Chapter 3: Water and Life Flashcards
Cohesion
linking together of like molecules, often hydrogen bonds
Adhesion
the clinging of one substance to another,
such as water to plant cell walls by hydrogen bonds
Surface Tension
measure of how difficult it is to stretch or break the surface of a liquid
water has a high surface tension because of hydrogen bonds
Kinetic Energy
the energy associated with the relative motion of objects
Thermal Energy
kinetic energy due to the random motion of atoms.
energy in its most random form
Temperature
a measure in degrees of the average kinetic energy of the atoms and molecules in a body of matter
Heat
thermal energy in transfer from one body to another
Calorie
the amount of heat required to raise the temp of 1g of water by 1 degree C
Solution
a liquid, homogeneous mixture of 2 or more substances
Evaporative Cooling
surface of an object becomes cooler during evaporation
example: sweating
Solute
Substance dissolved in a solution
Ocean Acidification
process by which the pH of the ocean is lowered when excess CO2 dissolves in seawater
(CO2 dissolves and forms Carbonic Acid, aka making the water more acidic)
Aqueous Solution
solution with water as the solvent
Hydrophilic
affinity for water
Hydrophobic
no affinity for water (like repels water)
Hydrogen Ion
a single proton w/ a charge of 1+.
h20-> -OH&H+
Hydroxide Ion
water molecule that lost a proton; OH-
Hydronium Ion
a water molecule that has an extra proton bound to it; H30, commonly referred to as H+
Buffers
solution that contains a weak acid and its corresponding base.
-minimizes changes in pH when acids or bases are added to the solution
Discuss the 4 unique characteristics/qualities of water. List each one, then define.
- Cohesion: water sticks to itself because of hydrogen bonds constantly clinging to each other. This creates surface tension.
- Ability to moderate temp: High specific heat makes water suitable for life, prevents temp fluctuations. Evaporative cooling, cools surface on evaporation.
- Expansion on Freezing: water is densest at 4 degrees Celsius. anything above or below is less dense. While water above 4 degrees floats freely, hydrogen molecules between 0-4 degrees stay far apart (they’re slowed down). So ice expands, and floats.
- Versatility as a solvent: bc of its polarity, water is a universal solvent. non-ionic polar molecules and large polar molecules like protein dissolve in polar regions
How do the qualities of cohesion and adhesion of water allow plants to uptake and distribute water throughout their bodies?
- Hydrogen bonds in H2O cause Cohesion
- Water evaporates from leaves
- Evaporating water (bc of hydrogen bonds) pulls water in stem up to leaves, and in roots up to stem
- The adhesion (by hydrogen bonds again) clinging to the cell walls also helps the water counter the downward pull of gravity
