Difference between revisions of "Ideal Gas Law"

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m (See also; external reference.)
 
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The ideal gas law, or universal gas equation, is an equation of state of an ideal gas. It combines several gas laws (i.e., [[Dalton’s Law]], [[Boyle’s Law]], [[Charles Laws]]):  
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The '''ideal gas law''', is an equation of state for an ideal gas. It combines three [[gas]] laws ([[Dalton's Law of Partial Pressures|Dalton's Law]], [[Boyle's Law]] and [[Charles' Law]]) into one equation:  
  
PV = nRT
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:<math>PV = nRT</math>
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where
 
   
 
   
P is the pressure of gas in pascals;  
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*<math>P</math> is the [[pressure]] of gas;
V the volume it occupies in cubic meters;  
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*<math>V</math> the [[volume]] the gas occupies;
T the temperature of the gas in degrees Kelvin;  
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*<math>T</math> the absolute [[temperature]] (meaning it must be in [[Kelvin]] or [[Rankine]]);
n is the molar mass of the gas occupying the volume V;  
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*<math>n</math> is the number of [[Mole (chemistry)|moles]] of the gas;
R is the gas constant  
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*<math>R</math> is the ideal gas constant.
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It can also be expressed in terms of the number of [[molecules]], <math>N</math> and the Boltzmann constant, <math>k_B</math> as:
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:<math>PV = N k_B T</math>
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The ideal gas constant can be expressed in any number of units, but the most common representations are <math>0.0821\,L \cdot atm \cdot mole^{-1} \cdot K^{-1}</math> or <math>8.314\,J \cdot mole^{-1} \cdot K^{-1}</math>
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==Ideal Gas==
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The equation is valid only for an ideal gas, the hypothetically perfect embodiment of a gas in which the particles ([[atom]]s or [[molecule]]s) in the gas are point particles (have no [[volume]]) and experience no intermolecular forces. All collisions between the particles or the particles and the container are perfectly elastic. 
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Since this is just a model, real gases only obey the ideal gas law approximately, not perfectly. Generally, the ideal gas assumption is accurate for unreactive gases at high temperature and/or low pressure. A good rule of thumb is that the assumption can be used above room temperature and below 1 [[atmosphere]] of pressure.
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==Density==
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With the molar mass (''M''), the ideal gas law can be used to calculate the [[density]] of a gas, <math>\rho</math>.
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:<math>PM= \rho RT</math>
  
R = 0.0821 <math>\frac{L \cdot atm}{mole \cdot K}</math> or 8.314 <math>\frac{J}{mole \cdot K}</math>
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==See also==
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*[https://en.wikiversity.org/wiki/Ideal_gas_law Ideal Gas Law]
  
The equation is valid only for an ideal gas. Real gases obey this equation only approximately, but its validity increases as the density of the gas tends to zero.
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[[Category:Physics]]
[[category:physics]]
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[[Category:Thermodynamics]]
[[category:chemistry]]
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[[Category:Chemistry Laws and Principles]]

Latest revision as of 21:51, 15 January 2017

The ideal gas law, is an equation of state for an ideal gas. It combines three gas laws (Dalton's Law, Boyle's Law and Charles' Law) into one equation:

where

It can also be expressed in terms of the number of molecules, and the Boltzmann constant, as:

The ideal gas constant can be expressed in any number of units, but the most common representations are or

Ideal Gas

The equation is valid only for an ideal gas, the hypothetically perfect embodiment of a gas in which the particles (atoms or molecules) in the gas are point particles (have no volume) and experience no intermolecular forces. All collisions between the particles or the particles and the container are perfectly elastic.

Since this is just a model, real gases only obey the ideal gas law approximately, not perfectly. Generally, the ideal gas assumption is accurate for unreactive gases at high temperature and/or low pressure. A good rule of thumb is that the assumption can be used above room temperature and below 1 atmosphere of pressure.

Density

With the molar mass (M), the ideal gas law can be used to calculate the density of a gas, .

See also