Karnataka Board Class 9 Science — Flashcards for Quick Revision

A: Hot food particles have more kinetic energy and move faster. They diffuse quickly into air particles and reach our nose in less time. Cold food particles move slowly, so diffusion is slower and smell

A: Water particles have weak forces of attraction and more space between them, allowing easy movement. Wood particles have strong forces of attraction and are closely packed, making it rigid and difficul

A: During evaporation, surface particles absorb energy from surroundings to escape as vapor. This removes heat energy, causing cooling. Example: Sprinkling water on roof during summer cools it as water e

A: Yes! Total mass of reactants = 5.3 + 6 = 11.3 g. Total mass of products = 2.2 + 0.9 + 8.2 = 11.3 g. Since mass before = mass after, this confirms the law of conservation of mass - matter cannot be cre

A: Using the law of constant proportions, hydrogen and oxygen combine in a fixed 1:8 ratio. For 6 g hydrogen: 6 × 8 = 48 g of oxygen needed. This demonstrates that elements always combine in definite pro

A: Atoms are incredibly small (radius ~10⁻¹⁰ m). Millions of atoms stacked together would barely equal the thickness of paper. They're smaller than the wavelength of visible light, so our eyes cannot det

A: Scientifically, pure means all constituent particles are the same in chemical nature. A pure substance consists of a single type of particle. Commercial 'pure' salt may still contain impurities, but c

A: Copper sulphate forms a homogeneous mixture (solution) where particles are evenly distributed at molecular level, creating uniform appearance. Oil and water form a heterogeneous mixture due to differe

A: Mass of solute = 25g, Mass of solvent = 100g, Mass of solution = 25 + 100 = 125g. Mass percentage = (Mass of solute/Mass of solution) × 100 = (25/125) × 100 = 20%. The solution is 20% sugar by mass.