Water Chapter 3

Water

39 cards   |   Total Attempts: 183
  

Cards In This Set

Front Back
What is the biological medium of life?
Water
How much water is in cells?
70-95% water
What is the main reason Earth is habitable?
Water
What kind of molecule is water?
- a polar molecule- polarity allows water molecules to form hydrogen bonds with each other
What makes water a polar molecule?
- the unequal sharing of electrons and water's V-like shape- means that its overall charge is unevenly distributed- the oxygen region of the molecule has a partial negative charge and each hydrogen a partial positive charge
Polar covalent bond
Answer 6
Oxygen is more electronegative than hydrogen, so the electrons of the covalent bonds spend more time closer to oxygen than to hydrogen
Hydrogen bond
- the slightly positive hydrogen of one molecule is attracted and held together to the slightly negative oxygen of a nearby molecule- weak bonds
Four water properties that facilitate life are what?
- cohesive behavior- ability to moderate temperature- expansion upon freezing- versatility as a solvent
Cohesion
- hydrogen bonds hold water molecules together- helps transport water against gravity in plants
Adhesion
- attraction between different substances, as in between water and plant cell walls- adhesion of water to cell walls by hydrogen bonds helps counter the downward pull of gravity
Cohesion and adhesion in plants
Answer 11
Cohesion and adhesion in plants
Surface tension
Answer 12
- a measure of how hard it is to break the surface of a liquid- related to cohesion- water has a greater surface tension than most other liquids- at the interface between water and air is an ordered arrangement of water molecules, hydrogen bonded to one another and to the water below. This makes water behave as though coated with an invisible film.
How does water moderate air temperature?
- water absorbs heat from warmer air and releases stored heat as cooler air
How is water effective as a heat bank?
Because it can absorb or release relatively large amounts of heat with only a slight change in its own temperature
What is the relevance of water's high specific heat to life on Earth?
Answer 15
- a large body of water can absorb and store a huge amount of heat from the sun in the daytime during summer while warming up only a few degrees- the relatively cool ocean reduces coastal air temperature by absorbing heat