State of Matter Class 11 Notes PDF

Detailed Table of the Chapter 5 Notes – State of Matter Class 11 Notes PDF

State of Matter Class 11 Notes PDF – Short Notes

The substance that contains mass and occupies space is known as Matter. Atoms and molecules constitute matter. It has various physical and chemical properties. Matters are classified into solid, liquid, and gas. The force of interaction present in them varies which gives rise to its physical properties. Gases have the least force of interaction, while solids have the highest force of interaction.

1. Intermolecular Forces

The molecules like solid, liquid, or gas exhibit forces of attraction which are called intermolecular forces. Van der Waal forces are the collective of dipole-dipole, dipole-induced dipole, and dispersion forces. Ion-dipole and ion-induced dipole are not Van der Waal forces. Hydrogen bonding is the strongest force of attraction.
The Different Types of Intermolecular Forces are:
1.1 Dipole-Dipole Interaction
Polar molecules exhibit dipole-dipole interactions. They have permanent dipole moments. The positive pole and negative pole are attracted to the molecule. For example,
HCl.HCl.
In
HClHCl
the molecule, ClCl is more electronegative than hydrogen. So, the chlorine atom acquires a negative charge while the hydrogen atom acquires a positive charge. Thus, dipole-dipole interaction takes place among them.
1.2 Ion-Dipole Interaction
The attraction between the cation, anion, and a polar molecule is known as ion-dipole interaction. For example,
NaCl.NaCl.
The polar water molecules are attracted towards Na+Na+ and Cl−Cl− on dissolving
NaClNaCl
in water.
1.3 Ion-induced Dipole Interaction
The interaction between the non-polar molecules when a polarized ion is brought near to it is known as ion-induced dipole interaction. For example, an iodine molecule that is not polar gets polarized in the presence of a nitrate ion.
1.4 Dipole Induced Dipole Interaction
The interaction between the non-polar molecules when a polarized dipole is brought near to it is known as dipole-induced dipole interaction. For example, in the presence of polar molecules, noble gases get polarized.
1.5 London forces or Dispersion forces
For instance, the electron cloud of the molecule gets distorted for the generation of an instantaneous dipole. The momentary dipole is produced in the molecule in which one part of the molecule is more negative than the other part. The momentary dipole produced induces a dipole in the other molecule. Thus, the force of attraction between the induced momentarily dipole is known as London dispersion forces.

2. Intermolecular Forces Versus Thermal Energy

The force of interaction tries to bring the molecules closer. That is, the solid possesses the strongest intermolecular force of attraction, while the gases possess the least intermolecular force of attraction. The decreasing order is,
Solid>Liquid>GasSolid>Liquid>Gas
The thermal energy is possessed by the molecule. The kinetic energy helps in the movement of particles. The gas possesses the highest thermal energy, while the solid possesses the least thermal energy. The decreasing order is,
Gas>Liquid>SolidGas>Liquid>Solid

State of Matter Class 11 Notes PDF – Important Points

3 Ideal Gas
An ideal gas is a hypothetical concept. There are various assumptions of an ideal gas. Some of them are:
The force of interaction between the molecules is zero.
The volume of the molecules is very small. The molecules of the gas collide with each other and with the walls of the container.

4. State of a Gas and State Variable

The physical condition of the system is the state of a gas. The variables which are used to denote the physical condition of a gas are known as state variables. They are pressure, volume, and temperature (P,V and T).(P,V and T).
4.1 Pressure
The force exerted on an object per unit area is known as pressure. The force applied is always perpendicular to the object. The unit of pressure is the pascal. Pressure can be measured by various instruments. Barometer and manometer are used to measure pressure.
4.2 Volume
The volume of the gas is the same as the volume of the container in the case of rigid containers. For non-rigid containers, the volume of the gas is determined by the number of moles and other state functions.
4.3 Temperature
The amount of heat contained in the gas can be measured by the physical term temperature. No heat flows in and out of the gas when the temperature of the gas is equal to the surrounding temperature. The thermometer is used to measure the temperature of the gas. The units of temperature are Celsius, kelvin, and Fahrenheit.

5. Ideal Gas Law

The laws relate the state variable of the gas in two states.
5.1 Boyle’s Law
It gives the relation between pressure-volume. At a constant temperature, the pressure of a fixed amount of gas is inversely proportional to its volume. The value of the proportionality constant for each curve corresponds to a different constant temperature and is known as isotherm. Mathematically, it can be written as,
PPPV∝==1VkVkP∝1VP=kVPV=k
As PVPV increases, the corresponding temperature will also increase.
5.2 Charles’s Law
It gives the relation between temperature-volume. At constant pressure, the volume of a fixed mass of gas is directly proportional to the absolute temperature. Mathematically, it can be written as,
VVk∝==TkTVTV∝TV=kTk=VT
5.3 Gay-Lussac’s Law
It gives the pressure-temperature relationship. At fixed volume, the pressure of a fixed mass of gas is directly proportional to the absolute temperature. Mathematically, it can be written as,
PPk∝==TkTPTP∝TP=kTk=PT
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