P6

• What is density?

  The mass per unit volume of a substance and a description of how many particles are in a given space
• What is the equation for density?

  Density = mass / volume
• Properties of a solid

  • Strong forces of attraction between particles
  • Arrangement of particles is fixed and regular
  • Low energy and vibrate around a fixed point
• Properties of a liquid

  • Weaker forces of attraction between particles
  • Arrangement is close but they can move
  • More energy than a solid
• Properties of gases

  • Almost no force of attraction between particles
  • Free to move in random directions
  • Have the most energy
• What is Brownian motion?

  Gas particles move around randomly at various constant speeds
• Changing state is physical change as no new substance is formed. It occurs when a system is given enough energy
• Cycle of state changes

  
• What is internal energy?

  The summation of the kinetic energy and potential energy
• What is specific latent heat?

  The energy required to change the state of 1kg of substance without a change of temperature
• What is the equation for specific latent heat?

  Energy (J) = Mass (Kg) x Specific latent heat (J/kg)
• When a substance is changing state, energy is being used to break the bonds, so the temperature remains constant. The constant temperatures are the melting and boiling points
• What is gas pressure

  When gas particles collide with a surface and therefore exert force
• Gas pressure increases when the force is bigger or if the collisions are more frequent
• When gas is sealed in a container, the pressure will increase if the temperature is increased or if the volume is decreased