Chapter 3 Flashcards
Cohesion
At any moment, all the water molecules are linked by multiple hydrogen bonds, these bonds make water highly structured
o Responsible for transport of water and dissolved nutrients against gravity of plants
Adhesion
the clinging of one substance to another
o Adhesion of water to molecules of cell walls helps counter the downward pull of gravity
surface tension
a measure of how difficult it is to stretch or break the surface of a liquid
o Neatly arranged water molecules are at the surface of water, separating it from air, giving water an unusually high surface tension
o Ex: Overfilling a glass of water, water will stand over the brim
kinetic energy
energy of motion
o The faster a molecule moves, the greater its kinetic energy
thermal energy
-form of kinetic energy
the energy associated with the random movements of atoms or molecules
temperature
measure of the average kinetic energy of molecules in a body of water
heat
the thermal energy in transfer from one body of matter to another
calorie (2 defns)
amount of heat it takes to raise the temperature of 1 g of water by 1°C
• Also is the amount of heat 1 g of water releases when it cools by 1°C
Kilocalorie
(1000 cal), the quantity of heat required to raise the temp. of 1 kg of water by 1°C
Joule
one joule=.239 cal, 1 cal=4.184 J
specific heat
the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1°C
o How well a substance resists change in its temperature when it absorbs or releases heat
• Specific heat of water: 1 cal/ g x °C
Heat of vaporization
the quantity of heat a liquid must absorb for 1 g of it to be converted from liquid to gaseous state
o Water has high heat of vap. To evaporate 1 g at 25°C, you need 580 cal heat (which is a lot of heat/energy).
Evaporative cooling
as liquid evaporates, the surface of the liquid remaining cools down
Solution
a liquid that is a completely homogenous mixture of two or more substances
Solvent
what does the dissolving
Solute
substance which is being dissolved
Aqueous solution
substance dissolved in water, water ‘does the dissolving’
Hydrophilic
has an affinity for water
Exception: Some hydrophilic things can’t dissolve in water. For example, cotton consists of cellulose molecules which have many regions that allow for H bonding. Thus, water adheres to cellulose fibers.
Hydrophobic
do not have affinity for water; nonionic and nonpolar
Ex: Oil consists of nonpolar covalent compounds. Found in cell membranes.
