Part 2. Constant Volume.
Vary the temperature from 300 to 900 K by using the heat option. Record the Pressure and Temperature for at least 6 different temperatures in the 300 to 900 K range. Each time you heat up the gas you must wait for about 20 to 30 seconds before things settle down. Graph these values on the graph provided. Here’s another short youtube video with a few tricks related to this activity. Here’s and Excel file that makes it easy to calculate the average and standard deviation of 5 or 6 pressure readings.
Table 1.
Use: http://www.atmosedu.com/physlets/SeaFloorSpreading/G1.htm to help you make a graph and then use a screen capture of that window to copy and paste your graph below. If you resize the window so that just the graph appears then you can paste the screen capture directly below without editing it. Otherwise you can paste it into a paint program, trim it up, and then copy and paste that image below.
Paste Graph 1 here
• What is the relationship between pressure and temperature at constant volume?
• Using this data, predict at what temperature the pressure will become:
0.20 atm predicted temperature =__________________________
0.1 atm predicted temperature =__________________________
0 atm predicted temperature =__________________________
Remove heat from the chamber to get back to near 300 K with the fixed volume. The easiest way to do this is click the reset button, select constant volume, and add 100 heavy molecules back into the container. The default setting is that all new molecules go into the container at a temperature of 300K.
Part 3. Constant Temperature.
Select Ruler from the measurement tools and use it to measure the volume of the gas in relative units.
In the image below the ruler is measuring the volume to be 6.6 relative units.
Vary the volume by sliding the left wall to the right or left and record at least 6 different Volume Pressure pairs. Each time change the volume you must wait for about 20 to 30 seconds before things settle down. Record the Volume Pressure pairs in the table below and then graph these values on the graph provided.
Table 2.
Use: http://www.atmosedu.com/physlets/SeaFloorSpreading/G2.htm to help you make a graph and then use a screen capture of that window to copy and paste your graph below.
Paste Graph 2 here
• What is the relationship between pressure and Volume at constant Temperature?
• Using this data, predict at what Volume the pressure will become:
3.00 atm predicted volume =__________________________
0.1 atm predicted volume =__________________________
Although the temperature readjusts to 300 K when constant temperature is selected, the temperature does change a bit when the volume changes.
Does the temperature increase or decrease when the volume increases?
Does the temperature increase or decrease when the volume decreases?
The density is the mass or number of molecules per unit volume
Using 100 for the Number of molecules calculate the relative density for the volumes in Table 2. Record these values in Table 3 below and then graph these values on the graph provided. Here’s an online calculator for easy use.
Table 3.
Use: http://www.atmosedu.com/physlets/SeaFloorSpreading/G3.htm to help you make a graph and then use a screen capture of that window to copy and paste your graph in a little bit below. (keep the Graph 3 window open as you will add to it shortly).
• What is the relationship between pressure and Density at constant Temperature?
Paste your final version of Graph 3 here
Part 4. Constant Pressure
Reset the number of molecules to 100 and keep the constant temperature setting selected until the temperature settles back to 300 K for a relative volume around 6.6.
Table 4.
Use: http://www.atmosedu.com/physlets/SeaFloorSpreading/G4.htm to help you make a graph and then use a screen capture of that window to copy and paste your graph below.
Paste Graph 4 here
• What is the relationship between Volume and Temperature at constant Pressure?
• Using this data, predict at what Temperature the volume will become :
10 Volume units predicted temperature =__________________________
1.0 Volume units predicted temperature =__________________________
When a parcel of air is heated up near the surface it expands but its pressure stays constant because the weight of air from above stays the same. As the temperature of the parcel increases the density _______________ [lower or higher] and the air parcel ______________ [rises or sinks].