States of Matter

The Kinetic Theory of Matter

i      All matter is composed of small particles.

ii     The particles of matter are in constant motion.

iii     All collisions between the particles of matter are perfectly elastic

Particle motion: atoms move in a straight line between collisions.

The Solid State

Gases: The Kinetic Theory
Two of the basic assumptions of this theory are:

• Actual volume of gas molecules in negligible as compared to the volume occupied by the gas
• Intermolecular forces between gas molecules are negligible

What are Ideal Gases?
These are the gases which obey the kinetic theory of gases. 

Under what conditions of temperature and pressure do gases deviate from ideal behaviour?

1. Low Temperature
2. High pressure

Smaller molecules like Helium, Nitrogen and Hydrogen behave more ideally due to their smaller molecular size, hence minimal intermolecular forces of attraction. 
Othher gases like Ammonia, Hydrogen Chloride and Sulphur dioxide deviate more from the ideal behavior due to much stronger intermolecular forces.


The Ideal Gas Equation

PV=nRT

wWhere,

P=Pressure of gas in Pascals or Newton per metre squared

V=Volume of gas in m(3) (metre cubed)

n= Number of moles of gas

R= Ideal gas constant 8.31 J /K mol

T= Temperature of gas in kelvins

Calculating Mr of a gas from the ideal gas equation

Mr = mass x (R) (T)

              (P) x (V)

The Liquid State: Vaporization and Vapor pressure

Vapor Pressure

It is the pressure exerted by the vapors of a liquid when they are in a state of dynamic equilibrium
Factors affecting vapor pressure;

• Temperature
• Intermolecular forces
  

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