Punjab Board Class 9 Science — Flashcards for Quick Revision

A: Matter is anything that has mass and occupies space (has volume). Examples: The chair you sit on, the air you breathe, water you drink, the book you read, your pencil, etc. Everything in our surroundi

A: The salt did not disappear; it broke down into tiny particles that spread throughout the water. This shows that matter is made up of small particles. The salt particles got into the spaces between wat

A: This demonstrates that particles of matter are incredibly small. Just a few visible crystals contain millions of tiny particles. When diluted repeatedly, the color still spreads because each particle

A: A pure substance is matter that consists of a single type of particle where all constituent particles are identical in their chemical nature. All particles have the same chemical composition throughou

A: Milk appears uniform but is actually a mixture because it contains multiple substances (water, fat, proteins, lactose, minerals) that are not chemically bonded in fixed proportions. While it looks lik

A: This solution is HOMOGENEOUS because copper sulphate completely dissolves in water, forming a uniform mixture at the molecular level. The copper sulphate particles (solute) are evenly distributed thro

A: The Law of Conservation of Mass states that mass can neither be created nor destroyed in a chemical reaction. In other words, the total mass of reactants (starting substances) always equals the total

A: To verify the Law of Conservation of Mass, we compare total mass of reactants with total mass of products: Reactants: sodium carbonate (5.3 g) + acetic acid (6 g) = 11.3 g Products: carbon dioxide (

A: The Law of Constant Proportions states that in a chemical compound, the elements are always present in definite proportions by mass, regardless of the source or method of preparation. For example, in