Open the page here in a new window to do the following:

1. Scroll down to the download site for ATOMDEMO listed under the title Where can I get it? Click on the first link and save the program to your PC.
2. Continue scrolling down to the section titled Phases of matter and diffusion and read it. Also read the definitions at the end of this assignment.
3. Run the program ATOMDEMO.EXE and immediately set the temperature to 0 K. What is this temperature called? What do you notice about the motion of the particles?
4. Raise the temperature to 50 K. What is this temperature in the Celsius scale? What has changed in the motion of the particles?
5. Continue to raise the temperature slowly and note the way in which the particle motion changes. Describe it in words.
6. What is the melting point of the substance? How do you know?
7. What is the boiling point of the substance? How do you know?
8. Set the temperature midway between the melting and boiling points. What phase is the substance in? Are all the particles in this phase? Explain. (Hint: read about vapor pressure below.) What do you notice about the position of the green atom relative to the other atoms?
9. Now, set the temperature below the melting point. What phase is the substance in? Are all the particles in this phase? What do you notice now about the position of the green atom relative to the other atoms? How does this compare to what you saw in the previous question?
10. Now, set the temperature above the boiling point. What phase is the substance in? Are all the particles in this phase? What do you notice now about the position of the green atom relative to the other atoms? How does this compare to what you saw in the previous questions?
11. Type the answers to questions (3 to 10) in an e-mail with the subject line reading "Asst 3 Chem 11" and send it to [email protected]. If the system is slow you can write the answers on a sheet of paper to hand in. One assignment per person.

Definitions

Absolute zero: temperature at which atomic motion, and hence heat, are at their minimum allowable values within the limits of quantum mechanics.
Boiling point (also know as condensation point and vaporization point): temperature at which a substance undergoes the phase change from liquid to gas.
Kelvin scale: temperature scale in which the lowest temperature possible is 0 degrees (0 K, also known as absolute zero) but where the increment of one degree is the same amount as in the Celsius scale. 0 K is the same as -273.15^o C so the equation relating the two scales is:
T_Kelvin = T_Celsius + 273.15
Melting point (also known as freezing point): temperature at which a substance undergoes the phase change from solid to liquid.
Vapor pressure: the pressure due to gas molecules that have escaped from the surface of a liquid substance. Vapor pressure for a given substance is determined by the temperature of the substance alone. The vapor pressure rises with temperature and the boiling point occurs when the vapor pressure is equal to the ambient pressure.