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Gas Laws 2
Introduction to the Gas Laws (continued from page 1)
Page 1
Introduction to the Gas Laws
Introduction to the Gas Laws
Page 1
Introduction to the Gas Laws
Introduction to the Gas Laws
Page 2
Introduction to the Gas Laws
Introduction to the Gas Laws
Page 2
Introduction to the Gas Laws
Introduction to the Gas Laws
Page 3
The Flow of Gases in Leaks
The Flow of Gases in Leaks
Page 3
The Flow of Gases in Leaks
The Flow of Gases in Leaks
Page 4
The Flow of Gases in Leaks
The Flow of Gases in Leaks
Page 4
The Flow of Gases in Leaks
The Flow of Gases in Leaks
Page 5
The Flow of Gases in Leaks
The Flow of Gases in Leaks
Page 5
The Flow of Gases in Leaks
The Flow of Gases in Leaks
Page 6
Connections to other Leak Test Adresses
Connections to other Leak Test Adresses
Page 6
Connections to other Leak Test Adresses
Connections to other Leak Test Adresses
Page 7
Helium Leak Test on Heat Exchangers
Helium Leak Test on Heat Exchangers
Page 7
Helium Leak Test on Heat Exchangers
Helium Leak Test on Heat Exchangers
Page 9
Leak Detection with Tracer Gas Methods
Leak Detection with Tracer Gas Methods
Page 9
Leak Detection with Tracer Gas Methods
Leak Detection with Tracer Gas Methods
Page 10
Leak Test with Laser Beam
Leak Test with Laser Beam
Page 10
Leak Test with Laser Beam
Leak Test with Laser Beam
Page 11
The Download Page
The Download Page
Page 11
The Download Page
The Download Page
Page 12
Literature
Literature
Page 12
Literature
Literature
Page 8
Leak Detection and
Measuring Methods
Leak Detection and
Measuring Methods
Page 8
Leak Detection and
Measuring Methods
Leak Detection and
Measuring Methods
17.) Boyles Law
17.) Boyles Law
18.) Charles´ Law
18.) Charles´ Law
19.) The Law of Gay Lussac
19.) The Law of Gay Lussac
The absolute Scale of Temperature
The absolute Scale of Temperature
20.) The Universal Gas Law
20.) The Universal Gas Law
21.) The Universal Gas Constant
21.) The Universal Gas Constant
22.) The individual Gas Constant
22.) The individual Gas Constant
23.) Individual Gas Constants of some Gases
23.) Individual Gas Constants of some Gases
24.) The Greek Alphabet
24.) The Greek Alphabet
17.) Boyles Law.
When the volume of a gas is decreased (for example by a piston), the pressure increases in the same ratio, if the temperature does not change. Compressing the volume to a half of its size doubles the pressure.
1
1
2
2
also well known as:
When a vacuum is produced and the pressure is decreased by a large amount, the gases expand to very large volumes. This occurs also with contamination on the inner walls of the vacuum chamber, which evaporates (for example fingerprints).
with equal numbers of molecules (temperature kept constant)
18.) Charles` Law.
The volume of a gas changes with temperature if the pressure is kept constant. When the gas becomes colder, the volume decreases. As it becomes warmer, the gas expands.
T in Kelvin (see scale of absolute temperature below).
When the temperature doubles, the volume increases similarily by the factor of 2, provided that the pressure stays constant.
with equal numbers of molecules and constant pressure
With a closer look at Charles` law, one can find a more detailed relationship between temperature and volume, known as the law of Gay-Lussac:
19.) The Law of Gay-Lussac:
When the temperature of a gas changes from 0...C by one degree, the volume changes by 1/273 of the original value:
0
or
From this law, Lord Kelvin founded the absolute scale for the temperature, in which 0 Kelvin = absolute zero = 273.15 degrees Celsius.
Thermodynamic
Temperature T in Kelvin [K]
Temperature T in Kelvin [K]
Celsius Temperature in [..C]
373.15
100
273.15
0
263.15
-10
10
-263.15
0
-273.15
0
Boyles Law
describes the relationship between volume and pressure, where temperature and mass (number of particles) must stay constant.
Charles` Law
describes the relationship between volume and temperature, where pressure and mass stay constant.
Avogadro´s Law
describes the relationship between volume and mass, where temperature and pressure stay constant.
The above three law´s combine to give the universal gas law:
20.) The Universal Gas Law.
... ( Greek Ny) is the symbol for the quantity in mol or kmol.
The universal gas law is not restricted like Charles´, Boyle´s and Avogadro´s laws.
The temperatures in Charles law and in the universal gas law are inserted as absolute temperatures in Kelvin.
The temperatures in Charles law and in the universal gas law are inserted as absolute temperatures in Kelvin.
p
=
pressure
N/m..
Pa (1 bar = 10. Pascal).
V
=
volume
m..
cubic metre
T
=
temperature
K
Kelvin
=
quantity
mol
R
=
universal gas constant
2
5
3
21.) The Universal Gas Constant.
For calculations, the following, equivalent values are often used:
R =
83.14 mbar x l x mol..x K..
R =
8.314 x 10..mbar x l x kmol...x K..
R =
8.314 x 10..x Pam..x kmol..x K...
-1
-1
-1
-1
4
-1
-1
3
3
22.) The Individual Gas Constant.
If the universal gas constant is divided by the relative mass number (M) of the molecule of the gas in question, the result is the individual gas constant Ri for this gas.
23.) Individual gas constants for some gases (J/kg x K)
Gas
Ri
Air
287
Argon
208
Helium
2079
Hydrogen
4116
Nitrogen
297
Oxygen
260
Water vapour
461
R-12
68.7
R-22
96.1
If many calculations are made for the same gas, it is often easier to use the individual gas constant Ri
24.) The Greek Alphabet.
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