Work procedure

Choose the model «Изотермы реального газа» from the section «Термодинамика и молекулярная физика»

1. To take the distribution velocity histogram, carry out the following actions:

1.1. Set gas temperature in accordance with table 1.

Table 1

No
Т, ^о К

1.2. Set the velocity value onthe velocityscale displacing a mark on the graph.

1.3. To stop motion of molecules, put a cursor on the symbol on a panel and press the left mouse button. Then press button . (To introduce new values press the button «Выбор», and to begin the experiment press the button «Старт»).

1.4. Count the amount of bright molecules on the screen; velocities of these molecules will be in the interval . Do the experiment once more in items 1.2 – 1.4, changing velocity from 0 to 3000 m/s through = 200 m/s. Enter the result into table 2. Do calculations 3 times.

Table 2

vi, m/s

Δ Ni

Changing gas temperature obtain dependence of v_prob and v_sq. Enter the result into table 3.

Data processing

1. Plot the distribution histogram.

2. Plot dependences of and in coordinates

3. Determine and using obtained graphs.

Table 3

Т, К
vprob
vsq

4. Determine and using formulas (3) and (4). Compare with theoretical values.

5. Determine molecules mass and molar mass of gas using formulas (2.3) and (2.4):

6. Plot the dependence of .

Conclusions

Explain the basic peculiarities of Maxweel’s distribution.

Before doing the lab work students have to study

1. Maxweel’s distribution law of molecules velocities. Influence of temperature and mass of molecules on the type of distribution.

2. Determination and physical sense of and .

3. The method of and . determination by means of Maxweel’s distribution law

4. Give the definition of Maxweel’s distribution law of molecules velocities.

5. Deduce Maxweel’s distribution law.

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