Scientists use the Ideal Gas Law to help understand how gases behave, even though real gases often act differently. The Ideal Gas Law is shown with this equation:

PV = nRT

Here’s what the letters mean:

• P = pressure of the gas (measured in atmospheres or pascals)
• V = volume of the gas (measured in liters or cubic meters)
• n = amount of gas (measured in moles)
• R = ideal gas constant (0.0821 L·atm·K⁻¹·mol⁻¹)
• T = temperature of the gas (measured in Kelvin)

Differences Between Ideal and Real Gases

Ideal Gases:

• The Ideal Gas Law assumes gas particles don't interact with each other. That means there are no forces pulling them together or pushing them apart.
• It also assumes that the size of the gas particles is very small compared to the size of the container they are in.
• This law works best when temperatures are high and pressures are low.

Real Gases:

• Real gases do have forces between their particles, especially when they are at high pressures and low temperatures.
• Real gases take up space because their particles have size.
• When pressure is really high (over 1 atm) or the temperature is really low (under 273 K), real gases start to act differently from what the Ideal Gas Law predicts.

Why We Use Ideal Gas Laws

1. Easy to Use:

   • The Ideal Gas Law gives a simple way to predict how gases will behave.
   • It makes math easier and helps in labs where conditions might not match what happens with real gases.

2. Works for Many Gases:

   • Many gases act like ideal gases in different situations. For example, noble gases like helium and neon behave closely to the ideal model because their particles barely attract or repel each other.
   • Studies show that noble gases can be treated as ideal with about 90% accuracy when at standard temperature and pressure (STP). This means 0°C (273 K) and 1 atm.

3. Useful for Science:

   • The Ideal Gas Law helps in creating other important science rules and is widely used to study energy, efficiency, and how different gases behave.

4. Simple Calculations:

   • Scientists can use the Ideal Gas Law for simple experiments without needing complicated math that considers real gas behavior, like the Van der Waals equation that looks at particle size and the forces between them.

Limitations of Ideal Gas Laws

Even though the Ideal Gas Law is helpful, it has some limits:

• High Pressures: At pressures higher than 5 atm, real gases can behave very differently, like carbon dioxide, which can turn into a liquid under high pressure (like 50 atm at 20°C).

• Low Temperatures: At temperatures below -100°C, gases like ammonia can show big differences from ideal behavior because they form strong bonds with other molecules.

In real-life science, while the Ideal Gas Law is a good starting point, understanding how real gases act in different conditions is important for making accurate predictions and running experiments in chemistry.