GAS PROPERTIES SIMULATION
http://phet.colorado.edu/en/simulations/category/chemistry/general
You must have JAVA to run this simulation. The netbooks with orange on them
have Java, so – feel free to use one.
(Notes for users of the netbooks: set them up before class and go to the simulation. You must
make the simulation smaller than fullscreen, so that the heat control will be visible.)
PURPOSE OF ACTIVITY
You will explore the relationships between four different variables for gases. These are
pressure (P), volume (V), temperature (T), and amount of the gas in moles (n), and attempt to
explain them.
GENERAL INFORMATION
Click on the simulation entitled “Gas Properties.” Click on ‘run now.’ You will use constant
amounts in each ‘experiment.’ In each section, click on Reset. Then, pump the ‘handle’ once.
Do not pump it again. Now you have a fixed amount of gas particles. This means that the
amount of the gas is constant.
The unit for the amount of the gas is ________________, and the symbol is ____
CONSTANT TEMPERATURE
In the top right hand corner, you will see CONSTANT PARAMETERS. Click on TEMPERATURE to
set it as a constant. Record the value for PRESSURE at the standard volume in the box below
You will be varying the VOLUME. To do this, you CLICK/DRAG the handle on the left of the box.
Start with the box at the size that comes up first. Record the value for the PRESSURE at this
size, and then - when the box is largest, and when it is smallest.
(Note, when you first change the box, the temperature will change. Let the system equilibrate,
and the temperature will return to its fixed value of 300 Kelvins - near room temperature.)
PRESSURE vs VOLUME when T and n are constant
Always write the numbers with units!
STANDARD VOLUME
PRESSURE
LARGEST VOLUME
SMALLEST VOLUME
CONSTANT VOLUME
In the top right hand corner, you will see CONSTANT PARAMETERS. Click on VOLUME to set it
as a constant. Record the value for PRESSURE at the standard TEMPERATURE (300 K) in the box
below. You will be varying the TEMPERATURE. To do this, you will CLICK/DRAG the HEAT
CONTROL below the box. (If this control is not visible under the box, you will need to reduce
the size of the box, and drag down the bottom.)
PRESSURE vs TEMPERATURE when V and n are constant
Always write the numbers with units!
300 K
500 K
100 K
PRESSURE
On a cold winter morning, the tires of your car will appears to be OVER UNDER
- inflated.
CONSTANT PRESSURE
In the top right hand corner, you will see CONSTANT PARAMETERS. Click on PRESSURE to set it
as a constant. Assume that the size of the box at 300 K is NORMAL. You will be varying the
TEMPERATURE. To do this, you will CLICK/DRAG the HEAT CONTROL below the box. Does the
volume of the box get larger or smaller at the temperatures listed? (NOTE: if the box is very
big, at 300 K, click Reset, and pump in a smaller amount of gas.)
VOLUME vs TEMPERATURE when P and n are constant
CIRCLE TERM OF SMALL, NORMAL, LARGE!
Volume
300 K
400 K
NORMAL
SMALL NORMAL LARGE
100 K
SMALL NORMAL LARGE
Fill in this table.
CONSTANTS VARIABLES RELATIONSHIP BETWEEN THEM
DIRECT
INVERSE
DIRECT
INVERSE
DIRECT
INVERSE
PROBLEMS
1. You have a sealed box with air in it at a temperature of 25°C and 1.0 atm. You heat the box.
The pressure INCREASES DECREASES Explain your answer scientifically.
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2. Weather balloons are made of a flexible material. A weather balloon of a volume of 400
liters is released, and rises up to 15,000 feet. The balloon will become LARGER SMALLER.
Explain your answer scientifically.
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