# Ideal Gases and Thermodynamcs

Student Learning Objectives
Lessons / Lecture Notes
Important Equations
Example Problems
Applets and Animations
Videos

Student Learning Objectives

• To understand the concpets of molecular mass, the mole, and Avogadro's number
• To understand the ideal gas law.
• To apply the ideal gas law to solve problems involving gases undergoing changes in pressure, volume, and temperature.

Lessons / Lecture Notes

PY105 Notes from Boston University (algebra-based):

HyperPhysics (calculus-based)

General Physics I notes from ETSU (calculus-based)

Important Equations

Example Problems

Problem 1
The mass density of diamond (a crystalline form of carbon) is 3500 kg/m3. How many carbon atoms per cm3 are there? (Solutions)

Problem 2
(a) In a diesel engine, the piston compresses air at 305 K to a volume that is one-sixteenth of the original volume and a pressure that is 48.5 times the original pressure. What is the temperature of the air after the compression? (Solutions)

(b) A balloon contains 2.0 liters (1 liter = 103 cm3) of nitrogen gas at a temperature of 77 K and a pressure of 101 kPa. If the temperature of the gas is allowed to increase to 23 oC and the pressure remains constant, what volume will the gas occupy? (Solutions)

Applets and Animations
 Hard Disk Gas The Hard Disk Gas model displays a two-dimensional gas made out of hard disks.  Particles are initialized with a speed v=1 in a random direction and move with constant velocity until a collision occurs. Hard Sphere Gas The Hard Sphere Gas model displays a three-dimensional (ideal) gas made out of hard disks.  Particles are initialized with a random speed and in a random direction and move with constant velocity until a collision occurs. Gas Properties Pump gas molecules to a box and see what happens as you change the volume, add or remove heat, change gravity, and more. Measure the temperature and pressure, and discover how the properties of the gas vary in relation to each other. States of Matter Watch different types of molecules form a solid, liquid, or gas. Add or remove heat and watch the phase change. Change the temperature or volume of a container and see a pressure-temperature diagram respond in real time. Relate the interaction potential to the forces between molecules. Special Processes of an Ideal Gas This applet shows different processes for an ideal gas. The user can control initial and final temperature, volume, and pressure. Reversible Reactions Watch a reaction proceed over time. How does total energy affect a reaction rate? Vary temperature, barrier height, and potential energies. Record concentrations and time in order to extract rate coefficients. Do temperature dependent studies to extract Arrhenius parameters. This simulation is best used with teacher guidance because it presents an analogy of chemical reactions. The Greenhouse Effect Just how do greenhouse gases change the climate? Select the level of atmospheric greenhouse gases during an ice age, in the year 1750, today, or some time in the future and see how the Earth's temperature changes. Add clouds or panes of glass. Galton Board A Galton board is a vertical board with n rows of pegs onto which a ball is dropped.   Each time a ball hits a peg, it has a probability p of bouncing to the left and a probability of  1-p of bouncing to the right.  The simulation's histogram shows the distribution of x-coordinates as the balls leave the board and are collected into bins.

Videos

 Download video (2.0 Mb) Watch Streaming This video shows just how strong atmospheric pressure is. The difference in pressure between the outside of the tank and the inside of the tank causes it to implode.