Water Flashcards
Describe the molecular structure of water
Water is a dipolar molecule that consists of 1 oxygen covalently bonded to 2 hydrogens. Due to the uneven disruption of electrons on this molecule , the oxygen is slightly negative and the hydrogen is slightly positive.
Draw a diagram of 2 water molecules bonded together
What are the 5 properties of water?
1.High specific heat capacity
2.high latent heat of vaporisation
3.cohesive and adhesive
4.good solvent
5.less dense as a solid
How is water a good solvent?
Due to waters polarity ( its unequal charge disruption) it can interact with other polar molecules to dissolve them.
Why does ice float in water? Why is this important?
As water begins to freeze the hydrogen bonds fix the positions of the molecules further apart in to a tetrahedral shape whereas in liquid state the molecules are much closer together. This is important as it creates an insulating barrier so life in water
What is cohesion ?
Cohesion is the sticking together of like molecules . Water is cohesive which allows it to move as one mass; this is how the xylem takes up water to the leaf for the transpiration stream.
How is water adhesive?
Adhesion is the attraction of unlike molecules ( other materials). Water is adhesive due to its polarity. This allows for water to act as a transport medium in plants and animals
How does cohesion produce surface tension and why is it important?
At the surface, hydrogen bonds cannot form above so they form more beside each other making the surface more compact. This creates surface tension which is strong enough to support insects such as pond skaters
Explain capillary action and why is it important
The effect of cohesion and adhesion results in water exhibiting capillary action. This is the process by which water can rise up a narrow tube against the force of gravity. This allows for the transpiration stream in plants
How is water a coolant and why is it important?
Water has a high latent heat of vaporisation which mean large amounts of energy is required to overcome the hydrogen bonds. This helps buffer temperature changes during chemical reactions in eukaryotic/ prokaryotic cells allowing for optimum temps for enzyme action
What is SHC and why is it important for water have have a high SHC?
Water needs 4.18j of heat to raise the temp of 1kg of water 1 degree Celsius. It is high due to hydrogen bonding. It helps maintain a constant temperature and stable environment for aquatic life and enzyme action
