Inorganic Chemistry> How could sign convections of work done ...

How could sign convections of work done by the system and work done on the system be different in physics and chemistry

keero , 9 Years ago

Grade 12

2 Answers

grenade

Last Activity: 9 Years ago

it's just a convention in physics we are more interested in getting some work output say a mechanical device , engine etc while in chemistry we are more concerned with the internal energy things so we do so in both the cases the result is same physics case : du = dq - dw , doing work on system increases ineternal energy as dw = negative for work donw on system and vice versa chem case : du = dq + dw ; doing work on system will increase the internal energy of the system as dw = positive which is obvious and vice versa we can take any sign convention in a given problem but we should be consistent with that throughout the problem to avoid confusion and mistake

Gman Namg

Last Activity: 9 Years ago

Alright, in chemistry, we are concerned about the stability of the products. Thus, when work is done by reactants, if it's negative, meaning energy is lost and the products are more stable than the reactants. In physics, we are more concerned about the energy we can harness from a process. So, when work is done by a system, say a Carnot engine, it is taken to be positive and we can use this energy to do useful work.