(a) States of Matter

• Particles in a solid are close together and vibrate around fixed positions because of strong forces of attraction between particles
• Particles in a liquid are close together but able to slide past each other as forces of attraction are weaker
• Particles in a gas move randomly and quickly as they are very far apart and have very weak forces of attractions
• Why can’t solids be compressed?

  Particles in a solid are unable to move and have no spaces between them so it’s rigid and maintains a fixed shape and volume
• Why do liquids have a fixed volume but no fixed shape?

  Liquid particles can move over each other so they can flow and take shape of a container causing no fixed shape but volume
• Why can gases be compressed?

  Gas particles are far apart with spaces and they quickly move randomly so there is no fixed shape or volume
• A solid to liquid is known as melting, liquid to gas is known as evaporation, gas to liquid is known as condensation, liquid to solid is known as freezing, solid to gas is known as sublimation, gas to solid is known as deposition
• Explain how a solid changes matter into a liquid

  When a solid is heated up, particles absorb energy and vibrate more. Particles get further apart and bonds break between particles causing it to become liquid
• Explain how a liquid changes to a gas

  When a liquid heats up, intermolecular forces break and particles evaporate by turning into a gas
• Describe how a gas changes into a liquid

  When particles lose energy to surroundings, they get close together and intermolecular forces reform which results in a liquid forming
• Describe how a liquid changes into a solid

  When liquids transfer more kinetic energy, particles lose more energy and bonds reform between particles so a solid is formed
• What are the differences between evaporation and boiling?

  Evaporation happens on the surface of a liquid while boiling happens throughout a liquid. Boiling has a specific temperature while evaporation does not
• Define the meaning of diffusion

  The movement of particles from an area of high concentration to an area of low concentration
• What is meant by solute?

  A substance that dissolves in a solvent to form solutions
• What is meant by solvent?

  A substance which dissolves other substances
• What is meant by solution?

  The mixture formed when a solute is mixed in a solvent
• What is meant by saturated solution?

  A solution with a maximum concentration of solute dissolved in a solvent at a given temperature
• A soluble substance is one that dissolves; an insoluble substance is one that does not dissolve
• What is meant by solubility?

  A measure of how much substance is dissolved in a given volume of liquid
• In solubility, as temperature increases…

  Solids become more soluble while gases become less soluble
• In solubility, as pressure increases…

  Gases become more soluble
• Solubility is always expressed in g per 100 g of solvent