Deviation from Ideal Gas Law
Caleb Thomas
7 min read
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Study Guide Overview
This study guide covers the Kinetic Molecular Theory (KMT), including its assumptions and how ideal gases behave. It explains real gas deviations from ideal behavior at low temperatures and high pressures, and touches upon the Van der Waals equation. It also discusses diffusion and effusion, including Graham's Law. Finally, it provides practice questions and exam tips.
#AP Chemistry: Gases - The Night Before 🚀
Hey there, future AP Chem master! Let's make sure you're feeling confident about gases. We'll break down everything you need to know, focusing on key concepts and test-taking strategies. Let's get started!
#Kinetic Molecular Theory (KMT) and Ideal Gases
First, let's recap the five assumptions of the Kinetic Molecular Theory (KMT) which describes the behavior of ideal gases:
- No attractive or repulsive forces between gas particles.
- Gas particles have negligible volume compared to the space between them.
- Gas particles move in random, constant, straight-line motion.
- Collisions are elastic (no energy loss).
- Average kinetic energy of gas particles is directly proportional to temperature (KE = 1/2mv²). All gases have the same average KE at a given temperature.
Ideal gases follow these rules perfectly. Real gases, however, deviate, especially at low temperatures and high pressures.
# When Do Gases Deviate from Ideal Behavior? 🤨
Real gases deviate from ideal behavior under conditions of low temperatures and high pressures. Here's why:
#➡️⬅️ Attractive Forces Become Significant
- At low temperatures 🌡️, gas particles slow down and spend more time near each other, increasing attractive forces.
- Polar molecules and larger molecules have stronger intermolecular forces (IMFs), causing them to deviate more from ideal behavior.
Real gas pressure is usually lower than ideal gas pressure due to these attractive forces. Particles are pulled inward, hitting the container walls less often.
#Significant Particle Volume
- At high pressure, the volume of the container decreases, making the volume of the gas particles more significant.
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