1.1 Water: Flashcards
Why is a water molecule dipole? And what type of bonds does it form?
Because it contains an electronegative ‘O’ atom. This causes the O atom to become partially negative and the H atom to become partially positive.
Water forms hydrogen bonds.
Name each water property… There are 8…
- Solvent
- Metabolite
- High specific heat capacity
- High latent heat of vaporisation
- Cohesion –> high surface tension
- High density
- Transparent
Why is water a good solvent? What is water called ‘universal….’? Why is water important in the xylem & phloem?
Water contains dipoles, thus they attract charged particles - such as ions, and other polar molecules such as gluecose.
Water is a universal solvent
Water is a transport medium due to its solvent properties, it thus allows minerals to be transported in the xylem, as well as sucrose, and amino acids in the phloem.
Why do lipids not dissolve in water?
Because they are non-polar molecules.
Water is a metabolite - explain this through condensation & hydrolysis…
Water is used in many biochemical reactions as a REACTANT.
In hydrolysis water is added to break a bond
In condensation water is eliminated (formed)
Why is a high specific heat capacity of water important for ecosystems?
What bond allows for a high specific heat capacity?
Why does this bond allow this?
Because water requires a high amount of heat energy to increase its temp.
Hydrogen bonds allow a high specific heat capacity.
Because these bonds restirct movement , this in turn resists an increase in kinetic energy, and therefore an increase in temp.
This prevents LARGE FLUCTUATIONS in H2O temp. Thus, organims do not have to adapt, and even enzymes can work efficiently.
Why is a high latent heat of vaporisation good for humans?
It means a large amount of energy is required to convert the state of liquid to vapour.
Heat is used to evaporate vaporise water from sweat off the skin - this is a form of temp. control in humans.
This causes the body to COOL…
How does cohesion arise if individually hydrogen bonds are weak?
How does this allow a constant transpiration stream in the xylem of plants?
Despite individually being weak, in a large quantity, hydrogen bonds are strong - forming a lattice.
It allows the xylem to pull up water - forming a transpiration stream - especially in plants of great heights.
Cohesion allows what other property of water key for pond skaters? Water has the highest surface tension apart from…?
HIgh surface tension arises due to cohesion of water molecules. Water has the highest surface tension of any liquid apart from mercury.
Define cohesion:
It is the attraction of water molecules to each other due to the dipole nature of the molecules themselves. This causes hydrogen bonds between them.
Define high specific heat capacity & high latent heat of vaporistaion:
High specific heat of capacity - Energy required to raise the temp. of 1g substance by 1 degree.
High latent heat of vaporisation - Energy required to convert 1g of a liquid into vapour
Why is ice being a good insulator good for aquatic organisms?
How is ice less dense than water?
Density of water?
Water is denser than air. It is also denser than ice. This is becuase in ice the hydrogen bonds hold the molecules further apart.
Ice being a good insulator means it prevents large bodies of water losing heat and freezing completely. Thus, organisms beneath it can survive.
Water has a high density
Why is water being transparent good for aquatic plants?
Allows for sunlight to reach these plants, and thus photosynthesise effectively.
