DETERMINATION OF GAS SPECIFIC HEAT CAPACITIES RELATIONSHIP

Task 1. Measurement of the liquid levels difference in the manometer tubes h₁

1.1. Open the tap 3 and close it when the levels of the liquid in both manometer tubes are the same.

1.2. Open the tap 4 and carefully pump some air into the vessel. Stop pumping and close the tap 4 when the difference between the liquid levels reaches 150 – 200 mm.

1.3. Wait for 3—5 minutes, until the difference between levels stops changing. Count the difference between the manometer levels h₁.

Enter the results into table 1.

Task 2. Measurement of the liquid levels difference in the manometer tubes h₂

2.1. Open the tap 3 and again quickly close it in that moment when the liquid levels in manometer tubes are the same.

2.2. Wait 3—5 minutes, when position of liquid levels in manometer stop changing count the difference between the manometer levels h₂

2.3. Repeat 5 times measurements according to items 1.1—2.2.

Enter the results of h₁ and h₂ into table 1.

Table 1

Exp. No	Liquid level h1, mm	Liquid level h2, mm	Adiabatic exponent g	Average value of adiabatic exponent	Deviation from mean value	Absolute error

Task 3. Calculate value of adiabatic exponent and measurement error.

3.1. Calculate adiabatic exponent according to the formula:

Enter the results into table 1.

3.2. Calculate the error of adiabatic exponent determination.

Calculate mean value according to the formula:

where n = 5 is amount of measurements

Enter the results into table 1.

3.3. Determine deviation from mean value according to the formula:

Enter the results into table 1.

3.4. Calculate root-mean-square deviation according to the formula:

= .

3.5. Determine the absolute error of measurements according to the formula:

where the Student’s coefficient is t_St = 2,78 (n = 5 and a = 0,95)

Fulfill calculation for four significant digits.

Enter the results into table 1.

Conclusions

The data of laboratory work fulfillment

Pass mark Signature

Mark of laboratory work defending Signature

questions to be admitted for doing laboratory work
and its defending

1. Write down equation of state for perful gas. Explain its sense.

2. What is physical sense of internal energy of perfect gas?

3. What is physical sense of Universal gas constant?

4. Formulate the first law of thermodynamics and apply it for isoprocess of perfect gas.

5. Give definition, write down equation and draw graphs of isohoric and isobaric proces­ses of perfect gas.

6. What is called adiabatic process?

7. What is body heat capacity? What does heat capacity depend on?

8. What types of body heat capacities do you know?

9. What is bigger С_Р or С_v? Explain your answer.

10. How is the heat capacity С_Р and С_v determined in accordance to molecular-kinetic theory?

11. Perfect gas heat capacity at adiabatic and isothermal process.

12. What is the number of degrees of molecule freedom?

13. Deduce the formula for adiabatic exponent calculation.

14. Deduce the formula for adiabatic exponent calculation by experimental method.

LABORATORY WORK

Date: 2015-01-12; view: 1021