Terms : Hide Images
| 4926811924 | matter | anything that takes up space and has mass | 0 | |
| 4926811925 | element | any substance that cannot be broken down to any other substance by chemical reactions | 1 | |
| 4926811926 | compound | substance consisting of two or more different elements combined in a fixed ratio | 2 | |
| 4926811927 | example of matter having emerging properties | compound has chemical and physical characteristics different from those of its elements | 3 | |
| 4926811928 | essential element | chemical element required for an organism to survive, grow, and reproduce | 4 | |
| 4926811929 | how many of the 92 essential elements are essential elements | 20-25% | 5 | |
| 4926811930 | what four elements make up 96% of all living matter | Nitrogen Oxygen Carbon Hydrogen | 6 | |
| 4926811931 | what elements make up the other 4% of living matter | Calcium Phosphorus Potassium Sulfur | 7 | |
| 4926811932 | trace element | element indispensable for life but required in extremely minute amounts | 8 | |
| 4926811933 | example of a trace element | iron is needed by all forms of life iodine is needed for function of the thyroid gland | 9 | |
| 4926811934 | what does an iron deficiency cause | goiter causes thyroid gland to grow to abnormal size consuming seafood reduces incidence of goiter | 10 | |
| 4926811935 | atom | smallest unit of matter that retains the properties of an element | 11 | |
| 4926811936 | subatomic particles | neutrons protons electrons | 12 | |
| 4926811937 | neutrons | subatomic particle NO electrical charge found in nucleus |  | 13 |
| 4926811938 | protons | subatomic particle single positive charge found in nucleus | | 14 |
| 4926811939 | electron | subatomic particle single negative charge a LOT smaller mass than protons and neutrons move around nucleus of an atom | | 15 |
| 4926811940 | atomic nucleus | atom's dense central core containing protons and neutrons | 16 | |
| 4926811941 | what forms the "cloud" around the nucleus | the rapidly moving electrons negative charge around nucleu |  | 17 |
| 4926811942 | what keeps the electrons in the vicinity of the nucleus | the attraction between opposite charges | 18 | |
| 4926811943 | dalton | measure of mass used for atoms and subatomic particles SAME as atomic mass unit (amu) | 19 | |
| 4926811944 | masses of neutrons and protons | 1 dalton | 20 | |
| 4926811945 | mass of an electron | 1/2,000 of a neutron or proton ignored when computing the total mass of an atom | 21 | |
| 4926811946 | atomic number | number of protons in the nucleus number of electrons in electrically neutral atom unique for each element designated by a subscript | 22 | |
| 4926811947 | what does it mean when there is on subscript to the left of the element | atom is neutral in electrical charge | 23 | |
| 4926811948 | mass number | total number of protons and neutrons in an atom's nucleus written as a subscript to the left of symbol | 24 | |
| 4926811949 | what is the simplest atom | 1/1 H no neutrons consists of a single proton and electron | 25 | |
| 4926811950 | where is the atoms mass found | in the nucleus electrons do not contribute to mass | 26 | |
| 4926811951 | atomic mass | total mass of an atom | 27 | |
| 4926811952 | isotope | one of several atomic forms of an element same number of protons different number of neutrons differing in atomic mass | 28 | |
| 4926811953 | how many naturally occuring isotopes does carbon have | 3 carbon-12 carbon-13 carbon-14 | 29 | |
| 4926811954 | why do isotopes have the same number of protons | so the element doesn't change | 30 | |
| 4926811955 | how do different isotopes behave in chemical reactions | identically | 31 | |
| 4926811956 | decay | nuclei losing subatomic particles | 32 | |
| 4926811957 | radioactive isotope | isotope that is unstable nucleus decays spontaneously giving off detectable particles and energy | 33 | |
| 4926811958 | what happens when the radioactive decay leads to a change in the number of protons | transforms the atom to another element | 34 | |
| 4926811959 | what uses do radioactive isotopes have | researchers use measurements of radioactivity in fossils to date these relics of past life used as tracers to follow atoms through metabolism | 35 | |
| 4926811960 | can cells use radioactive atoms | YES just as they would use nonradioactive isotopes of the same element | 36 | |
| 4926811961 | how are radioactive tracers used in medicine | diagnostic tools kidney disorders can be diagnosed by injecting small doses of substances containing radioactive isotopes into the blood, measuring the amount of tracer excreted in urine imaging instruments PET scanners that monitor growth of cancers | 37 | |
| 4926811962 | how are decaying isotopes dangerous | radiation of decaying isotopes damage cellular molecule hazard to life | 38 | |
| 4926811963 | the severity of decaying isotope radiation depends on what | the type and amount of radiation an organism absorbs | 39 | |
| 4926811964 | which subatomic particle is involved in chemical reactions | electrons | 40 | |
| 4926811965 | energy | capacity to cause change, especially to do work | 41 | |
| 4926811966 | work | to move matter against an opposing force | 42 | |
| 4926811967 | potential energy | energy that matter possesses as a result of its location or spatial arrangement (structure) | 43 | |
| 4926811968 | where does matter have a tendency to go | move toward the lowest possible state of potential energy | 44 | |
| 4926811969 | what must matter do to restore the potential energy | work must be done | 45 | |
| 4926811970 | what is an electrons potential energy determined by | its energy level further away from the nucleus, more potential energy | 46 | |
| 4926811971 | electron shells | energy level of electrons at a characteristic average distance from the nucleus of an atom | 47 | |
| 4926811972 | can an electron exist between energy levels | NO an electron can only exist at certain energy levels | 48 | |
| 4926811973 | how are shells represented in diagrams | concentric circles | 49 | |
| 4926811974 | where is the first shell located | closest to the nucleus | 50 | |
| 4926811975 | what electrons have the lowest potential energy | electrons in the first shell | 51 | |
| 4926811976 | how can an electron move from one shell to another | by absorbing or losing an amount of energy equal to the difference in potential energy between its position in the old shell and that in the new shell | 52 | |
| 4926811977 | what happens when an electron absorbs energy | it moves to a shell farther out from the nucleus | 53 | |
| 4926811978 | what happens when an electron loses energy | electron falls back to a shell closer to the nucleus | 54 | |
| 4926811979 | how is lost energy released | into the environment as heat | 55 | |
| 4926811980 | what determines the chemical behavior of an atom | the distribution of electrons in the atom's electron shell | 56 | |
| 4926811981 | period | row on the periodic table | 57 | |
| 4926811982 | what does the left to right sequence of elements mean | the left to right sequence of elements in each row corresponds to the sequential addition of electrons and protons | 58 | |
| 4926811983 | how many electrons can the first shell hold | no more than 2 | 59 | |
| 4926811984 | how many electrons can the second shell hold | 8 electrons | 60 | |
| 4926811985 | valence electron | electron in the outermost electron shell | 61 | |
| 4926811986 | valence shell | outermost energy shell of an atom containing the valence electrons involved in the chemical reactions of that atom | 62 | |
| 4926811987 | what happens to atoms with a completed valence shell | it is unreactive will not interact with other atoms | 63 | |
| 4926811988 | inert | chemically unreactive incomplete valence shells | 64 | |
| 4926811989 | chemically reactive | incomplete valence shells | 65 | |
| 4926811990 | where does the reactivity of an atom arise from | the presence of one or more unpaired electrons in its valence shell | 66 | |
| 4926811991 | orbital | the 3d space where an electron is found 90% of the time | 67 | |
| 4926811992 | chemical bond | attraction between two atoms resulting from sharing of outer-shell electrons or the presence of opposite charges on the atoms bonded atoms gain complete electron shells | 68 | |
| 4926811993 | 2 strongest kinds of chemical bons | covalent ionic | 69 | |
| 4926811994 | covalent bond | strong chemical bond in which two atoms share one or more pairs of valence electrons | 70 | |
| 4926811995 | molecule | two or more atoms held together by covalent bonds | 71 | |
| 4926811996 | single bond | single covalent bond sharing of a pair of valence electrons by two atoms | 72 | |
| 4926811997 | how is electron sharing depicted | electron distribution diagram or structural formula | 73 | |
| 4926811998 | structural formula | type of molecular notation in which the constituent atoms are joined by lines representing covalent bonds | 74 | |
| 4926811999 | double bond | double covalent bond sharing of two paris of valence electrons by 2 atoms | 75 | |
| 4926812000 | valence | the bonding capacity of a given atom number of covalent bonds an atom can form | 76 | |
| 4926812001 | electronegativity | attraction of a given atom for the electrons of a covalent bond | 77 | |
| 4926812002 | how are electrons shared between two atoms of the same element in a covalent bond | shared equally because two atoms have the same electronegativity | 78 | |
| 4926812003 | nonpolar covalent bond | type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity | 79 | |
| 4926812004 | how are electrons shared when an atom is bonded to a more electronegative atom | electrons are not shared equally polar covalent bond | 80 | |
| 4926812005 | polar covalent bond | covalent bond between atoms that differ in electronegativity shared electrons are pulled closer to the more electronegative atom making it slightly negative and the other atoms slightly positive |  | 81 |
| 4926812006 | ion | atom or group of atoms that has gained or lost one or more electrons acquiring a charge | 82 | |
| 4926812007 | cation | positively charged ion | 83 | |
| 4926812008 | anion | negatively charged ion | 84 | |
| 4926812009 | ionic bond | chemical bond resulting from the attraction between oppositely charged ions | 85 | |
| 4926812010 | ionic compounds | compound resulting from the formation of an ionic bond does NOT consist of molecules (aka a salt) | 86 | |
| 4926812011 | covalent compound | consists of molecules having a definite size and number of atoms | 87 | |
| 4926812012 | do all salts have equal numbers of cation and anions | NO | 88 | |
| 4926812013 | what affects the strength of ionic bonds | environment (can be dissolved, also salt can have very strong bonds that need to be broken with a hammer) | 89 | |
| 4926812014 | how are most drugs manufactured | as salts they are stable when dry but dissociate (come apart) in water | 90 | |
| 4926812015 | why is the reversibility of weak bonding an advantage | two molecules can come together, respond to one another in some way, and then separate | 91 | |
| 4926812016 | hydrogen bond | weak chemical bond formed when slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule | 92 | |
| 4926812017 | what happens when a hydrogen atom is covalently bonded to an electronegative atom | hydrogen atom has a partial positive charge that allows it to be attracted to a different electronegative atom nearby | 93 | |
| 4926812018 | what are hydrogen's electronegative partners | oxygen nitrogen | 94 | |
| 4926812019 | van der Waals interactions | weak attractions between molecules or parts of molecules that result from transient local partial charges occur with molecules that are very close together | 95 | |
| 4926812020 | result of electrons not always being symmetrically distributed in a molecule | everchanging regions of positive and negative charge that enable all atoms and molecules to stick to one another | 96 | |
| 4926812021 | why can geckos walk up a wall | gecko has thousands of tiny hairs with multiple projections on each toe, maximizes surface contact with the wall van der Waals interactions between the molecules of the foot and those of the wall's surface are numerous despite individual weekness | 97 | |
| 4926812022 | what is the effect of weak bonds | to reinforce the 3D shape of the molecule | 98 | |
| 4926812023 | why is molecular shape crucial | determines how biological molecules recognize and respond to one another with specificity | 99 | |
| 4926812024 | opiates | relieve pain and alter mood by weakly binding to specific receptor molecules on surfaces of brain cells | 100 | |
| 4926812025 | endorphins | signaling molecules made by pituitary bind to receptors relieve pain, producing euphoria | 101 | |
| 4926812026 | chemical reactions | making and breaking of chemical bonds leading to changes in the composition of matter | 102 | |
| 4926812027 | reactants | starting material in a chemical reaction | 103 | |
| 4926812028 | product | material resulting from a chemical reaction | 104 | |
| 4926812029 | what do coefficients indicate | number of molecules involved | 105 | |
| 4926812030 | are chemical reactions reversible | YES indicated by two opposite-headed arrows | 106 | |
| 4926812031 | what factors affect the rate of a reaction | concentration of reactants (greater the concentration of reactant molecules, more frequently they collide with one another and then can react and form products) | 107 | |
| 4926812032 | chemical equilibrium | the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time reactions are still going on does NOT mean equal in concentration, concentrations have stabilized at a particular ration | 108 | |
| 4926812033 | how much of cells are water | 70-95% | 109 | |
| 4926812034 | polar molecule | molecule with an uneven distribution of charges in different regions of the molecule | 110 | |
| 4926812035 | cohesion | linking together of like molecules (often hydrogen bonds) |  | 111 |
| 4926812036 | surface tension | measure of how difficult it is to break the surface of a liquid | 112 | |
| 4926812037 | adhesion | clinging of one substance to another (i.e. water to plant cell walls) | 113 | |
| 4926812038 | transpiration | movement of water up plants H2O from roots reache the leaves through xylem (water conducting cells) adhesion of water to cell walls by hydrogen bonds helps counter the pull of gravity | 114 | |
| 4926812039 | why is water as effective as heat bank | it can absorb or release a relatively large amount of heat with a slight change in its own temperature | 115 | |
| 4926812040 | kinetic energy | energy associated with the relative motion of objects | 116 | |
| 4926812041 | thermal energy | total kinectic energy due to the random motion of atoms and molecules energy in most random form depends on matter's volume | 117 | |
| 4926812042 | temperature | measure in degrees of the average kinetic energy (thermal energy) of the atoms and molecules in a body of matter | 118 | |
| 4926812043 | where is thermal energy passed between two objects of different temperatures | thermal energy passes from the warmer to the cooler object until they are the same temperature | 119 | |
| 4926812044 | how does ice work | absorbs thermal energy from the liquid as the ice melts | 120 | |
| 4926812045 | heat | thermal energy in transfer from one body of matter to another | 121 | |
| 4926812046 | calorie | amount of heat energy required to raise the temperature of 1 g of water by 1 degree (Celcius) amount of heat energy that 1 g of water releases when it cools by 1 degree used to indicate the energy content of food | 122 | |
| 4926812047 | kilocalorie (kcal) | a thousand calories amount of heat energy required to raise the temperature of 1 kg of water by 1 degree | 123 | |
| 4926812048 | joule (J) | unit of energy 1 J = .239 cal 1 cal = 4.184 J | 124 | |
| 4926812049 | specific heat | amount of heat that must be absorbed or lost for 1 g of a substance to change it's temperature by 1 degree | 125 | |
| 4926812050 | does water resist changing its temperature | YES when it does change temperature, it absorbs or loses a large quantity of heat for each degree of change | 126 | |
| 4926812051 | what is the relevance of water's high specific heat to life on Earth | gradually cooling water can warm the air moderate air temperatures in coastal areas stabilize ocean temperatures, creating favorable environment for marine life keeps temperature fluctuations on land and in water within limits that permit life organisms are better able to resist changes in their own temperature | 127 | |
| 4926812052 | evaporation | transformation from a liquid to a gas | 128 | |
| 4926812053 | heat of vaporization | quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to gaseous state | 129 | |
| 4926812054 | evaporative cooling | process in which the surface of an object becomes cooler during evaporation result of the molecules with the greatest kinetic energy changing from the liquid to the gaseous state | 130 | |
| 4926812055 | what does humidity cause | high concentration of water vapor in the air inhibits the evaporation of sweat from the body | 131 | |
| 4926812056 | what happens to water molecules from 4 - 0 degrees | water begins to freeze because molecules are moving too slowly to break hydrogen bonds | 132 | |
| 4926812057 | what is water's greatest density | 4 degrees Celcius | 133 | |
| 4926812058 | what formation does water freeze in | crystalline lattice | 134 | |
| 4926812059 | why does ice float | due to its lower density | 135 | |
| 4926812060 | solution | liquid that is homogeneous mixture of two or more substances | 136 | |
| 4926812061 | what is the most versatile solvent | water because of its polarity | 137 | |
| 4926812062 | solvent | dissolving agent of a solution | 138 | |
| 4926812063 | solute | substance that is dissolved in the solution | 139 | |
| 4926812064 | hydration shell | sphere of water molecules around a dissolved ion |  | 140 |
| 4926812065 | hydrophilic | having a "love" for water | 141 | |
| 4926812066 | hydrophobic | water "hating" nonionic nonpolar | 142 | |
| 4926812067 | molecular mass | sum of the masses of all the atoms in a molecule (sometimes called molecular weight) | 143 | |
| 4926812068 | mole | number of grams of a substance that equals its molecular weight in daltons and contains Avogadro's number of molecules | 144 | |
| 4926812069 | Avogadro's number | 6.02 * 10^23 that many daltons in 1 g | 145 | |
| 4926812070 | why is measuring in moles convenient | easier for scientists in the lab to combine substances in fixed rations of molecules | 146 | |
| 4926812071 | molarity | common measure of solute concentration referring to the number of moles of solute per liter of solution | 147 | |
| 4926812072 | hydrogen ion | single proton with a charge of 1+ | 148 | |
| 4926812073 | what does the dissociation of a water molecule lead to | generation of a hydroxide (OH-) and hydrogen ion (H+) in water | 149 | |
| 4926812074 | hydroxide ion | water molecule that has lost a proton OH- | 150 | |
| 4926812075 | hydronium ion | water molecule that has an extra proton bound to it H3O+ commonly represented as H+ | 151 | |
| 4926812076 | acid | substance that increases the hydrogen ion concentration of a solution | 152 | |
| 4926812077 | base | substance that reduces the hydrogen ion concentration of a solution some bases reduce the H+ concentration by accepting hydrogen ions | 153 | |
| 4926812078 | weak acids | acids that reversibly release and accept back hydrogen ions | 154 | |
| 4926812079 | pH | measure of hydrogen ion concentration equal to -log(H+) and ranging in value from 0 to 14 | 155 | |
| 4926812080 | relationship between pH and H+ concentration | pH declines as H+ concentration increases | 156 | |
| 4926812081 | pH value less than 7 | acidic solution | 157 | |
| 4926812082 | pH value above 7 | basic solution | 158 | |
| 4926812083 | why are the slightest changes in pH harmful | chemical processes of the cell are very sensitive to the concentrations of hydrogen and hydroxide ions | 159 | |
| 4926812084 | buffer | solution that contains a weak acid and its corresponding base minimizes changes in pH when acids or bases are added to the solution | 160 | |
| 4926812085 | ocean acidification | process by which the pH of the ocean is lowered (made more acidic) when excess CO2 dissolves in seawater and forms carbonic acid | 161 | |
| 4926812086 | what is the pH of uncontaminated rain | 5.6 | 162 | |
| 4926812087 | why is precipitation more acidic today | burning of fossil fuels ocean acidification | 163 |
