What is the Ideal Gas Law

If you are a high school or college chemistry student, you are no doubt aware of the Ideal Gas Law. In fact, it is likely that this equation has given you nightmares and cold sweats as you think about what variable goes where. The Ideal Gas Law is a very powerful tool when dealing with pressures and temperatures of gases. It approximates how a gas will react under certain circumstances.

First, let’s take a look at the equation that makes up the Ideal Gas Law. The equation is actually a combination of Charles’s and Boyle’s Laws of gases. I’ll spare you the derivations of the laws, as they are mostly a lot of mathematics.

The equation is pV=nRT. p is the pressure of the gas. V is the volume. n is the amount of the gas (in moles). R is a constant – always the same number (the reasons this factor is included are difficult to explain without going in to a very detailed chemistry lesson). Lastly, T is the temperature of the gas.

The Ideal Gas Law equation is very useful in a variety of circumstances. By mainipulating the equation, you can determine how the pressure of a gas will change if you increase the temperature. Or you can figure how the temperature will change if you change the pressure. In addition, you can calculation the effects on volume if you change temperature or pressure.

These calculations are very important to the science of thermodynamics. The implications of these equations are far reaching and vital to many engineering projects. You can’t run a steam engine without understanding these rules. Even nuclear reactors operate under the rules outlined in the Ideal Gas Law. Thermodynamics is a huge area of modern science.

There are some limitations to the Ideal Gas Law. It does not take in to account molecular interactions or molecular size of the constituents of the gas. Because of this, it is really just an approximation under most circumstances – albeit a very accurate approximation.

Because molecular size and the interactions between molecules are less important at low pressures, the Ideal Gas Law is more accurate at low pressures and low temperatures. In very exotic environments where the pressure of a gas system is very high, the equation breaks down and must be replaced with something that has a few more complicating factors involved.

The Ideal Gas Law is not something the average person is going to need in their lives, even if they make a living filling Helium balloons. Despite this, the implications of the equation are massive. Much of our modern understanding of gases and thermodynamics is contained within that simple equation.