We all are surrounded by gases. In fact, the air we breathe in is a mixture of gases. Ideal Gas Law helps in understanding the behavior of gases and is thus very useful in designing gas-based applications.
Ideal gas law is the combination of three gas laws (Boyle’s law, Charles, and Avogadro’s law). Boyle’s law states that the pressure of a gas at a fixed temperature is inversely proportional to its volume. Charles’s law states that the volume of a gas at constant pressure is directly proportional to temperature. Whereas, Avogadro’s law states that gases with equal volumes have the same number of molecules at constant pressure.
If we combine these three gas laws, we get the Ideal Gas Law. It is a comprehensive law that simultaneously explains the relationship between four gas variables i.e. Temperature, Pressure, Volume, and Number of moles. The mathematical form of this law is PV= nRT.
Since it is one of the most important laws in Chemistry, as an educator, you will probably have to teach it in an introductory chemistry course. For some students, this law is hard and boring unless you adopt some interesting strategies.
Read on to learn 3 reasons why ideal gas law can be trickier for students and 5 ways to make it an easy-to-understand topic for students.
First, let's explore the three reasons why the ideal gas law can be hard, even for the most diligent students.
Generally, the laws feel abstract to students. For them, these laws are just some statements that are to be memorized for exams. Since gas molecules are microscopic and can’t be visually seen, it becomes hard for them to visualize the behavior of gases.
In chemistry and general sciences, we deal with ideal conditions that actually don’t exist in the world. The concept of an ideal gas is also theoretical. Since no ideal gas exists, students fail to understand the relevance of this law in the context of the contemporary world, which again results in a loss of interest in the content being taught.
Like other Chemistry laws, this law is also expressed in terms of a mathematical expression. Since multiple variables like Pressure, Temperature, and Volume are involved, students get confused about their relationship.
Keeping in view some of the problems that students may face when studying the ideal gas, here are five ways through which you can make ideal gas law a fun and exciting topic for students.
When teaching dry and abstract concepts like Ideal Gas law, one of the best ways to get students’ attention is by telling them a story surrounding that concept. You can either explain how the process was discovered or tell about the people who created it and what experiment led them towards it. You can mention some interesting stories about Robert Boyles, Jacques Charles, and Emile Clapeyro.
Robert Boyle: The Man Behind Boyle’s Law
The first gas law was stated by Robert Boyle, an Irish Philosopher, and thinker. At that time, since science was not categorized as a branch, scientists emphasized reasoning and presenting their ideas to gain knowledge. They were called natural philosophers rather than scientists. Moreover, the emphasis was on thinking rather than observation or experimentation.
Boyle, in contrast to many of his contemporaries, did not subscribe to the Aristotelian school of thought. Instead, he believed that the only way for scientists to gather information about the world was via the careful observation of phenomena and the performance of experiments. He was one of the first scientists to conduct experiments, and together with other scientists working at the time, he revolutionized the way scientists do research and create discoveries. It was one of his experiments on air pumps that led him to present the relationship between pressure and volume of the gas. The discovery is known to us as Boyle’s law.
The story of Jacques Charles is also quite similar. He studied Boyle’s work on gases and came up with the thought of building weather balloons with hydrogen. In 1783, Charles and Robert brothers tested the world’s first hydrogen balloon. It was a small balloon that just could lift 9 kg of weight; the balloon flew in the air for about 45 minutes.
A few years later, he took five balloons of equal volumes filled with different gases. He raised the temperature of each balloon and found out that the volume also increased. As a result, he concluded that the volume of a gas at fixed pressure is proportional to the temperature.
Emile Clapeyro: The Man Who Proposed Ideal Gas Law
Later when chemical studies became more complex with the concepts of atoms, molecules, and elements, multiple scientists including Joseph Gay-Lussac, and Avogadro presented their theories on the number of gases.
Finally, in 1834, Emile Clapeyro was the first one who combined all these gas laws and form a single law that simultaneously explains the relationship between temperature, pressure, volume, and no. of moles of the gas. Clapeyro just combined the variables presented in all of the laws and presented them in a single law, which we know today as the Ideal Gas Law.
Students have a lot of misconceptions about an ideal gas and how it’s different from an ideal gas. An ideal gas is a hypothetical concept we use when defining laws. When we say ideal gas, that means gas occupies negligible volume, the molecules are free to move without any intermolecular forces and exert high pressure. Whereas, the actual gases do occupy substantial volume, and there are intermolecular forces.
Real gases just behave close to ideal ones at very low pressure and a high temperature. In this scenario, students may ask why we study an ideal gas law when no such gas exists. The reality is the gas law is just a base for simply understanding complex things. When dealing with real gases, chemists have developed a modified form of the ideal gas equation, the Vander Waal equation, which applies to real gases.
To make your lecture more interesting and engaging, you can add some animated videos or images to your lectures.
Gases molecules are invisible to the naked eye. However, with animated videos, you can show magnified gas molecules and how they behave inside a closed container.
This image, from Labster’s simulation of Ideal Gas Law, is quite helpful for students. The experimental setup in the simulation is designed such that volume, pressure, and temperature of the gas can be changed. And you can observe how the other quantities behave when one is changed.
Discover Labster's Ideal Gas Law virtual lab today!
When studying a topic, students are generally interested in knowing where the concept is being used in the real world. Students ask themselves, why I am studying this, is it applicable anywhere? If you don’t quote a real-world example, they may misunderstand that the law has no practical applications. So, mentioning some good examples is quite important.
For instance, you can give them an example of a balloon filled with gas. When you squeeze that balloon, you are compressing it and decreasing its volume. As a result, the pressure inside increases, and then it bursts.
Moreover, if you place an air-filled balloon in hot water, you will notice a change in its size. That is because, as the temperature increases, the gas expands i.e. its volume increases. When you place the same balloon in the freezer, you will notice that its size has decreased, that’s because you lowered the temperature.
Ideal Gas law has a lot more practical applications. It is being used to determine the densities of gases and in stoichiometric calculations. The coolants/refrigerants in your refrigerator, hot air balloons in the sky, and combustion engines in vehicles, all are based on the ideal gas law. Whenever you see gases in action, keep in mind that all is possible due to the discovery of gas laws.
Experiments can also help students learn about chemical and physical laws. One way is to experiment in high-end chemistry labs. That requires a high-end infrastructure, which may not be feasible in most cases.
That’s where Labster Virtual Lab Simulations can help. At Labster, we design and create simulations that are quite different from others. Students explore the topic through a story that is set up in a 3D world. The interactive games within the stories help them learn and do fun at the same time.
In this case, you can check out our Ideal Gas law simulation. In this virtual simulation, students observe the behavior of an ideal gas molecule by altering the gas variables i.e. temperature, pressure, volume, and temperature.
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