What is the gas constant?
The gas constant (represented by the letter R), also known as the ideal gaseous constant, is the function of the pressure (P), volume (V), temperature (t) and gas moths (N) in the stoichiometric equation. The PV = NRT equation is known as an ideal gas law. The value r can be detected by eating equation for reading R = (PV) / (NT). In other words, the gaseous constant is multiplied by its volume, divided by the number of gas moths multiplied by its temperature in Kelvins.
The ideal gases are hypothetical - strictly adhere to all simple gas laws and have a molar volume of 22.4141 liters at standard temperature and pressure (STP), which is 273 Kelvin, 1 atmosphere. In STP, however, most gases behave like ideal gases, so the value R is generally 0.0821 l atm / mol K or 8.3145 J / MOL K. For example, the law of the ideal gas and the gas constant can be used to find a pressure of 0.508 mol oxygen in a 15 -liter container. It calls, temperature and number of moths are known.
things change when gas is at low temperature or under high pressure. Under these conditions, gas molecules move closer together and slower, so the intermolecular forces, called van der waals, cause the measured pressure to be lower than expected. When the molecules are closer to each other, the volume of real molecules also becomes a higher fraction of the total gas volume.
In order to compensate for the behavior of the real gases, the van der Waals equation comes into play. Expression (n
2 a)/V
2
compensates for intermolecular forces of attraction and NB expression compensates for the volume of gas molecules. Together these terms are the equation of van der waals:[P + (N
2 A)/V
expressions n 2 and nb are called van der waals constants and must be determined experimentally. The Van der Waals equation is only necessary when the gas is at high temperature or low pressure. If the gas is at a room temperature or above the roomA temperature and at pressure less than a few atmosphere, an ideal gas law would apply.