ECSE 310 Thermodynamics of Computer
Homework 3
Each question has the same weight
P1) Answer the following:
1. If you open a champagne slowly, can you see “white smoke”, why?
2. Write down the state functions you have learned so far.
3. State 2nd law of thermodynamics using the language of entropy.
4. What’s reversible process/irreversible process?
5. What’s a degree of freedom?
6. State equipartition theorem, and describe the internal energy from equipartition point of view.
7. Rank average speed, most probable speed, rms speed from high to low.
8. What’s equation engraved on Boltzmann’s tombstone? Explain the equation.
P2) The speeds of 22 particles are as follows (𝑁𝑖
represents the number of particles that have speed 𝑣𝑖
):
𝑁𝑖 2 4 6 8 2
𝑣𝑖
(cm/s) 1.0 2.0 3.0 4.0 5.0
What are (a) 𝑣𝑎𝑣𝑔, (b) 𝑣𝑟𝑚𝑠 and (c) 𝑣𝑃?
P3) Suppose a container is full of oxygen gas and is kept at room temperature (300 K). Calculate the
fraction of molecules that have speeds between 599 to 601 m/s? The molar mass M of oxygen is
0.0320 kg/mol.
P4) Assume that 1.0 mol of nitrogen gas is confined to the left side of the container of the figure shown.
When the valve is opened, the volume of the gas doubles. For this irreversible process, what is the
entropy change of the gas? Assume the gas is an ideal gas.
P5) Consider a Carnot cycle that fluctuates between the temperatures 𝑇𝐻 = 850 K and 𝑇𝐿 = 300
K. It performs 1.2 kJ of work each cycle. The duration of the cycle is 0.25 s. What is the
entropy change of the working substance due to energy delivered from the hightemperature reservoir? And from the low-temperature reservoir?
P6) Construct a table like the table below for eight molecules.
Six Molecules in a Box
