Temperature, Specific Heat, and Kinetic Energy

[FCBarca1990]

---

Members do not see this ad.

Hey guys,

I am a bit confused on the concept of specific heat in relation to temperature and kinetic energy. I was hoping someone could elucidate the topic for me. 🙂

So I understand specific heat in relation to the equation q = mcdT, where a given quantity of heat will cause a change in the temperature of an object.

However, how does this relate to the Zeroth Law of Thermodynamics and kinetic energy of particles? The Zeroth Law more or less states that objects at thermal equilibrium are at the same temperature. At thermal equilibrium, will two objects of the same mass but different specific heat have the same or different temperatures?

Temperature is also proportional to the average kinetic energy of particles in the object. So in the same regard, will two objects of the same mass but different specific heats have the same kinetic energies at a specific temperature or different kinetic energies?

I know that for gases the average kinetic energy is equal to (3/2)RT, but does the same equation apply to solids and liquids? If so, then what is different about two objects of different specific heats but at the same temperature?

 

[SN2ed]

Thread moved. Topics of this nature belong in the Study Q&A forum.

 

[Lokhtar]

I know that for gases the average kinetic energy is equal to (3/2)RT, but does the same equation apply to solids and liquids? If so, then what is different about two objects of different specific heats but at the same temperature?

No. Remember R is the gas constant. Also, molecules within a solid don't really move all that much, so it wouldn't really apply anyway.

At thermal equilibrium, will two objects of the same mass but different specific heat have the same or different temperatures?

Same. Think of it as taking more energy out of one to heat the other by the same amount.

So let's say you have two objects, object A at a temperature of 100 degrees. You have a second object, object B, at zero degrees with a heat capacity of 1. And a third object, Object C, also at zero degrees, with a heat capacity of 5.

So if you put object A and object B next to each other, they'll both reach thermal equilibrium at a higher temperature than object A and C, but in the end, the temperature in both cases will be the same.

For the first case, the temperature of both could be 50, but in the second case, the temperature of both might be 20.