1 Which of the below substances, at the same temperature, most likely has the most entropy?
A) MgO (s) B) Hg (l) C) He (g) D) Na (s)
2 Ar(g) or Xe(g): Choose the substance having the larger standard entropy value at 25 deg-C. The same molar amount (N) is used in the comparison. Explain the basis for your choice.
Video on the 2nd law of thermodynamics, thermal, mechanical and chemical equilibrium.
Video on the thermodynamic identity, heat and work, 1st and 3rd laws, entropy of the Einstein crystal and the ideal gas and a new derivation of the ideal gas EOS.
Repeat of 2 questions from lecture 6
3 Free expansion of a gas. A gas is confined to the left half of a thermally-isolated container, the right hand side is empty. Suddenly, the partition breaks and the gas fills the whole container.
The internal energy U of the gas
A) increases B) decreases C) remains constant
4 Did the entropy of the gas change?
A) yes, entropy increased B) Yes, entropy decreased C) No, there was no change in entropy
Video on applications on the ideal gas
5 Quasi-static, isothermal expansion. A gas is allowed to slowly expand at constant temperature to twice its original volume.
The internal energy U of the gas
A) increases B) decreases C) remains constant
6 Did heat enter or leave the gas during this process?
A) heat entered B) heat left C) no heat was transferred during this process
7 Is the final entropy of the gas in this case (isothermal expansion), the same or different than the final entropy of the gas in the case of free expansion.
A) same B) different
8 Why does the valve on a bicycle pump get hot when you are pumping a tire? Is it because of friction from the air being forced through the valve? What happens to the temperature of your valve if you use a cartridge of compressed CO2 to inflate your tyre? (from "The flying circus of physics" 3.16)
9 Have you ever noticed the thin fog that gathers at the mouth of a chilled champagne or soda bottle just after it's been opened? What causes the fog? (from "The flying circus of physics" 3.19)