transfer heat from a cold object to a hot object- violates 2nd thermo law why?

[cherik]

Why does transfering heat from a cold object to a hot object violate the 2nd law of thermodynamics?

[swansont]

Because to do so spontaneously would reduce the entropy of a system. You can do it — we have refrigerators and air conditioners — but you have to do work and reject heat elsewhere.

[chemhero]

Why does transfering heat from a cold object to a hot object violate the 2nd law of thermodynamics?

 

 

Think about it - heat from a cold object to make a hot object hotter

 

Dosnt seem right does it?

 

Energy dissipates out, this way the overal entropy of the universe is higher and we are closer to the inevitable doom

 

Matt

[Infinitus]

Energy is the key here, Basically which is stronger? the Energy level or the Entropy level. For the example of an ice box the electricity is providing the energy or the enthalpy required to overcome the entropy.

[John Cuthber]

My thermodynamics is a bit rusty but I don't think energy is the key here. If I move a Joule of energy from a cold thing to a hot thing then, overall, the system's energy is the same. On the other hand I have changed the entropy.

[swansont]

It is energy, but it's the Gibbs or Helmholtz free energy, which have a -TS term in them. So they will not tend to be spontaneous if temperature decreases, unless the U or pV term (in the Gibbs free energy) change is larger. As far as I can recall, anyway (my thermo has some ferric oxidation as well)