The Laws of Thermodynamics

Question 1

What is the Zeroth Law of thermodynamics?

Answer 1

If two objects are in thermal equilibrium with a thrid then they are in thermal equilibrium with each other

Question 2

What is the 1st law of thermodynamics?

Answer 2

ΔU = Q + W

The change in internal energy of a system is equal to the heat energy transferred to it plus the work done by the system

[W is negative when work is done on the system and possitive when it is done by the system]

[Q is possitive when heat is gained by the system and negative when heat is lost]

Question 3

What is the 2nd law of thermodynamics?

Answer 3

Heat flows spontaneously from a substance at a higher temperature to a substance at a lower temperature and does not flow spontaneously in the reverse direction

Question 4

What is the 3rd law of thermodynamics?

Answer 4

It is not possible to lower the temperature of any system to absolute zero in a finite number of steps

[the entropy of a perfect crystal at absolute zero is equal to zero]