Chemistry, 1: The particulate nature of matter

• Solids have fixed shape and fixed volume
• Liquids have no definite shape, but fixed volume
• Gases have no fixed shape and no fixed volume
• In solids, particles are held tightly together in a fixed position particles vibrate about their fixed position as they have energy
• In liquids, particles are held tightly together but have the energy to move around

  It will take the shape of the container it is in
• In gases, particles are further apart and have enough energy to move apart from each other

  Particles are constantly moving, and spreads apart to fill the container they are in
• Heat energy provides particles with enough energy to overcome the forces holding it together
• To turn a substance back into a previous state, cool it down to remove heat energy and particles come closer as they bond again.
• Particles in a liquid have different energies, so some may become a gas faster than others (vapour particles)
• Melting and freezing happens at the same temperature
• Boiling and condensation happens at the same temperature
• During state changes, energy is used up in the process of breaking bonds and making new bonds, therefore there is a net energy loss and no increase in kinetic energies of the particles
• An element is what matter is made from

  Elements cannot be broken down

  Elements are made from one kind of particle
• Atoms are small particles that can combine with other atoms to form molecules
• Molecules are made up of two or more atoms
• Diffusion is the net movement of particles from an area of high concentration to an area of low concentration.
• What happens when you put potassium manganate (VII) crystals in water?

  Particles of crystals gradually move into the water and mixes with it
• What happens when you put a jar of bromine on top of a jar of air?

  Bromine is a red-brown gas that is denser than air

  Bromine gas will spread through both jars
• What happens when ammonia gas meets hydrogen chloride gas?

  A white ring is formed where the gases meet

  Because ammonia particles are lighter, they diffuse faster therefore the white ring is nearer to the HCl