P1

• Describe the solid state of matter

  - Strong forces of attraction between particles that hold them in fixed positions in a regular lattice arrangement.

  - The particles do not move from their positions, so they keep a definite shape and volume.

  - The particles vibrate around fixed positions: changes in temperature affect the speed of these vibrations.

  
• Describe the liquid state of matter

  - There is some force of attraction between the particles, they are free to move past each other, but tend to stick together.

  - Liquids don't keep a definite shape, but do keep the same volume.

  - The particles are constantly moving with random motion: changes in temperature affect the speed of these vibrations.

  
• Describe the gas state of matter

  - There is next to no force of attraction between particles, they are free to move, travel in straight lines, and only interact after collisions.

  - Gases do not keep a definite shape or volume and will always fill a container. They exert always exert a pressure on the walls they collide with.

  - The particles move constantly with random motion: changes in temperature affect the speed of these vibrations.

  
• What did Dalton do?

  John Dalton suggested that all matter is made from atoms. he believed that atoms were tiny solid balls. His model explained:

  - all atoms of an element are identical

  - different elements contain different types of atom

  Due to the time period, technology was not advanced, this prevented Dalton from doing further research.

  
• What did Thomson do?

  J.J. Thomson discovered the electron during experiments that showed 'cathode rays' changed direction in electric and magnetic fields. Thomson's model of the atom had to make sense of two things:

  - atoms contain electrons

  - atoms are neutral overall

  His plum pudding model he suggested that atoms are spheres of positive charge with electrons dotted around inside.

  
• What did Rutherford do?

  He conducted the gold foil experiment with two of his students. In this experiment the:

  - fired positively charged alpha particles at an extremely thin sheet of gold.

  - they expected most of the particles to pass straight through or be slightly deflected at most, due to the positive 'pudding' of the atom.

  - however, they witnessed that although most passed through, some deflected more than expected, and some deflected straight back.

  - this proved J.J. Thomson's model incorrect.

  Instead, Rutherford came up with the nuclear atom, where there's a tiny positively charged nucleus in the centre of the atom surrounded by a 'cloud' of negative electrons.

  
• What did Bohr do?

  Bohr suggested that electrons can only exist in fixed orbits, or shells, and not anywhere in between. Each shell has a fixed energy.

  
• What is density and it's formula?

  Density is a measure of the 'compactness' of a substance.

  
• Describe the practical for density

  REGULAR:

  1. Find volume by measuring sides (length x width x depth) (in metres)

  2. weigh the object using a scale (in kg)

  
  

  IRREGULAR:

  1. weigh the object using a scale (in kg)

  2. fill a Eureka can with water and make sure the spout is in line with a measuring cylinder (which can measure the displaced water)

  3. place the irregular shaped object into the water and it will cause the water to be displaced

  4. this means that an amount of water will fall through the spout and into the measuring cylinder

  5. measure the volume of water displaced using the reading on the measuring cylinder
• What is meant by specific heat capacity?

  The specific heat capacity of a substance is the change in energy in the substance's thermal energy store needed to raise 1kg of that substance by 1C
• What is the formula for specific heat capacity?

  Energy transferred (J) = mass (kg) x specific heat capacity (J/kgC) x temperature change (C)

  
• What is meant by specific latent heat?

  The specific latent heat of a change in state of a substance is the change of energy in the thermal energy store when 1kg of the substance changes state without changing its temperature
• What is the formula for specific latent heat?

  Energy (E) = Mass (m) x Specific Latent Heat (L)

  
• What is pressure?

  Pressure is the result of a force distributed over an area

  
• How does temperature affect pressure?

  As a gas in a sealed container is heated, energy is transferred to the kinetic energy stores of the gas causing them to move faster. Hence, they hit the walls of the container harder and more often, creating more pressure, and vice versa.
• What is atmospheric pressure?

  Atmospheric pressure is the pressure exerted by the weight of the atmosphere