(L19) Thermodynamics 3 Flashcards
What is an ideal gas?
A theoretical gas, randomly moving point particles that are not subject to interparticle interaction.
- particles have no volume
- collisions are elastic (no energy lost)
- no interaction between particles
What is a real gas?
A real gas:
Subject to
- inelastic collisions
- particles have volume
- intermolecular forces
What is a theoretical gas equation?
PV = nRT.
Real gases behave like ideal gases:
- at high temp,
- at low pressure
What is a phase change?
ideal gas relationship PV=nRT fails!
Attractive forces between the atoms of gas forces the atoms to stick together. The gas condenses to a solid or liquid.
What is vapor?
Vapor is a substance in gas phase at a temperature lower than its critical temperature.
Which means the vapor can be condensed too a liquid, increasing pressure on it without reducing the temp of vapor.
What is critical temperature?
Temp that when passed, vapor can not be returned to a liquid no matter how much pressure is applied.
What is Sublimation ?
directly from solid –> gas
What is Deposition ?
directly from gas –> solid (reverse of Deposition)
What is Melting ?
from solid –> liquid
What is Fusion ?
from liquid –> solid (reverse of melting)
What is vaporisation or evaporation?
from liquid –> gaseous
What is Condensation ?
from gas –> liquid
What is triple point?
Occurs when both pressure and temperature of the 3 phases of the substance coexist in equilbrium
What is a isotherm?
Point on a map that connects 2 regions of temperature
(joining points representing states of equal temperature)
pressure of isotherms are constant
it is independent of volume
