Particulate Nature of Matter

• Particulate nature of matter

  A model used to explain matter, which is made up of small discrete particles in constant and random motion
• Particulate nature of matter

  • All matter is made up of small discrete particles
  • All particles of one pure substance are identical
  • Particles of all matter are in continuous (constant) and random motion
• Particulate nature of matter

  1. Particles move randomly in all directions at high speeds

  2. Particles vibrate about a fixed position

  3. Particles move at high speed

  4. Particles have almost no attraction between them
• Perfume can be smelled some distance away from the person wearing it


  Particles of the perfume move randomly and spread out
• Physical properties of solids


  • Packed very closely together in an orderly manner (fixed, regular pattern)
• Physical properties of liquids


  • Packed very closely together in a disorderly manner (no fixed, regular pattern)
• Physical properties of gases


  • Move randomly in all directions at high speeds
• Solids have a definite volume but no definite shape
• Liquids have the highest density
• Gases can be compressed
• Gases occupy the least volume
• Brownian motion


  The random movement of particles suspended in a fluid (e.g. smoke/dust particles in air, pollen grains in water) due to their collision with the fast-moving molecules in the fluid
• Brownian motion


  1. Water particles collide with the pollen grain

  2. The pollen grain appears to be moving on its own
• When matter gains or loses thermal energy

  The speed of the particles, the forces between the particles, and the distance between the particles will change
• Expansion


  1. Particles move slightly further apart from one another

  2. Volume of matter increases
• Contraction


  1. Particles move closer to one another

  2. Volume of matter decreases
• When a hot-air balloon is heated

  • The air particles have greater kinetic energy and move faster and further apart
  • The force acting by particles on the internal surface increases
  • The volume of the balloon increases
• The mass of matter does not change during expansion and contraction
• Melting


  1. Solid particles gain more kinetic energy and vibrate more vigorously

  2. Particles overcome the strong forces of attraction and start to slide over one another

  3. Solid changes to liquid state
• Freezing


  1. Liquid particles lose kinetic energy and move much slower

  2. Particles cannot overcome the forces of attraction and move closer together

  3. Liquid changes to solid state
• Boiling


  1. Liquid particles gain more kinetic energy and slide over one another faster

  2. Particles overcome the strong forces of attraction and move randomly at high speeds

  3. Liquid changes to gas state
• Condensation


  1. Gas particles attract one another and move closer together

  2. Gas changes to liquid state
• During change of state, temperature remains constant. Thermal energy is used to overcome the forces of attraction between the particles.
• Water is most dense at 4°C as the water particles are packed the closest together at this temperature.
• As water cools down further to become ice, it expands and the particles move further apart, allowing ice to be less dense than liquid water and float at the surface.
• Diffusion


  The net movement of particles from a region of higher concentration to a region of lower concentration
• Matter is made up of tiny, very lightweight particles called atoms.
• The particles that make up matter are too small to be seen with the naked eye.
• Atoms can join together to form molecules or stay separate as individual atoms.
• Particles have kinetic energy due to their motion.
• Atoms can join together to form molecules or they may remain separate (as in gases).
• Atoms can join together to form molecules or they can stay separate (as elements).
• Compounds are formed when two or more different elements chemically react together.
• Elements are substances which cannot be broken down into simpler substances by chemical reactions.
• Temperature is a measure of how fast the particles are moving.
• Mixtures contain two or more substances which do not chemically react with one another.
• Mixtures contain two or more components that do not react with one another, such as sand and water.
• A pure substance is made from only one type of particle, while a mixture contains two or more types of particles.
• Pure substances include metals, non-metals, acids, bases, salts, sugars, water, air, etc., while mixtures include sand, saltwater, soil, blood, gasoline, milk, etc.
• Mixtures contain two or more elements, compounds, or both mixed together but not chemically combined.