1. Take a gas piston from the Glassware shelf and place it on the workbench.
4. Remove the gas piston from the balance.
6. Take a thermometer and pressure gauge from the Tools shelf and drop them on the gas piston.
7. Take a heating plate from the Tools shelf and drop it on the gas piston.
10. Once the temperature of the gas has reached nearly 200C, remove the piston from the heating plate.
11. The temperature will begin to fall and the gas volume displayed in the Data window will decrease. Record pairs of temperature and volume data every 10 degrees C or so, until the temperature has returned to room temperature.
Temperatures Gas Volume
NOTE: This is best accomplished by working in pairs, with one person calling out the data values and the other writing them down.
12. Next, take a constant temperature bath from the Tools shelf and place it on the workbench.
13. Using the Properties window, set the bath to dry ice.
14. Drag the bath and drop it onto the gas piston.
Temperature Gas Volume
1. Record the formula of the gas you selected to run the experiment.
3. The molecular weight of the gas is shown in the Data window. Calculate the number of moles of gas from the measured masses of the empty piston and the piston plus gas.
4. Use a spreadsheet to construct a graph of the recorded data with the temperature, in degrees C, on the x-axis and the volume, in mL, on the y-axis.
5. Find the slope and intercept of the straight line fit to the data points. In Excel, the slope is given by the function SLOPE (y values, x values) and the intercept is given by the function INTERCEPT (y values, x values). Record these values.
T0 = -(intercept / slope)
7. The accepted value for absolute zero is -273.15C. Calculate the percent error of your results according to:
%error = |T(experimental) - T(accepted)| / |T(accepted)| * 100
8. In designing the experimental procedure, should you aim to use a large or small initial volume of air? Explain why.
9. In designing the experimental procedure, should you try to control the heating/cooling rate of the apparatus to be slow or fast? Explain why.
10. This experiment extrapolates the behavior of an ideal gas down to coldest possible range. In reality, the gas would condense into a liquid as it approaches absolute zero. Does this affect the conclusion reached regarding the value of absolute zero?
11. Amazingly enough, researchers have recently been able to cool a low-density gas of sodium to nano-Kelvin temperatures, and -273.15C is indeed the limit that is approached. At these low temperatures, the gas is dominated by quantum mechanical effects.
Experimental Data obatined from a real practical lab is maniplated and used in order to extract key information about absolute zero. Other questions are also answered regarding ideal gases and absolute zero.