Water 💦 Flashcards
Refer to bonds
Why is water dipolar?
Due to uneven distribution of electrons of the covalent bond.
Unshared negative electrons of the oxygen leaves it with a slightly negative charge.
Oxygen is delta negative whereas the hydrogen is delta positive.
Describe the molecular structure of water
Contains two hydrogen atoms and an oxygen atom which are bonded through a covalent bond (sharing of electrons).
What property of water helps ice float?
- Water is more dense than ice causing it to float.
- In a liquid state, the hydrogen bonds constantly form and reform —> more compact.
In solid state, hydrogen bonds are fixed in a tetrahedral structure —> further apart.
Why is the density of water important for organisms
- Creates an insulating layer for aquatic life/ maintains stable temperature.
Define cohesion
- When **water molecules bind/stick to other water molecules **because they are polar.
Why is cohesion important for organisms?
- At the surface, there are less hydrogen bonds between water molecules, causing them to become compact.
- Produces **surface tension **which provides a habitat for animals such as pond skaters.
Define adhesion
- When waters molecules bind/stick to other substances.
Why is adhesion important?
Needed in capillary action as water molecules bind with the walls of tube. Used as a transport medium such as the transpiration stream.
Why is water a good coolant?
Has a hight latent heat of vaporisation as lots of energy to needed break hydrogen bonds.
Good for organisms as heat can evaporate.
Energy required to break hydrogen bonds comes from thermal energy stores, making it a cooling effect for plants/animals.
Why is a high specific heat capacity important for organisms?
Lots of energy required for temperature to increase.
Acts as a buffer for temperature fluctuations and maintains constant habitat for organisms.
Enzymes do not denature.
What is specific heat capacity?
Energy required to raise the temperature of 1kg a substance by 1C.
Why is water a good solvent?
Polar so can transport ions across the body.
Why is water being transparent good for organisms?
Water is transparent meaning sunlight can pass through which is needed for aquatic plants so they can photosynthesise.
