Give reasons: hot sizzling food reaches several metres away, but for cold food you have to go close.

The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close.

The smell of hot sizzling food travels several meters due to the high kinetic energy and rate of diffusion of its volatile particles (शीघ्र वाष्‍प रूप हो जाने वाला). Activated by heat, these particles move quickly and spread the smell widely. In opposite, cold food emits less volatile particles with less kinetic energy, requiring the individual to perceive the smell more closely.

“Need the answer for Related: NCERT Solutions Chapter 1 Matter in Our Surroundings”

• Which of the following are matter? Chair, air, love, smell, hate, almonds, thought, cold, lemon water, smell of perfume.
  Matter is anything that has mass and takes up space. Based on this definition, the items that are matter in the given list are: Chair, air, almonds, cold, lemon water, and smell of perfume. The rest (love, smell, hate, thought) are abstract concepts and do not have mass or occupy space in the same way that physical objects do.
• Give reasons: hot sizzling food reaches several metres away, but for cold food you have to go close.
  The smell of hot sizzling food travels several meters due to the high kinetic energy and rate of diffusion of its volatile particles (शीघ्र वाष्‍प रूप हो जाने वाला).
• A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?
  Fluidity refers to the ability of a substance to flow and change shape when subjected to an external force. Liquids, such as water in this case, exhibit fluidity because their particles can move past each other relatively easily while still maintaining some cohesive forces.
• What are the characteristics of the particles of matter?
  Mass and Volume,, Continuous motion, State variability, Energy levels
• The mass per unit volume of a substance is called density. (density = mass/volume).Arrange the following in order of increasing density – air, exhaust from chimneys, honey, water, chalk, cotton and iron.
  The order from lowest to highest density would be: Air, Exhaust from chimneys, Cotton, Water, Honey, Chalk, Iron.
• Tabulate the differences in the characterisitcs of states of matter.
  Solid: Definite shape, volume, dense.Liquid: Takes shape of container, definite volume, less dense than solids.Gas: Fills container, no definite shape/volume, least dense.
• Comment upon the following:
  Rigidity, compressibility, fluidity, and more! This description explores key properties of matter (shape, density, kinetic energy) with definitions, comparisons, and examples. Learn how solids, liquids, and gases behave!
• Give reasons: Gas fills completely the vessel
  A gas fills completely the vessel in which it is kept: Gas particles have high kinetic energy and move randomly, spreading out to fill all available space.

“Need the answer for Related: NCERT Solutions Chapter 2 Is Matter Around Us Pure”

• What is meant by a substance?
  Substances can exist in various forms, including solids, liquids, and gases. Examples of substances include water (H2O), salt (NaCl), oxygen (O2), and iron (Fe).
• List the points of differences between homogeneous and heterogeneous mixtures with examples
  These points highlight the fundamental differences between homogeneous and heterogeneous mixtures in terms of their composition, appearance, and behavior.
• How are sol, solution and suspension different from each other?
  Sols as having small floating particles, solutions as clear mixtures with tiny particles dissolved, and suspensions as having visible particles that may settle down over time.
• To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water
  Concentration of the saturated solution of sodium chloride at 293 K is approximately 0.358 g/mL.
• Classify each of the following as a homogeneous or heterogeneous mixture. soda water, wood, air, soil, vinegar, filtered tea.
  A solution is a homogeneous mixture, meaning its components are evenly distributed throughout and cannot be easily separated by physical means like filtration.
• Name the technique to separate (i) butter from curd, (ii) salt from sea-water, (iii) camphor from salt.
  Butter from curd, we can use the technique of churning (Centrifugation), salt from seawater, process of evaporation, camphor from salt, we can use the technique of sublimation.
• What type of mixtures are separated by the technique of crystallisation?
  Crystallisation is used to separate homogeneous mixtures, specifically solutions where the solute can form crystals.
• Classify the following as chemical or physical changes:
  Cutting of trees: Physical Change, Melting of butter in a pan: Physical Change, Rusting of almirah: Chemical Change, Boiling of water to form steam: Physical Change, etc.