Answers section
Questions 2.12
- Name the three (3) physical states of matter. --------------------------
- Explain why liquids and gases have no definite shape, but take the shape of the container.---------------
- Liquids have definite volume but gases do not. Explain. -------
- State the properties that are common to all the three states of matter?--
- Explain why
- solids have definite shape and volume-------------------
- liquids have definite volume but indefinite shape---------------------------
- gases have no definite volume.----------------
Answers to Questions 2.12
- Solid, liquid, and gas
- Particles (molecules) of liquids and gases move freely and randomly; so they spread till they reach the wall of the container. Accordingly, they take the shape of the container.
- The upward spread of molecules in liquids is prevented by surface tension. Gases do not have a surface; so their molecules spread freely upwards for as long as there is space. Their volume is therefore the volume of the container.
- Tiny invisible particles. Continuous movement of particles. Mass.
- Particles in solids vibrate at fixed positions; so they have no tendency to spread out and change shape or volume.
- Upward movement of molecules of a liquid is prevented by surface tension; so volume does not change. But they can spread horizontally upto the wall of the container; so they take the shape of the container.
- Molecules of a gas move freely and randomly in all directions, but with no surface tension; so they spread out in all directions, provided there is space.