Chapter 3: Water and the Fitness of the Environment
Terms : Hide Images [1]
| 32925485 | polar molecule | atoms that, when combined, have an unequal distribution of electrons; the two ends of this conjunction have opposite charges | |
| 32925486 | cohesion | one of the emergent properties of water; the holding together of hydrogen bonds in order to create a substance | |
| 32925487 | adhesion | the clinging of one substance to another | |
| 32925488 | surface tension | a measure of how difficult it is to stretch or break the surface of a liquid; water has a great amount of this due to the intricate patterns and layers of hydrogen bonds | |
| 32925489 | moderation of temperature | one of the emergent properties of water; water has this effect on air by either absorbing or releasing its heat | |
| 32925490 | kinetic energy | energy of motion | |
| 32925491 | heat | a form of energy; the measure of matter's total kinetic energy, thus dependent somewhat on volume | |
| 32925492 | temperature | a measure of heat intensity that represents the average kinetic energy of the molecules, regardless of volume | |
| 32925493 | calorie | the amount of heat it takes to raise the temperature of 1 gram of water by 1 degree Celsius; conversely, also the amount of heat that 1 gram of water releases when it cools by 1 degree Celsius | |
| 32925494 | kilocalorie | quantity of heat required to raise the temperature of 1 kilogram of water by 1 degree Celsius; 1000 of these = 1 calorie | |
| 32925495 | specific heat | the amount of heat that must be absorbed or lost for 1 gram of that substance to change its temperature 1 degree Celsius | |
| 32925496 | heat of vaporization | the quantity of heat a liquid must absorb for 1 gram of it to be converted from the liquid to the gaseous state; this is caused by hydrogen bonds | |
| 32925497 | evaporative cooling | occurs as a liquid evaporates when the surface that remains behind cools down; occurs because the molecules with the most kinetic energy are the most likely to leave as a gas; this prevents overheating and maintains stability | |
| 32925498 | insulation by ice | one of the emergent properties of water; occurs because the liquid form of water is more dense than the solid form of water (ice) | |
| 32925499 | solvent of life | one of the emergent properties of water; results from solutions that include water | |
| 32925500 | solution | a liquid that is a completely homogenous mixture of two or more substances | |
| 32925501 | solvent | the dissolving agent of a solution | |
| 32925502 | solute | the substance that is dissolved in a solution | |
| 32925503 | aqueous solution | a solution in which water is the solvent; water is versatile as a solvent because of its positive and negative molecular structure | |
| 32925504 | hydration shell | the sphere of water molecules around each dissolved ion in a solution | |
| 32925505 | hydrophilic | any substance that has an affinity for water | |
| 32925506 | colloid | a substance that can be hydrophilic without actually dissolving in water because, instead, they remain suspended in the aqueous liquid of the cells | |
| 32925507 | hydrophobic | any substance that does not have an affinity for water; also, a substance that repels water, perhaps because of its inability to form hydrogen bonds | |
| 32925508 | molecular mass | the sum of the masses of all atoms in a molecule | |
| 32925509 | mole | representative of an exact number (6.02x10^23) of objects | |
| 32925510 | molarity | the number of moles of solute per liter of solution; unit of concentration most often used by biologists for aqueous solutions | |
| 32925511 | hydrogen ion | a single gained proton of a water molecule with a charge of 1+ | |
| 32925512 | hydroxide ion | a lost proton from a water molecule with a charge of 1- | |
| 32925513 | hydronium ion | what forms when a proton lost from water bonds with another water molecule | |
| 32925514 | acid | a substance that increases the hydrogen ion concentration of a solution; donates additional H+ to solutions when dissolved in water | |
| 32925515 | base | a substance that reduces the hydrogen ion concentration of a solution; reduces H+ concentration by accepting H+ ions into itself OR by dissociation to form OH- | |
| 32925516 | pH | a solution that is defined by negative logarithm (base 10) of the hydrogen ion concentration: ___ = -log[H+] | |
| 32925517 | buffers | substances that minimize changes in the concentrations of H+ and OH- in a solution; these allow for a relatively constant pH in biological fluids by accepting H+ ions; most contain a weak acid and its corresponding base | |
| 32925518 | acid precipitation | rain, snow, or fog with a pH lower than 5.2 (uncontaminated rain has a pH of 5.6 because of carbonic acid from carbon dioxide and water); this occurs when water reacts with gases in the air; damages life in lakes and streams and adversely affects soil chemistry |