Revision: States of Matter JEE Main States of Matter

Anything that has mass and occupies space is called matter.

The process by which matter changes from one state to another and back to the original state, without any change in its chemical composition.

Polarizability is defined as the ability of an atom or a molecule to form momentary dipoles, which means, the ability of the atom or molecule to become polar by redistributing its electrons.

The electrostatic force of attraction between a positively polarised hydrogen atom of one molecule and a highly electronegative atom (which may be negatively charged) of another molecule is called a hydrogen bond.

Dipole moment (μ) is the product of the magnitude of the charge (Q) and the distance between the centres of positive and negative charge (r). It is designated by a Greek Letter (μ) and its unit is Debye (D).

The pressure exerted by saturated water vapour is called aqueous tension.

The pressure exerted by saturated water vapour is called aqueous tension.

The electrostatic force of attraction between a positively polarised hydrogen atom of one molecule and a highly electronegative atom (which may be negatively charged) of another molecule is called a hydrogen bond.

Dipole moment (μ) is the product of the magnitude of the charge (Q) and the distance between the centres of positive and negative charge (r). It is designated by a Greek Letter (μ) and its unit is Debye (D).

Polarizability is defined as the ability of an atom or a molecule to form momentary dipoles, which means, the ability of the atom or molecule to become polar by redistributing its electrons.

A temperature scale with absolute zero (zero kelvin) as the starting point is called the absolute scale or the kelvin scale.

The volume of a given mass of a dry gas varies inversely as the pressure and directly as the absolute temperature.

V ∝ \[\frac {1}{P}\] × T or \[\frac {PV}{T}\] = k (constant)

If volume changes from V₁​ to V_2​, pressure from P_1​ to P₂​, and temperature from T₁ to T₂​, then:

\[\frac {P_1V_1}{T_1}\] = \[\frac {P_2V_2}{T_2}\] = k (constant)

An atom is the smallest particle of an element that can take part in a chemical reaction; however, it may or may not exist independently. 

Avogadro s law states that "equal volumes of all gases under similar conditions of temperature and pressure contain the same number of molecules."

A molecule is the smallest particle of an element or a compound that can exist by itself; it never breaks up except for taking part in a chemical reaction.

“The relation between three properties of a gas, i.e., pressure, volume and temperature, is called the ideal gas equation.”

The process by which matter changes from one state to another and back to the original state, without any change in its chemical composition.

Anything that has mass and occupies space is called matter.

The solids which do not possess the repeating ordered arrangement of atoms or ions are called amorphous solids.

The ability of crystalline solids to change values of physical properties when measured in different directions is called anisotropy.

A basic repeating structural unit of a crystalline solid is called a unit cell.

Ferromagnetism is defined as the phenomenon in which substances, such as iron, cobalt and nickel, are strongly attracted by a magnetic field. Such substances are called ferromagnetic substances.

\[\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}\]

It states that volume of a given mass of a dry gas is directly proportional to its absolute (kelvin) temperature, if the pressure is kept constant.

OR

The pressure remaining constant, the volume of a given mass of a dry gas increases or decreases by 1/273 of its volume for each 1°C increase or decrease in temperature respectively.

\[\frac {V_1}{T_1}\] = \[\frac {V_2}{T_2}\] = k at constant pressure

It states that the volume of a given mass of dry gas is inversely proportional to its pressure at a constant temperature.
P₁V₁ = P₂V₂ = k at constant temperature

Statement:

The volume of a fixed mass of gas is directly proportional to its absolute temperature if the pressure is kept constant.

Mathematically, V ∝ T ⇒ \[\frac {V}{T}\] = constant

Graph: V vs T (Isobar)

A straight line through the origin when using Kelvin. All lines converge at 0 K (absolute zero).

Statement:

The pressure of a fixed mass of gas is directly proportional to its absolute temperature if volume is kept constant.

Mathematically, P ∝ T ⇒ \[\frac {P}{T}\] = constant

This means: heating a gas in a sealed (rigid) container increases its pressure.

Graph: P vs T (Isochore)

P vs T graph at constant volume — a straight line through the origin (Kelvin scale).

Statement:

For a fixed mass of gas at constant temperature, the pressure is inversely proportional to the volume.

Mathematically, P ∝ \[\frac {1}{V}\] ⇒ PV = constant

Graph: P vs V (Isotherm)

This means: squeezing a gas into a smaller space increases its pressure. Doubling the pressure halves the volume.

Faraday’s first law of electrolysis: The mass of a substance deposited or liberated at an electrode is directly proportional to the quantity of electricity passed through the electrolyte.

Given: Charge passed = 9650 C

Atomic mass of Cu = 63.5

Valency of Cu in CuSO₄ = 2

Equivalent mass of Cu = `63.5/2` = 31.75

Now, Mass deposited = `9650/96500 xx 31.75`

= 0.1 × 31.75

= 3.175 g

Faraday’s first law of electrolysis: The mass of a substance deposited or liberated at an electrode is directly proportional to the quantity of electricity passed through the electrolyte.

Given: Charge passed = 9650 C

Atomic mass of Cu = 63.5

Valency of Cu in CuSO₄ = 2

Equivalent mass of Cu = `63.5/2` = 31.75

Now, Mass deposited = `9650/96500 xx 31.75`

= 0.1 × 31.75

= 3.175 g