Determination of absolute zero PDF

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Determination of absolute zero Purpose To use the relationship between the Volume of gas and temperature (Charles law) to determine the value of absolute zero by extrapolation.

Introduction Charles’ law states volume and temperature are directly proportional when pressure is constant.

Data The gas used in this experiment was methane, CH4. Total volume inside the 150 ml flask was 182.0 ml, the gas volume readings in table 1 were determined by adding the total volume of the flask and the volume dispensed by the syringe. The pressure inside the sealed flasksyringe apparatus was 1.000 atm, as measured by a pressure gauge, the pressure remained constant throughout the experiment. Table 1: Temperature (°C) and volume (ml) results of methane.

Temperature (°C) -15.0 0.0 21.5 30.0 40.0 50.0 60.0 80.0

Total volume (ml) of flask +syringe 199.35 210.87 227.7 234.05 241.76 249.5 257.2 272.65

Absolute zero calculation Using Y= 0.7714x + 210.9 derived from figure 1, where, X = temperature and y= volume, absolute zero can be determined via extrapolation. If y=0, -210.9= 0.7714xX= -210.9 /0.7714 = -273.4 °C =T0 Percentage error Using the following formula: |Experimental – actual| /actual * 100 = % Error |-273.4 °C - -273.15 °C|/ -273.15 *100 = 0.09152 % error Observation As the temperature of the water bath increased, there was a greater volume in the syringe that was occupied by the methane. This was numerically represented by differences in syringe

volume readings at different temperatures. As temperatures decreased, the volume in the syringe decreased as well.

Figure 1: Relationship between temperature (°C) and volume (ml)

Discussion The data displayed a direct linear relationship between volume and temperature, as shown by figure 1. The calculated percentage error was below 0.1 %, indicating the experiment was successful in extrapolating to find absolute zero. For future experiments, it would be interesting to see the effects of increasing and slowing rate of heating/cooling done by the water bath, on percentage error. Additionally, studying the effects of preforming the experiment with large and small initial gas volumes on the percentage error, will be informative.

Conclusion The experiment was successful as the experimental value of absolute zero was determined via extrapolation, under the conditions of Charles’ law....