Chapter 6

Front 1

Water

Back 1

-density of liquid water at 4 deg C is 1g per cubic meter

-density of ice is only 0.92 grams per cubic meter

-high heat capacity

-good solvent

Front 2

Hydrologic Cycle

Back 2

-the unending circle of our planet's water supply

Front 3

Subatomic Particles

Back 3

positively charged protons and neutrally charges neutrons in the nucleus of the atom, surrounded by negatively charged electrons

Front 4

Hydrogen bonds

Back 4

-in a water molecule, two atoms of hydrogen and one atom of oxygen are held together by covalent bonds

-the water molecule has electrical polarity.

-relatively weak

-(when molecules of the same substance stick together it is called cohesion)

Front 5

Important properties of water

Back 5

-liquidity

-ice expansion (water expands as it freezes)

-surface tension (due to cohesion, water has extremely high surface tension)

-capilarity

-specific heat

-solvent ability

Front 6

Capillarity

Back 6

-due to water being able to stick to other surfaces easily (adhesion), water is able to climb upward in narrow opening.

-capillarity allows water to circulate upward through rock cracks, soil, and the roots and stems of plants.

Front 7

Specific heat

Back 7

-the amount of energy required to raise the temp of 1 gram of a substance (@ 15 deg C) by 1 deg C. '

-water's specific heat is is 1 calorie/gram or about 4190 joules/kg

Front 8

Phase changes of water

Back 8

-Evaporation, condensation, and sublimation

Front 9

sublimation

Back 9

a process whereby a substance converts either from the gaseous state directly to the solid state, or from the solid state directly to the gaseous state. (sometimes referred to as deposition)

Front 10

latent heat

Back 10

the energy exchanged during the phases of sublimation or any change in the structure of a substance

Front 11

the latent heat of melting

Back 11

the energy required to melt ice, also the energy required when freezing ice

-for each gram of ice 80 calories (335 J) of energy are absorbed when ice melts and 80 cal, are released when water freezes

Front 12

The latent heat of fusion

Back 12

the energy released when water freezes

Front 13

The latent heat of condensation

Back 13

the energy released during condensation

--or each gram of liquid water of 100 deg C, 540 calories (2260 J) of energy are abosorbed as wter vaporizes, and 540 calories of energy are released when water vapor condences

Front 14

The latent heat of evaporation

Back 14

the energy required for vaporization

-ranges from 540 cal to 600 cal depending on the temp of the water

-approx 585 cal (2450 J) when the liquid water is at 20 deg C (68 deg F)

Front 15

Importance of latent heat in the atomosphere

Back 15

whenever evaporation takes place, energy is removed from the liquid to vaporize some of the water, the temp of the remaining liquid is reduced, so in effect, evaporation is a cooling process.

condensation, is a warming process in effect, because latent heat energy must be released.Whenever condensation takes place, energy is released back into the atmosphere.

Front 16

Evaporation

Back 16

-the rate of evaporation depends on the temp of the air and water, the amount of water vapor already in the air, ad whether the air is still or moving

Front 17

water vapor content of air

Back 17

The pressure exerted by water vapor is called the vapor pressure

Front 18

Wind

Back 18

if the air overlying a water surface is almost saturated with water vapor, the rate of evaporation is about the same rate of condensation and so very little further evaporation can take place

-if the air remains calm and the temp doesn't change there is no net evaporation

-if the air is in motion, the water vapor molecules are dispersed widely.

Front 19

Evapotranspiration

Back 19

the process by which plants give up moisture through their leaves, combined with the process of water vapor entering the air from land sources.

Front 20

Potential evapotranspiration

Back 20

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