0
Upcoming SlideShare
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Standard text messaging rates apply

# Tp 10 energy of an ideal gas (shared)

247

Published on

Published in: Education
0 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

• Be the first to like this

Views
Total Views
247
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
8
0
Likes
0
Embeds 0
No embeds

No notes for slide

### Transcript

• 1. A-level Physics Unit G484: The Newtonian World Mean energy of particles in an ideal gasThermal physics
• 2. Temperature LOs Temperature can be defined as a measure of the ‘hotness’ of a body. To do • When we measure the temperature of a gas what is it telling us? • Recall the assumptions behind an ideal gas: which of them deal with the energy of its particles? • Imagine cylinders of hydrogen and oxygen at the same temperature. What differences – if any – would you notice between the molecules of gas in each cylinder?Thermal physics
• 3. Ideal gases: simplifying assumptions LOs An ideal gas is one that obeys Boyle’s law at all temperatures. On a microscopic scale, an ideal gas: • consists of a large number of particles (atoms or molecules) in constant motion at high speed; • collisions between particles and between particles and the walls of a container are perfectly elastic (kinetic energy is conserved); • there are no intermolecular forces except during instantaneous collisions; • the total volume of particles is very small compared with the volume of the container. A gas fitting this description is called an ‘ideal gas’. Normal gases (especially dilute gases) come close to meeting the description.Thermal physics
• 4. Lesson focus • Mean energy of particles in an ideal gasThermal physics
• 5. Learning outcomes All of you should be able to • describe the energy of an ideal gas; • explain what temperature tells us about a gas; • recall the link between the kinetic energy of an ideal gas and its temperature; • solve simple problems concerning the energy of an ideal gas. Most of you should be able to • solve more complex problems concerning the energy of an ideal gas.Thermal physics
• 6. The meaning of temperature LOs The pressure of an ideal gas is given by the following equation: p = ⅓ ρ‹c2› where, ρ - density ‹c2› - ‘mean squared speed’ of gas particles To do • Using this equation, derive an expression starting ‘ pV = … ’ [hints: ρ = ? total mass of gas, M = ? ] • Now equate your expression with one form of the ideal gas equation. LO 1: explain that the mean translational kinetic energy of an atom in anThermal physics ideal gas is directly proportional to the temperature of the gas in kelvin
• 7. The meaning of temperature LOs LO 1: explain that the mean translational kinetic energy of an atom in anThermal physics ideal gas is directly proportional to the temperature of the gas in kelvin
• 8. The meaning of temperature LOs Key result The mean kinetic energy of a gas particle is directly proportional to the absolute (kelvin) temperature of the gas. i.e. Ek T Note This equation describes the translational kinetic energy of particles in a monatomic gas. Diatomic (or other non-monatomic) gases also possess rotational and vibrational k.e.. LO 1: explain that the mean translational kinetic energy of an atom in anThermal physics ideal gas is directly proportional to the temperature of the gas in kelvin