water

• properties of water

  • solvent
  • high specific heat capacity
  • high latent heat of vaporisation
  • cohesive
  • less dense in solids than in liquid
  • surface tension
  • polar
• hydrogen bonds:

  • each water molecule can form hydrogen bonds with up to four others
  • water has a slight negative and positive charge on each end
• hydrogen bond:

  
• state the name of the bond that holds water molecules together (1)

  hydrogen bonds
• DNA is one of many substances which will dissolve in water. explain why water is a good solvent.(2)

  molecules are polar, this polarity enables water molecules to attract to solute molecules.
• Describe the formation of a hydrogen bond between two molecules of water and explain why water can form these bonds(3)

  The slightly positively charged hydrogen molecule is attracted to the slightly negatively charged oxygen molecule. This creates a hydrogen bond in-between the H+ and O- molecule. Hydrogen bonds happen because of the polarity of water
• Why is the ability of water to act as a solent important for the survival of organisms? (3)

  1. medium for reactions
  2. transport
  3. allows ionic compounds to separate
• Outline the properties of water which make it an ideal habitat for an amphibian-frog (2)

  • density
  • high specific heat capacity
• Explain how properties relating to density of water contribute to the survival of organisms (3)

  • ice is less dense then water so floats
  • ice provides habitats for some species
  • aquatic animals can move
  • floating ice insulates the water below
• What is meant by hydrophilic?

  a molecule that can mix and interact with water
• What is meant by hydrophobic?

  a molecule that can not mix and interact with water