Question 2
(a) Tabulate the differences in the characteristics of states of matter.
(b) Comment upon the following:
rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.
(a) The difference in the characteristics of the three states of matter are:
| Characteristics | Solid | Liquid | Gas |
|---|---|---|---|
| Shape | Fixed shape | No Fixed shape | No Fixed shape |
| Volume | Fixed volume | Fixed volume | No Fixed volume |
| Intermolecular force | Maximum | Less than solids | Very less |
| Intermolecular space | Very less | More than solids | Maximum |
| Compressibility | Negligible | Compressible | Highly compressible |
(b) (i) Rigidity — It is the property of matter to continue to remain in its shape when treated with an external force.
(ii) Compressibility — It is the property of the particles of matter to contract their intermolecular space when exposed to an external force, thereby increasing its density.
(iii) Fluidity — It is the ability of a substance to flow or move about freely.
(iv) Filling a gas container — The particles of gas fill the entire container as the intermolecular spaces between the gas molecules is very large and hence the particles are free to move about in all directions.
(v) Shape — It is the definite structure of an object within an external boundary
(vi) Kinetic energy — Motion allows particles to possess energy which is referred to as kinetic energy.
K.E = mv2, where
'm' is the mass and
'v' is the velocity of the particle.
(vii) Density — It is the mass of a unit volume of a substance.
d = , where
d is the density,
m is the mass and
v is the volume of the substance
Chapter 1: Matter in Our Surroundings — Quick Reference
Quick Revision Points
- Matter has mass and occupies space; made of particles with spaces, motion, and attraction
- Three states: Solid (fixed shape/volume), Liquid (fixed volume, not shape), Gas (neither fixed)
- Melting point of ice = 0°C (273 K); Boiling point of water = 100°C (373 K)
- Latent heat of fusion of ice = 334 J/g; Latent heat of vaporisation of water = 2260 J/g
- Sublimation: solid → gas directly (camphor, dry ice, naphthalene)
- Evaporation: surface phenomenon at all temperatures; causes cooling; factors: surface area, temperature, humidity, wind
- Temperature conversion: T(K) = T(°C) + 273
- Read the detailed chapter notes for complete coverage of all NCERT topics.
- Practice all NCERT in-text and back exercise questions — they are frequently asked in exams.
- Focus on comparison tables, diagrams, and definitions — these are high-scoring areas.
- For numericals (if applicable), practice at least 20 problems of varying difficulty.
- Refer to the practice question bank (200+ questions) for thorough preparation.
- Detailed Notes: ch01-matter-in-our-surroundings.html
- Practice Questions: 100+ questions with answers in 05-practice-questions/
- Chapter Test: 30-mark test paper in 06-tests/chapter-tests-30marks/
- Formula Sheet: Complete formula reference in 03-teacher-aid/formula-sheet.html