The ideal gas law, PV=nRT or PV=NkT, describes the behavior of a hypothetical gas that does not interact with other gases. It can be used to determine unknown properties of ideal gases, but only works in theoretical situations. The law is taught in high school and college chemistry classes to illustrate important concepts on gas behavior.
The ideal gas law is an equation used in chemistry to describe the behavior of an “ideal gas,” a hypothetical gaseous substance that moves randomly and does not interact with other gases. The equation is formulated as PV=nRT, which means that pressure times volume equals the number of moles times the ideal gas constant times temperature. The ideal gas law is generally used with the SI system of units, so P is in Pascals, V is in cubic meters, n is dimensionless and represents the number of moles, R is in joules divided by kelvins times moles, and T is in Kelvin. The law can also be given as PV=NkT, with the number of particles (N) replacing the number of moles and Boltzmann’s constant replacing the ideal gas constant.
An important element that those working with the ideal gas law need to understand is that it only works in idealized and theoretical situations. Real gases interact with each other and with themselves to varying degrees, and such interactions detract from the randomness of gas particle motion. At low temperatures and high pressures, for example, the forces of attraction between gases can significantly alter the way gases behave. At sufficiently low temperatures and high pressures, many gases even become liquids, but the ideal gas law does not account for this behavior.
There are a variety of uses for the ideal gas law, but they almost always involve theoretical situations. One can use the ideal gas law to determine any of the unknown properties of an ideal gas, assuming that the rest of the properties are known. For example, if the pressure, the number of moles, and the temperature are known, the volume can be calculated using simple algebra. In some cases, the ideal gas law can be used in real situations, but only with gases whose behaviors closely follow the law under certain conditions of temperature and pressure, and even then it can only be used as an approximation.
The ideal gas law is usually taught in detail in high school and college general chemistry classes. Students use the law to learn the basics of calculus in chemistry and are often required to do several unit conversions before actually applying the equation. The law also illustrates some important concepts on the behavior of gases. It shows, for example, that an increase in the pressure of a gaseous system tends to correspond to a decrease in volume, and vice versa. It is important to understand the relationships demonstrated, even though the equation cannot be used for precise calculations on real gaseous systems.
Protect your devices with Threat Protection by NordVPN
