Kinetic Theory of Matter and States of Matter

These flashcards cover the vocabulary and key scientific concepts from the lecture on matter, its states, and the kinetic theory of matter, including phase changes and molecular characteristics.

Matter

Anything that has mass and occupies space, such as a table, cloth, or air.

Akash, Vayu, Tejas, Jal, and Prithvi

The five elements Indian philosophers believed all matter was made of, representing Sky, Air, Fire, Water, and Earth.

Parmanu

Indivisible particles that Maharishi Kanad, in the 6th century, claimed made up matter.

Molecule

The smallest unit that has all the properties of a substance, which is made up of even smaller units called atoms.

Monoatomic molecules

Molecules that contain only one atom, such as Neon ($Ne$) and Argon ($Ar$).

Diatomic molecules

Molecules that contain two atoms, such as hydrogen ($H$) and oxygen ($O$).

Triatomic molecules

Molecules containing three atoms, such as water ($H_2O$), which has two hydrogen and one oxygen atom.

Polyatomic molecules

Molecules containing four or more atoms, such as sulphuric acid ($H_2SO_4$).

Intermolecular space

The space between molecules, which is minimum in solids and maximum in gases.

Intermolecular force of attraction

The force that molecules use to attract one another, working only within a short distance of about $10\,nm$.

Force of cohesion

The attraction between molecules of the same substance, such as water droplets sticking together.

Force of adhesion

The attraction between molecules of different substances, such as water droplets sticking to a glass surface.

Surface tension

The property of a liquid by which its surface acts like a stretched elastic sheet.

Viscosity

The property of a liquid that resists its flow.

Kinetic Theory of Matter

The theory stating all matter is made of tiny particles in constant motion, where movement depends on kinetic energy (energy of motion).

Aerogel

The world's lightest solid, created by removing liquid from a gel, leaving a structure that is $99\%$ air.

Change of state

The process where a substance transforms from one state (solid, liquid, or gas) to another due to the absorption or release of heat at a constant temperature.

Melting

The process of a solid changing into a liquid upon heating.

Melting point

The fixed temperature at which a solid turns into a liquid; for example, the melting point of ice is $0^{\circ}C$.

Fusion

The process in which a solid absorbs heat and changes into a liquid without a rise in temperature, using the heat to break bonds between particles.

Freezing

The process where a liquid changes into a solid on cooling as particles lose energy and form a fixed structure.

Boiling (Vaporisation)

The process in which a liquid changes into vapour throughout its volume when heated to a fixed temperature.

Boiling point

The fixed temperature at which a liquid turns into steam or vapour; for water, this is $100^{\circ}C$.

Condensation

The change of a gas into a liquid upon cooling, occurring at a fixed temperature called the condensation point.

Sublimation

The process where certain solids, like camphor or naphthalene balls, change directly into gas without becoming a liquid.

Deposition

The reverse of sublimation, where a gas changes directly into a solid without becoming a liquid.

Evaporation

A surface phenomenon where a liquid changes into gas at temperatures below its boiling point.

Humidity

The amount of water vapour present in the air, which can slow down the rate of evaporation if levels are high.