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| Question | Answer |
| What type of bond forms between water molecules? | Hydrogen bonding When two water molecules are in close contact, their opposing charges attract each other, forming a hydrogen bond |
| What are the functions of water? | A reactant (e.g. in hydrolysis) A solvent Transporting substances Temperature control Habitat |
| Why are cohesion and adhesion useful? | COHESION= sticking together. Hydrogen bonds are weak, but there are a lot of them, so they stick together in a strong lattice framework ADHESION= sticking to other things Cohesion and adhesion allow water to be drawn up xylem vessels to the tops of the highest trees |
| Why is surface tension useful? | The cohesion between water molecules produces surface tension. As the molecules are exposed to air on one side, they will have less neighbouring water molecules to bond with, and will form stronger bonds with the neighbours they DO have. Surface tension is also responsible for rain |
| Define specific heat capacity | Amount of energy needed to raise the temperature by 1°C |
| Why is a high specific heat capacity useful? | Water has a high SHC as the movement of molecules is restricted by the hydrogen bonds between them. Therefore aquatic habitats have relatively stable temperatures |
| Define latent heat of vaporisation | Amount of energy required to change state |
| Why is a high latent heat of vaporisation useful? | Water has a high LHoV. When it evaporates, water draws thermal energy out of the surface it's on (sweating) |
| Why is a low density useful? | Ice is less dense than water. When ice floats on top of water, it forms an insulating layer. If ice were denser than water, then a pond would freeze from the bottom up, killing all the living organisms within it |
| Why is being a universal solvent useful? | When a chemical dissolves in water, it is free to move about and react with other chemicals. As water is a dipolar molecule, it will attract other charged particles and polar molecules (e.g. glucose) In contrast, non-polar molecules such as lipids will not dissolve in water (as lipids are hydrophobic). This hydrophobic property of lipids gives stability to the cell membrane |
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