ap bio chapter 3

water is the only substance that naturally exists in…

the 3 forms of matter

what part of the water molecule do electrons spend most time near?

oxygen part of molecule

the oxygen region of a water molecule has what charge

partial - charge

are hydrogen bonds in liquid water strong or weak?

weak

describe the behavior of hydrogen bonds in liquid water

because they are weak they are constantly being broken and reformed

released when hydrogen bonds are broken

heat

give an example of evaporative cooling in humans

only the hottest water molecules in human sweat evaporate- when they do, the skin surface is cooled - an example of evaporative cooling

the 4 life sustaining properties of water

1. cohesive behavior

2. versatility as a solvent

3. expansion when frozen

4. temperature moderation

why do water molecules stay close to one another

due to hydrogen bonding (cohesion)

what happens to the water inside a plant stem when water evaporates from the leaf?

upward pull is exerted on the water, pulling up through stem

define surface tension

how difficult it is to stretch or break a liquids surface

water ____ heat to/from warmer air

absorbs

water ____ heat to/from colder air

releases

how is waters temperature changed when it exchanges heat

water temperature barely changes even when absorbing large amounts of heat (high specific heat)

what is the difference between temperature and thermal energy

temperature is NOT based on volume - thermal energy is

what happens when 2 objects of different temperatures come together

warmer object passes heat to the cooler object until both are the same temped

define heat

thermal energy transfer from one body of matter to anotherw

what does one calorie do to 1g of water

raises its temp by 1 degree C

how many cal in a kilocalorie

1000

specific heat is the amount of heat that is absorbed or lost….

for one gram of a substance to change by 1*C

what can we credit for water’s high specific heat?

hydrogen bonding

what do large bodies of water do in terms of climate fluctuation?

they minimize the effects and keep the range livable

what happens ti water molecules going fast enough to overcome liquid attractive forces?

they vaporize

how does water’s density change from liquid to solid?

it becomes less dense when it freezes

what happens ti water molecules t 0 DEG C

they lock into a crystal structure with 4 bonds w surrounding molecules w

why is water a versatile solvent

its polarity

what’s a hydration shell

water molecules surround ions and shield them from other ions