Chapter 3 Flashcards
Water
-polar molecule, opposite ends have opposite charges
-polarity allows water molecules to form hydrogen bonds with each other
4 water properties that allow environment for life on earth
-cohesive behavior
-ability to moderate temperature
-expansion upon freezing
-versatility as a solvent
Cohesion
-hydrogen bonds hold water molecules together
-helps transport of water against gravity in plants
Adhesion
attraction between different substances
Surface tension
-measure of how hard it is to break the surface of a liquid
-related to cohesion- top of water is arranged through hydrogen bonds
Moderation of temperature
-absorbs heat from warmer air and releases stored heat to cooler air
-can absorb or release a large amount of heat with only slight change in its own temperature
Kinetic energy
-in anything that moves
E=mv^2/2
e=random movement of atoms=thermal energy
m=mass
v^2= speed of movement
Temperature
average kinetic energy of body of matter
Heat
thermal energy transferred from one body of matter to another
Total thermal energy
proportional to the amount (mass) of the matter
Temperature measurements
C
calorie(cal)= amount of heat required to raise the temp of 1g by 1C
1kcal=1000 cal
Joule(J)=0.239cal
1cal=4.184J
Specific heat
the amount of heat that must be absorbed or lost for 1g of substance to change its temp by 1C
-water resists changing its temp because of high specific heat because of hydrogen bonding (absorbs heat to break hydrogen bonds, releases heat when hydrogen bonds form)
Evaporation
transformation from liquid to gas
Heat of vaporization
the heat a liquid must absorb for 1g to be converted to gas
Evaporative cooling
-as liquid evaporates its remaining surface cools
-helps stabilize temperatures in organisms and bodies of water
