AP Biology Chapter 2 Vocab
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| 458618807 | compound | a substance that consists of two or more elements in a fixed ratio | 1 | |
| 458618808 | trace elements | required by an organism but only in minute quantities; ex. Iron (Fe) | 2 | |
| 458618809 | neutrons | they are electrically neutral; weights about 1.7*10^-24 grams per particle, close to 1 dalton | 3 | |
| 458618810 | electron | can be visualized as forming a cloud of negative charge around the nucleus; one unit of negative charge; 1/2,000 the mass of a neutron/proton | 4 | |
| 458618811 | proton | one unit of positive charge; weights about 1.7*10^-24grams per particle, close to 1 dalton | 5 | |
| 458618812 | atomic nucleus | a dense core packed with neutrons and protons | 6 | |
| 458618813 | dalton | used to measure the masses of subatomic particles, atoms, and molecules | 7 | |
| 458618814 | atomic number | the number of protons (and electrons) is the element's _____ | 8 | |
| 458618815 | mass number | the sum of the number of protons and the number of neutrons in the nucleus of an atom; an approximation of the total mass of an atom | 9 | |
| 458618816 | atomic mass | the total mass of an atom | 10 | |
| 458618817 | isotopes | two atoms of the same element that differ in the number of neutrons | 11 | |
| 458618818 | radioactive isotopes | has many applications in biological research; can be used to trace atoms through metabolic processes; also used to diagnose disorders | 12 | |
| 458618819 | energy | the ability to do work | 13 | |
| 458618820 | potential energy | the energy that matter stores because of its position or location | 14 | |
| 458618821 | kinetic energy | energy in motion | 15 | |
| 458618822 | valence electrons | electrons in the valence shell | 16 | |
| 458618823 | valence shell | the chemical behavior of an atom depends mostly on the number of electrons in it outermost shell, the ________ | 17 | |
| 458618824 | orbital | the space in which the electron is found 90% of the time; it can hold a maximum of 2 electrons | 18 | |
| 458618825 | covalent bond | formed when two atoms share a pair of valence electrons | 19 | |
| 458618826 | molecule | two or more atoms held together by covalent bonds | 20 | |
| 458618827 | single bond | H—H is the structural formula for the covalent bond between two hydrogen atoms; the line represents a _____, a pair of shared electrons | 21 | |
| 458618828 | double bond | two oxygen atoms can form a molecule by sharing two pairs of valence electrons, these atoms form a ________ | 22 | |
| 458618829 | electronegativity | the attraction of an atom for the shared electrons of a covalent bond | 23 | |
| 458618830 | nonpolar covalent bond | if electrons in a covalent bond are shared equally, then this is a ______ | 24 | |
| 458618831 | polar covalent bond | when two atoms that differ in electronegativity bond, they do not share the electron pair equally and they form a _____ | 25 | |
| 458618832 | ion | two atoms of the same element that differ in the number of electrons, which gives it a charges | 26 | |
| 458618833 | cations | atoms with a positive charge | 27 | |
| 458618834 | anions | atoms with negative charges | 28 | |
| 458618835 | ionic compounds/salts | compounds formed by ionic bonds | 29 | |
| 464208833 | cohesion | water molecules tend to hydrogen bond to other water molecules. what property is this? | 30 | |
| 464208834 | cohesion and adhesion | this property aids the movement of fluids up the vascular tissue of plants against the pull of gravity? | 31 | |
| 464208835 | adhesion | water molecules tend to hydrogen bond to non-water molecules. what property is this? | 32 | |
| 464208836 | surface tension | a great affinity for bonding to each other at the interface between air and water. what property is this? | 33 | |
| 464208837 | surface tension | this property contributes to water's tendency to fall as drops of rain, instead of more potentially damaging sheets of water. what property is this? | 34 | |
| 464208838 | specific heat | it takes a relatively large amount of heat to raise the temperature of 1 gram of a substance 1 degree Celsius. what property is this? | 35 | |
| 464208839 | specific heat | water tends to absorb heat from air that is warmer and release it into air that is cooler. it helps moderate temperatures on Earth; also bodies of water can resist quick changes in temperature so aquatic environments tend to be thermally stable. what property is this? | 36 | |
| 464208840 | 4 degrees Celsius | when is water the densest at? | 37 | |
| 464208841 | ice | what floats? | 38 | |
| 464208842 | ice | it insulates the water below | 39 | |
| 464208843 | ice; cools; 4; up; oxygen; nutrients; spring | ___ does not sink and crush organisms in the water; as water ____ in the fall to ___ degrees Celsius, it sinks, forcing bottom water ___ to the surface; this distributes ____ to the bottom and circulates ____ to the surface. also occurs in the _____ | 40 | |
| 464208844 | heat of vaporization | requires large amounts of heat for 1g of a substance to change from the liquid to the gaseous state | 41 | |
| 464208845 | heat of vaporization | as molecular motion increases, the hydrogen bonds holding the molecules together are broken and vapor can leave the liquid. what property is this? | 42 | |
| 464208846 | heat of vaporization | this property makes water a good coolant for organisms, removing large quantities of heat as sweat evaporates. what property is this? | 43 | |
| 464208847 | solvent | water is a very effective ______ | 44 | |
| 464208848 | solvent | it dissolves most polar substances; they are attracted to the polar ends of the molecules (hydrophilic) | 45 | |
| 464208849 | solvent | dissolving occurs when spheres of water molecules called hydration shells form around particles being dissolved, separating them in space. what property does this describe? | 46 | |
| 464208850 | dissociate | 1 or 2 of each 50 million or so water molecules comes apart spontaneously into a H+ (hydrogen) or OH- (hydroxide) ion, what property is this? | 47 | |
| 464208851 | acidic | if the pH is in a range of 1-6, what is it, acidic or basic? | 48 | |
| 464208852 | basic | if the pH is in a range of 8-14, what is it, acidic or basic? | 49 | |
| 464208853 | 7 | what is neutral number on the pH scale? | 50 | |
| 464208854 | acid rain | it is caused by chemicals released when fossil fuels are burned combining with water in the atmosphere; it depletes minerals in the soil as it dissolves and washes them away | 51 | |
| 464208855 | power of hydrogen | the measurement of H+ concentration in a solution is called ______ | 52 | |
| 464208856 | acid | a(n) ____ is a substance that increases the concentration of H+ in a solution | 53 | |
| 464208857 | base | a(n) _____ will decrease the concentration of H+ in a solution by either accepting a H+ ion or by adding OH- to the solution | 54 | |
| 464208858 | acid | the lower the number the stronger the _____ | 55 | |
| 464208859 | base | the higher the number the stronger the _____ | 56 | |
| 464208860 | negative logarithm | the pH of a solution is defined as the _______ ______ (base 10) of the hydrogen concentration | 57 | |
| 464208861 | buffers | substances that minimize changes in pH of biological systems | 58 | |
| 464208862 | buffers | they either accept H+ when H+ concentration becomes too high or more acidic or donate H+ when the H+ declines or becomes too basic | 59 |
