Water Flashcards
Describe latent heat of vaporistation of water and how it accomodates life.
Very low - good for cooling cells
Describe specific heat capacity of water and how it accomodates life.
Very high - good for homeostasis and keeping earth at a stable temperature.
Describe the hydrogen bonding between water molecules
An intermolecular force forms (H bond) between a partially positively charged hydrogen in a water molecule (δ+) and a partially negatively charged oxygen in a different water molecule (δ− )
- H bonds are much stronger than other IM
forces
What is electronegativity?
Means how much an atom “likes” electrons or how high they have an affinity to electrons.
How does electronegativity change across the periodic table?
EN is the highest at the top right, and lowest at the bottom left. There is negligible electron affinity in the middle.
Why is water a dipolar molecule?
It is an overall neutral molecule which possesses at least one negative and positive charge.
Describe how surface tension forms.
At the surface of water, the overall force on molecules is downwards, whereas there is no overall force on molecules submerged. So the surface molecules are more tightly compressed.
Cohesion vs Adhesion
Cohesion - the ability of water molecules to stick together through hydrogen bonding
Adhesion - ability of water moleules to stick to other polar or charged surfaces through hydrogen bonding.
Why does water as a solvent benefit organisms
Metabolic processes occur in soloution in the body
Substances such as glucose can be dissolved in water in the blood to be transported around the organism.
How does bouyancy benefit organisms
Ice is less dense than water, so it floats - allowing organisms to survive under ice.
Most organisms have a density close to that of water, so they do not need to use much energy to float.
What is capillary action?
How water moves through narrow spaces - aided by intermolecular forces e.g. transpiration through xylem.
What is the origin of water on earth + evidence?
Scientists beleive water originated from an astroid made of ice colliding with earth
Evidence - comparing ratio of hydrogen and deuterium on astroids and earth revealed the same ratio.
What is the goldilocks zone?
The range around a star at which a planet can support liquid water.
