Changes of state and particle model

• State the different states of matter in order of density of atoms.

  Least: Gas

  Liquid

  Solid
• Describe the particle arrangement of a solid.

  Tightly packed in a regular arangement, can vibrate in fixed positions
• Describe the particle arrangement in a liquid.

  Close together, within a irregular arrangement. They can flow over each other.
• Describe the particle arrangement of a gas.

  Seperated with no regular arangement, can move around freely.
• What is always conserved when a substance changes state?

  Mass
• How does change of state differ from chemical change?

  In change of state, the material can return to having it's properities if the change is reversed.
• What is sublimation?

  The process of a substance changing directly from a solid to a gas without going through the liquid phase.
• What is evaporation?

  The process of a liquid turning into a gas.
• What is condensation?

  The process of a gas turning into a liquid.
• When water boils in an open pan, why does the mass of the pan of water appear to decrease?

  Some of the water will evaporate and turn into water vapour. This will leave the pan and cause the mass of the pan to decrease. The mass of the whole system remains constant.
• Explain the process involved when a bathroom mirrored mists up?

  Hot water evaporates to form water vapour

  This water vapour lands on a cooler mirror

  The vapour condenses on the mirror and returns to liquid state on the mirrors surface.