Gujarat Board Class 9 Science — Flashcards for Quick Revision

A: Matter is anything that occupies space and has mass. Examples include air we breathe, food we eat, stones, clouds, stars, plants, animals, water droplets, and sand particles. Everything in the univers

A: Matter has two fundamental properties: 1) Mass - the amount of substance in an object (SI unit: kilogram), and 2) Volume - the amount of space occupied by matter (SI unit: cubic metre, common unit: li

A: The Panch Tatva consists of five basic elements: Air, Earth, Fire, Sky, and Water. Ancient Indian philosophers believed that everything, living or non-living, was made up of these five elements.

A: A pure substance consists of a single type of particle where all constituent particles are the same in their chemical nature. For example, pure water (H₂O) contains only water molecules.

A: A mixture contains more than one pure substance. The components can be separated by physical methods. Examples: Sea water (mixture of salt and water), Air (mixture of gases like oxygen and nitrogen).

A: Homogeneous mixtures: Uniform composition throughout, cannot see individual components. Examples: Sugar solution, salt water. Heterogeneous mixtures: Non-uniform composition, can see individual compon

A: The Law of Conservation of Mass states that mass can neither be created nor destroyed in a chemical reaction. This means the total mass of reactants equals the total mass of products in any chemical r

A: The Law of Definite Proportions states that in a pure chemical compound, elements are always present in definite proportions by mass. For example, in water (H₂O), hydrogen and oxygen are always presen

A: John Dalton proposed the atomic theory in 1808. Main postulates: (1) All matter is made of tiny particles called atoms (2) Atoms are indivisible and indestructible (3) Atoms of the same element are id