Intermolecular forces in liquids are stronger than in gases. Liquid have definite (fix) volume and they can flow and take the shape of the container in which these liquids are stored. These online education classes degree notes are published by ChemistryNotesInfo.com and hosted at ChemistryNotesInfo.blogspot.com Vapour pressure, viscosity, surface tension are some physical properties of liquids which are described below-
Pressure exerted by the vapors on the walls of the container containing liquid is known as vapour pressure.
· Vaporization depends on temperature
· Vapour pressure at which equilibrium is achieved between liquid phase and vapor phase is known as Saturated Vapour Pressure or Equilibrium Vapour Pressure
· Boiling is a condition of free vaporization means vapor extends freely into the surroundings.
· Boiling temp. at 1 atm pressure is known as Normal Boiling Point
· Boiling temp. at 1 bar pressure is known as Standard Boiling Point
· Temp. at which clear boundary between liquid and vapors disappear is known as Critical Temperature
Liquids tends to minimize their surface area because molecules of the liquid on the surface experience net attractive force towards the interior of the liquid, this characteristic property of the liquid is known as Surface Tension.
Example: Mercury do not form thin film and capillary action
It is a measure of resistance to flow that arise due to internal friction between the layers of liquid (or fluid), when they slip over one another, during the flow of liquid or fluid.
· Force required to maintain flow of liquid layers is-
Where, A is area of contact,
du/dz is velocity gradient,
is coefficient of viscosity.
SI unit of is “Newton second per square meter (Nsm-2)”
cgs unit of is “poise”
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