Constant-Volume Gas Thermometer PDF

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Summary

Constant-Volume Gas Thermometer...

Description

The Constant-Volume Gas Thermometer* and the Absolute Temperature Scale Scale

Calibration: Place the flask in an ice-water bath, and raise or lower the mercury column B until the gas is at its original volume say 0 on the scale.

𝑝𝑎

2

h

3

0

 p gas , 0 C  p a  gh0 C

1

Repeat with a boiling bath, and raise height of column B until to get the same volume of gas.

B

Gas

Mercury

𝑝𝑔𝑎𝑠

 p gas ,100  C  p a  gh100  C

Flexible hose T to be measured P (Pa)

To measure the temperature of a substance, the flask is placed in thermal contact with the substance. Then, we have the gas pressure ps , and the temperature of the substance Ts is interpolated from the graph.

Ps

Ts T (C)

0 C

Using different volumes of dilute gas, we find that al rapolate back mperature T = –273.15 C, where the pressure inside the thermometer is zero. This temperature is called absolute zero. TK  TC  273 .15 p (Pa)

273.15 C

0 C

100 C

T (C) T (K)

0K (lower limit) Note:

273.15 K

Temperature difference, T:

1 C = 1 K = 1.8 (=180/100) F

Temperature, T:

5 TC  TK  TF 9 1 C  1 K; 1 C = 274.15 K

(no upper limit ) [TC = TK]

[TC  TK ]...