Two buckets contain water at 30 deegres C one contains 1kg of water and the other contains 2kg of water. State and explain whether the following quantities are the same or different for the water in the two buckets

A. internal energy

B. temperature

C. average energy of a molecule

Answer: Hello!

we have two buckets wit water at 30°C, one of them has 1kg of water, and the other has 2kg of water; we want to see which quantities are the same or different for the water in the two buckets.

A) internal energy: the internal energy is an extensive variable, which means that depends on the amount of mass or particles in the system, then the bucket with 2kg of water has more internal energy than the other bucket, and this has a lot of sense, because you have the double of the mass, which means that in the bucket with 2kg of water you have 1kg of water worth in energy more than the other bucket

b) Temperature; the temperature is an intensive variable, which means that does not depend on the number of particles or mass, then in both buckets, the temperature is the same, 30°C

C) average energy per molecule: This is also an intensive variable that is relational with the temperature and does not depend on the number of molecules that each bucket has, then the molecule in each bucket has the same average energy, but again in one bucket you have the double of molecules than in the other, and each molecule has the same energy, then again you can see that the bucket with more molecules has more internal energy.

The internal energy is different. The number of kg influence the answer. More mass results in more internal energy.

The temperature is the same (given)

The average energy / molecule is the same. The total might be different but the average is going to be the same.