Gujarat Board Class 10 Science — Flashcards

A: The four key observations are: 1. Change in state (solid to gas, liquid to solid, etc.) 2. Change in colour 3. Evolution of a gas 4. Change in temperature Example: When magnesium ribbon burns, it cha

A: A chemical equation is a symbolic representation of a chemical reaction showing reactants and products using chemical formulae. - Reactants: Substances that undergo chemical change (written on the le

A: A skeletal chemical equation is the unbalanced form showing only the types and numbers of atoms of each element as they appear in reactants and products. It must be balanced because of the Law of Con

A: An acid-base indicator is a dye or mixture of dyes used to indicate the presence of acids and bases through color changes. Examples: (1) Litmus - blue litmus turns red in acidic solution, red litmus t

A: Acids produce H+ ions only in aqueous (water) solution. In the absence of water, acid molecules do not ionize. For example, dry HCl gas does not change the color of dry litmus paper, but HCl solution

A: Chemical equation: Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g). The gas evolved is hydrogen gas (H2). This is a characteristic reaction of metals with acids - the metal displaces hydrogen from the acid, for

A: This is likely an ionic compound or a pure metal like copper or sodium. In solid state, ions are fixed in rigid lattice structure and cannot move. When molten, the heat energy overcomes electrostatic

A: Sodium is highly reactive with both oxygen and water. It reacts vigorously with oxygen in air to form sodium oxide (Na₂O), and explosively with water: 2Na + 2H₂O → 2NaOH + H₂ (gas that catches fire).

A: Malleability: Ability of metals to be beaten into thin sheets (e.g., aluminum foil, gold leaves for decoration). Ductility: Ability to be drawn into thin wires (e.g., copper wires for electrical circu