Ch.3 Water and Life Flashcards
Polar molecule
A molecule with uneven distribution of charges in different regions of the molecule
Cohesion
The linking together of like molecules, often by hydrogen bonds
Adhesion
The clinging of one substance to another, such as water to plant cell walls, by means of hydrogen bonds
Surface tension
A measure of how difficult it is to stretch or break the surface of a liquid
Kinetic energy
The energy of motion
Thermal energy
The kinetic energy due to the random motion of atoms and molecules
Temperature
The average kinetic energy of the molecules in a body of matter, regardless of the volume
What happens when objects of different temperatures are brought together?
The thermal energy passes from the warmer to the cooler object until the two are at the same temperature
Heat
Thermal energy in transfer from one body of matter to another
Specific heat
The amount of heat that must absorbed or lost for 1g of a substance to change its temperature by 1 degree celsius
Why does water have such a high specific heat?
A calorie of heat causes a relatively small change in the temperature of water because much of the heat is used to break the hydrogen bonds before the water molecules can begin moving faster
What happens when the temperature of water drops slightly?
When the temperature of water drops slightly, many hydrogen bonds form, releasing a considerable amount of energy in the form of heat
Vaporization
When molecules move fast enough to overcome the molecular attractions and depart the liquid, they enter into the air as a gas
Why does water have a high heat of vaporization?
Due to the strength of hydrogen bonds, which must be broken before the molecules can exit from the liquid in the form of water vapor
Evaporative cooling
Process in which the surface of an object becomes cooler during evaporation, a result of the molecules with the greatest kinetic energy changing from the liquid to the gaseous state
