Solid, liquid, or gaseous matter can exist in one of three states. Solid matter is made up of very closely packed particles. Liquid matter is made up of particles that are more loosely packed. Gaseous stuff is made up of particles that are packed so loosely that it has no definite shape or volume.
1) London Forces or Dispersion Forces
2) Dipole – Forces of Dipole
3) Dipole Forces Induced by Dipoles
At constant temperature, the volume of a given mass of gas is inversely proportional to its pressure.
Vp = K or V 1 / p
K is a constant whose value is determined by the gas's mass, temperature, and nature.
At constant pressure, the volume of a given amount of gas grows or decreases by 1 / 273 of its volume for each degree of temperature rise or fall.
Vt = Vo (1 + t / 273) t constant p
At constant pressure, the volume of a given mass of a gas is exactly proportional to the absolute temperature.
V ∝ T (at constant p), V / T = constant or V1 / T1 = V2 / T2
Absolute zero is the lowest temperature at which the volume of a gas may potentially reach zero. It's the same as 273.15K or O°C.
Gay Lussac’s Law
For each degree of temperature rise or fall, the pressure of a given amount of gas increases or falls by 1 /273 of its pressure at constant volume.
pt = po (1 + t / 273) at constant V and n
The absolute temperature is exactly proportional to the pressure of a given mass of a gas at constant volume.
p ∝ T or p = KT or p / T = K at constant V and n or P1 / T1 = P2 / T2
It says that under the same temperature and pressure, identical volumes of all gases contain the same number of molecules.
V infi; n (at constant T and p)
Alternatively, V / n = K
Equation for a Perfect Gas
(Boyle's law) V1 / p, T, and n constants
(Charles' law) V T, p, and n constants
The constants V n, p, and T (Avogadro's law)
⇒ V ∝ nT / p
or pV ∝ nT
Alternatively, pV = nRT.
This is referred to as the ideal gas equation. The universal gas constant is R.
Density is derived from the ideal gas equation.
(where M = molecular mass) d = pM / RT
The Kinetic Theory of Gases is a theory that describes how gases move.
The following are the theory's main assumptions:
A gas is made up of many tiny particles known as molecules.
When compared to the overall volume of the gas, the amount occupied by gas molecules is minimal.
Gas molecules are in a constant state of fast random motion. The molecules clash with one another and with the container's walls.
Because the molecules are ideal elastic bodies, no kinetic energy is lost during collisions.
The gaseous molecules have no attraction forces between them.
A gas's pressure is caused by the bombardment of gas molecules against the container's walls.
Different molecules have different velocities, which means they have different energies. The average KE is proportional to absolute temperature in a direct relationship.
Abuse of the Ideal Behaviour
The gases depart significantly from their ideal behaviour under high pressure and low temperature. The compressibility factor (Z) can be used to express the deviation.
pV / nRT = Z
pV = nRT, Z = 1 in the case of an ideal gas
pV nRT, Z 1 in the case of actual gas
Deviation in the negative direction In this scenario. When the value of Z is greater than one, the gas is more compressible.
Deviation in the positive direction In this scenario. Gases with a Z greater than one are less compressible.
The elements that influence the deviation are as follows:
(i) The gas's nature The most easily liquefiable and highly soluble gases, in general, have a bigger deviation.
(ii) Tension At high pressure, the divergence is greater. At low pressure, CO2 and N2 show a negative deviation, but at high pressure, they show a positive deviation.
(iii) At low temperatures, the deviation is greater, and H2 and He always have positive deviations at O°C.
Gas Liquefaction and Critical Points
(i) increasing the amount of pressure
(ii) lowering the temperature
State of Liquid
(i) The pressure of vapour The vapour pressure of a liquid is the pressure exerted by vapours above the liquid surface when they are in equilibrium with the liquid at a certain temperature.
A liquid's vapour pressure is determined by:
(i) Liquid's nature
(ii) Temperature: As the temperature rises, so does the vapour pressure.
(ii) Boiling point refers to the temperature at which a liquid's vapour pressure equals atmospheric pressure.
Boiling point at 1 atm pressure is referred to as normal boiling point.
Boiling point at 1 bar is referred to as normal boiling point. The boiling point changes in a linear relationship with the external pressure.
(iii) Surface Tension: It's the force per unit length operating perpendicular to the imaginary line drawn on the liquid's surface. (gamma) is the symbol for it.
Nm-1 is a SI unit.
The attractive interactions between molecules determine the amount of a liquid's surface tension. It is determined using a device known as a stalagmometer.
As the temperature rises, the surface tension drops.
Surface tension causes the liquid to rise or fall in a capillary tube.
(iv) Viscosity is a term used to describe the viscosity of a Viscosity is a measurement of flow resistance caused by friction between fluid layers.