Why is the sign convention of heat and work done i

Question

Why is the sign convention of heat and work done in chemistry opposite of that in physics in the chapter thermodynamics? Please explain in detail it`s very confusing 😓😕😟

Arun · Accepted Answer

Dear Piyush

In thermodynamics we have two things :- System and Surrounding

Work(System) + Work(surrounding) = Zero

so, Work(System) = - Work(Surrounding)

Similarly, Heat evolved/absorbed(System) = - Heat evolved/absorbed(Surrounding)

So if you consider one thing (say System) to be of positive sign convention then other thing (Surrounding) becomes negative in sign convention

In physics we give more importance to System. For example we calculate forces, acceleration, velocity etc of a body which constitutes System. Hence System becomes reference in physics. So we give positive sign convention for System.

In Chemistry we give more importance to Surroundings. For example we calculate temperature, pressure etc. of the gases which constitutes Surroundings. Hence Surroundings becomes reference in Chemistry. So we give positive sign convention for Surroundings.

Regards

Arun (askIITians forum expert)

Physical Chemistry> Why is the sign convention of heat and wo...

Why is the sign convention of heat and work done in chemistry opposite of that in physics in the chapter thermodynamics? Please explain in detail it`s very confusing 😓😕😟

Piyush Upadhyay , 7 Years ago

Arun

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Physical Chemistry> Why is the sign convention of heat and wo...

Why is the sign convention of heat and work done in chemistry opposite of that in physics in the chapter thermodynamics? Please explain in detail it`s very confusing 😓😕😟

Piyush Upadhyay , 7 Years ago

Arun

LIVE ONLINE CLASSES

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