Matter in our surroundings

• Matter- Anything that has mass and occupies space
• Matter is made up of very tiny pieces called particles
• Characteristics of particles of matter are

  1. They are very very small
  2. They are in continuous motion
  3. They have space between them
  4. They attract each other
• The intermixing of the particles of two different matter on their own is called diffusion
• The particles of matter have kinetic energy.

  the rate of DIFFUSION increases, when the temperature increases
• The three types of matter are- solid, liquid and gas
• Solids:

  • Particles are tightly packed together with a fixed shape and volume
  • Maximum density and rigidity
  • Not compressible
  • Maximum force of attraction between particles
• Liquids:

  • Particles are loosely packed with no fixed shape
  • Have a fixed volume
  • Density is less than solids but more than gases
  • Considered fluids and not compressible
  • Force of attraction between particles is less than solids but more than gases
• Gases:

  • Particles are very loosely packed with a lot of space between them
  • No fixed shape or volume
  • Minimum density
  • Considered fluids
  • Highly compressible
  • Minimum force of attraction between particles
• S.I Unit of temperature: Kelvin (K)

  0°C = 273 K

  Therefore, temperature in kelvin= temperature in °C + 273

  and, temperature in °C= temperature in kelvin - 273
• °F= 0°C x 9/5 + 32
• Change in state of matter:

  • By changing the temperature
  • By changing the pressure
• Solidification: The process of converting liquids into solids
• Fusion: The process of converting solids into liquids
• Vaporisation: The process of converting liquids into gases (vapours)
• Condensation: The process of converting gases into liquids
• Sublimation: The process of converting a solid into a gas without undergoing the liquid state
• Deposition: The process of converting a gas into a solid without undergoing the liquid state
• examples of sublimates:

  1. Camphor
  2. Iodine
  3. Anthracene
  4. Naphthalene
  5. Ammonium chloride
• The temperature where a solid melts into its liquid form, at normal atmospheric pressure is called its melting point.
• The temperature where a liquids converts into vapors (gaseous form), at normal atmospheric pressure is called its boiling point.
• The heat supplied during the change of state is used to overcome the force of attraction between the particles of solids or liquids and hence the temperature does not rise above. This is called the latent heat.
• 1. Latent heat of fusion: The amount of heat required to change 1kg of solid into liquid, at normal atmospheric pressure, at its melting point, is called the latent heat of fusion.
• 2. Latent heat of vaporization: The amount of heat required to change 1kg of liquid into gas at normal atmospheric pressure, at its boiling point, is called latent heat of vaporization.
• The process by which a liquid converts into its gaseous state at any temperature below its boiling point is called evaporation.
• Factors that affect evaporation:

  1. Surface area: An increase in surface area, an increase in the rate of evaporation
  2. Wind: A n increase in wind speed. an increase in the rate of evaporation
  3. Temperature: The higher the temperature, the higher the rate of evaporation.
  4. Humidity: If humidity is high, the rate of evaporation will be slow and if the humidity is low, the rate of evaporation will increase.
• Particles of liquids keep on evaporating by absorbing the heat from its surroundings and hence make the surroundings cold