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Gases are difficult to understand. They are densely packed with billions and billions of highly energetic gas molecules that are capable of colliding and possibly interacting with one another. Because it is difficult to precisely describe the behaviour of a real gas, the concept of an Ideal gas was developed as an approximation that can be used to model and predict the behaviour of real gases.
Ideal Gas
The molecules of an ideal gas do not attract or repel one another. The only interaction between ideal gas molecules would be an elastic collision when they collide with each other or an elastic collision when they collide with the container’s walls, whichever occurs first.
The molecules of an ideal gas take up absolutely no space. The gas takes up volume because the molecules spread out over a large area of space, but the molecules of an Ideal gas are approximated as point particles that have no volume in and of themselves.
However, while there are no gases that are perfectly ideal, there are plenty of gases that are close enough to an ideal gas gas to make the concept of an ideal gas a very useful approximation in a wide range of situations. For many of the gases that we are interested in, temperatures near room temperature and pressures near atmospheric pressure are very close to being ideal conditions.
There can be significant deviations from the ideal gas law if the pressure of the gas is too high (for example, hundreds of times greater than atmospheric pressure) or the temperature is too low.
What exactly is the Ideal Gas Law?
The ideal gas law, also known as the general gas equation, is a state equation for a hypothetical ideal gas that can be expressed mathematically. Despite the fact that the ideal gas law has a number of limitations, it is a good approximation of the behaviour of many gases under a variety of circumstances. According to Benoît Paul Émile Clapeyron, the ideal gas law was first stated in 1834. It is a combination of the empirical Charles’s law, Boyle’s law, Avogadro’s law, Gay-law, Lussac’s and Avogadro’s law, among other things.
The Ideal Gas Equation
Four parameters of a gas are known as gas variables. These parameters are: pressure (P), volume (V), number of molecules of gas (n), and temperature (T). In addition, the constant R is included in the equation shown below, which is known as the gas constant, and will be discussed in greater depth later:
PV=nRT
PV/nRT = 1
Known as the compression factor, this term is a measure of the ideality of the gas in which it is applied. When this equation is applied to an ideal gas, the result will always be 1. A gas will behave more like a real gas rather than an ideal gas to the extent that it deviates from the number 1. When working with this equation, there are a few things that should always be kept in mind, as you may find it extremely useful when checking your answer after solving a gas problem.
The number of molecules and the temperature are directly proportional to the pressure. (Because P is on the other side of the equation from n and T, this is true)
Pressure, on the other hand, is inversely proportional to the volume of the container. (Because P is on the same side of the equation as V, this is true.)
Ideal Gas Law Units
Once the gas constant R = 8.31 J/K.mol has been determined, the pressure P (in pascals Pa), the volume V (in m3), and the temperature T (in kelvin K) must all be entered into the equation.
When we use the gas constant R = 0.082 L.atm/K.mol, the pressure should be expressed in atmospheres atm, the volume should be expressed in litres L, and the temperature should be expressed in degrees Kelvin K.
Relationship between Pressure and Temperature
When we extrapolate the Pressure and Temperature graph, we see that no matter which gas we are graphing, the graphs always intersect the x-axis at a point that we have designated as the absolute zero. This point represents the beginning of the Kelvin scale, which is represented by the letter K. In the Celsius scale, zero degrees Kelvin is equivalent to -273.5 degrees Celsius. This is the coldest temperature that can be achieved. As a molecule becomes colder, its energy decreases, and as a result, the amplitude of its movement and vibrations decreases. With continued cooling, the atom will eventually reach a state of minimum internal energy, in which it has lost almost all of its energy and has become stationary in its orbit.
Conclusion
Known also as the general gas equation, the ideal gas law describes how a hypothetical ideal gas behaves in terms of its equation of state. The model is a good approximation of the behaviour of many gases under a wide range of conditions, despite the fact that it has some limitations. Clapeyron’s law was first stated in 1834 as a combination of the empirical Boyle’s law, Charles law, Avogadro’s law, and Gay-law, Lussac’s and it has been in use ever since.
