In earlier blogpost, we have mentioned on the basic assumptions of kinetic theory as applied to Ideal Gas.
Today, we shall continue to discuss on what really is a Real Gas and how it differs from the Ideal Gas (and thus its assumptions).
A Real Gas has the following features:
1. Gas particles have a certain volume and size – the particles cannot just move anywhere in the container
2. Intermolecular forces of attraction exist between the gas particles, though they are usually weak – the particles tend to stick together and thus reduces the pressure of the container slightly
Now, so when can a Real Gas behaves like an Ideal Gas?
A Real Gas is most like an Ideal Gas under the following conditions:
1. At Low Pressures:
– Gas particles are widely spaced apart and thus they have negligible size (and volume)
– Intermolecular forces of attraction between gas particles are virtually zero
2. At High Temperature:
– Negligible intermolecular attractions since the gas particles have sufficient kinetic energy to overcome it
In another way of putting it, this means a
Real Gas will shows the Biggest Deviation from Ideality:
1. At High Pressures
– Gas particles are packed so close together, and the size of a gas molecule cannot be assumed to be negligible
2. At Low Temperature
– Low kinetic energy and the intermolecular forces of attractions between gas particles are significant
The above concepts will be required for A-Levels H2 Chemistry Exams, but many students do not know the key concepts itself, and how to apply them to solve questions.
This is what many of my JC students attending our H2 Chemistry Weekly Tuition Classes told us. Many of their lecturers actually classify this topic as ‘E-learning’ or ‘Self-Learning’ and ask the students to read through the notes on their own. Beware!
In the next post, i will share with you how different Real Gases deviate from Ideal Gas behaviour to a different extent.
Stay tuned to it!
PS: How do you find the Chemistry Tips so far in this blogpost? Leave me a comment, i would love to hear from you =)