Sat Jan 20, 2018 1:09 pm

The relationship between q and w is also affected by the change in energy of the system which can influence the signs.


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