CBSE Class 11-science Chemistry States of Matter
Intermolecular Forces
Attractive intermolecular forces are called Van der Waals forces.
Dipole-dipole forces exist between polar molecules, dipole-induced dipole forces exist between polar and non-polar molecules and London Forces also called dispersion forces exist between non polar molecules.
Hydrogen bonding is special type of Dipole-dipole force.Effect of Heat on Matter
The three states of matter are the result of balance between intermolecular forces and thermal energy.
Higher melting and boiling point of substances are due to size i.e. higher molecular weight and intermolecular forces.
Properties like sublimation and compressibility are affected by intermolecular forces.Gas Laws
Pressure-Volume relation is known as Boyle's law. Volume-temperature relation as Charles's law. Pressure-temperature relation is known as Gay Lussac's law.
Amount of gas-volume relation is known as Avogadro's law.
Dalton's law of partial pressure states that the total pressure of a mixture of non-reactive gases is the sum of individual pressures exerted by each gas.Ideal Gas Equation.
According to postulates for an ideal gas, it consists of minute particles, continuously colliding with no loss of energy during collision, negligible intermolecular forces and average kinetic energy being proportional to absolute temperature.Kinetic Theory
The deviation from ideal behaviour is large at high pressure and low temperature because the intermolecular forces start operating between the molecules.
Under suitable conditions of temperature and pressure conditions gases can be liquefied.
The critical temperature is the temperature above which distinct liquid and gas phases do not exist.Properties of Liquid
For a liquid-vapour equilibrium, the pressure of vapour in equilibrium with its liquid phase is known as Equilibrium Vapour Pressure.
Surface tension is defined as the force acting at right angles per unit length.
Viscosity is the measure of resistance to flow. Increase in temperature decreases surface tension and viscosity.
