A1.1 Water Flashcards
(19 cards)
Why was water required for the first living organisms?
- effective interaction
- formation of compartments
What is electronegativity influenced by?
- number of protons in the nucleus (positive protons in nucleus attract electrons in shells)
- number of orbital shells (the greater the lower electronegativity)
Which is more electronegative in water Oxygen or Hydrogen?
Oxygen
A difference in electronegativity between 2 atoms result in…
A polar covalent bond
What is cohesion?
When water molecules are attracted to each other by hydrogen bonding, allowing molecules to move together
What is tension?
A force that tends to stretch something
What are the cohesive properties used in nature for?
- movement of water in the xylem
- surface tension
How does surface tension work?
Relatively strong cohesive forces between water molecules which need to be overcome
What is an example of cohesion in plants?
Water moving up the xylem
What is transpiration?
When water evaporates from the leaves
What is adhesion?
Attraction between water and other substances via hydrogen bonds
What is cohesion and adhesion used for in plants?
Capillary action
What is capillary action used for?
- Soil remains moist
- Move water into cell walls
What are some examples of hydrophilic molecules?
Glucose, ions, amino acids, proteins
What are some examples of hydrophobic molecules?
Steroid hormones, plasma membrane & nuclear membrane, certain parts of proteins
What is water important for?
- Medium for metabolism
- Transport
What is high specific capacity?
The amount of energy needed to heat up 1kg of a liquid by 1 degree
What is buoyancy?
Force that counteracts the force of gravity (higher density of liquid water = higher buoyancy)
What is thermal conductivity?
Ability of a substance to transfer heat when there is a temperature difference
