AP Biology Chapter 2 Flashcards
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| 14813032267 | Matter | - Anything that takes up space and has mass - Composes organisms - Made up of elements | 0 | |
| 14813032268 | Element | - A substance that cannot be broken down to other substances by chemical reactions - 92 naturally occurring elements | 1 | |
| 14813032269 | Compound | - A substance consisting of two or more different elements combined in a fixed ratio - Has chemical and physical characteristics different from those of its elements - Ex. Water (H20) is a compound that has a 2:1 ratio | 2 | |
| 14813032273 | Atom | - The smallest unit of matter that still retains the properties of an element. - Each element consists of a certain type of atom that is different from the atoms of any other element. - Most empty space | 3 | |
| 14813032274 | Subatomic particles | - Compose atoms. - Three relevant kinds: neutrons, protons and elections | 4 | |
| 14813032275 | Proton | - Charge: positive - Location: nucleus - Mass: 1 dalton | 5 | |
| 14813032276 | Electron | - Charge: negative - Location: orbits around the nucleus - Mass: so small that electrons are insignificant when computing the total mass of an atom | 6 | |
| 14813032277 | Neutron | - Charge: electrically neutral - Location: nucleus - Mass: 1 dalton | 7 | |
| 14813032278 | Atomic Nucleus | - The center of an atom - Has a positive charge due to the protons inside of it | 8 | |
| 14813032279 | Atomic Number | - Number of protons. - All atoms of a particular element have the same atomic number. - If an atom is neutral, the # of protons= # electrons | 9 | |
| 14813032280 | Mass Number | - Sum of the protons and neutrons in the nucleus of an atom. | 10 | |
| 14813032281 | Atomic Mass | - An approximation of the total mass of an atom. - Same number as the Mass Number. | 11 | |
| 14813032282 | Isotope | - Different atomic forms of the same element. - Same number of protons, different number of neutrons. - Behave identically in chemical reactions. | 12 | |
| 14813032283 | Radioactive Isotope | - Isotope where the nucleus decays spontaneously giving off particles and energy. - Decay will lead to a change in the number of protons, and the atom transforms to an atom of a different element. | 13 | |
| 14813032284 | Energy | - The capacity to cause change by doing work. | 14 | |
| 14813032285 | Potential Energy | - Energy that matter possesses because of its location or structure - Matter has a natural tendency to move to the lowest possible state of potential energy. | 15 | |
| 14813032287 | Electron Shells | - Places of high probability of finding an electron. - First shell- lowest potential energy, and so forth - An electron can change its shell by absorbing/ loosing energy. - 1st shell holds 2 electrons, 2nd shell holds 8 electrons |  | 16 |
| 14813032288 | Electron Distribution & Chemical Properties | - The chemical behavior of an atom is determined by the distribution of electrons in the atom's electron shells. | 17 | |
| 14813032289 | Valence Electrons | - The outermost electrons. - Chemical behavior depends mostly on valence electrons. - Atoms with the same number of electrons in their valence shells exhibit similar chemical behavior. | 18 | |
| 14813032290 | Valence Shell | - The outermost electron shell. - An atom with a completed valence shell is unreactive because it is stable (inert). | 19 | |
| 14813032291 | Chemical Bonds | - Bonds between atoms when they either share or transfer valence electrons. - The strongest kinds of chemical bonds are covalent and ionic bonds. - When bonds form, they make fill the atoms valence shell | 20 | |
| 14813032292 | Covalent Bond | - The sharing of a pair of valence electrons by two atoms. | 21 | |
| 14813032293 | Molecule | - Composed of 2 or more atoms held together by covalent bonds. | 22 | |
| 14813032294 | Single Bond | - A pair of shared electrons. - Represented by a single line |  | 23 |
| 14813032295 | Double bond | - 2 shared pairs of valence electrons. - Represented by 2 lines | 24 | |
| 14813032296 | Valence | - Bonding capacity of an atom - Usually equals the number of electrons required to complete the atom;s outermost (valence shell) | 25 | |
| 14813032297 | Electronegativity | - The attraction of a particular atom for the electrons of a covalent bond. - The more electronegative an atom is, the more strongly it pulls shared electrons towards itself. | 26 | |
| 14813032298 | Nonpolar covalent bond | - A bond where the electrons are shared equally because the two atoms have the same electronegativity. - Ex. H2 is nonpolar | 27 | |
| 14813032299 | Polar covalent bond | - Bond where an atom is bonded to a more electronegative atom. - Electrons are not shared equally. |  | 28 |
| 14813032300 | Ionic Bond | - Formed by the attraction of cations and anions. - Electrons are transfered. - Environment affects the strength of ionic bonds. - Dry salt crystal- bonds are very strong. - Salt crystal dissolved in water- bonds are waker because each ion is partially shielded by its interactions with water molecules. | 29 | |
| 14813032301 | Ion | - A charged atom (or molecule). - Electrons have either been lost or gained. | 30 | |
| 14813032302 | Cation | - Positively charged atom. - An electron has been lost. | 31 | |
| 14813032303 | Anion | - Negatively charged atom. - An electron has been gained. | 32 | |
| 14813032304 | Ionic compounds/salts | - Compounds formed by ionic bonds. - Does not consist of molecules, only elements. | 33 | |
| 14813032306 | Hydrogen bonds | - Partial positive charge of a hydrogen atom that is covalently bonded to an electronegative atom allows the hydrogen to be attracted to a different electronegative atom nearby. - A hydrogen bond is the nonequivalent attraction between a hydrogen and an electronegative atom. | 34 | |
| 14813032309 | Chemical reactions | - The making and breaking of chemical bonds, leading to changes in the composition of matter. - Matter is neither created nor destroyed, only rearranged. - Reactions are reversible. | 35 | |
| 14813032310 | Reactants | - Starting materials in a chemical reaction | 36 | |
| 14813032311 | Products | - The elements or compounds produced by a chemical reaction. | 37 | |
| 14813032312 | Chemical equilibrium | - The point at which the reactions offset one another exactly. - This is dynamic: reactions still occur, but with no effect on the concentrations of reactants and products. - Concentrations are stabilized at a ratio. | 38 | |
| 14813032313 | Water's polarity | - Unequal sharing of electrons and water's V- like shape make it a polar molecule. - The oxygen region has a partial negative charge. - Each hydrogen has a partial positive charge - Because of this, the hydrogen of one molecule is attracted to the oxygen of another molecule, forming a hydrogen bond. |  | 39 |
| 14813032314 | Cohesion of Water | - Result of the hydrogen bonds that hold water together. - Contributes to the transport of water & dissolved nutrients. | 40 | |
| 14813032315 | Adhesion | - The clinging of one substance to another. | 41 | |
| 14813032316 | Surface tension | - A measure of how difficult it is to stretch or break the surface of a liquid. - Hydrogen bonds in water give it a very high surface tension. | 42 | |
| 14813032317 | Moderation of temperature by water | - Water moderates air temperature by absorbing heat from air that is warmer and releasing the stored heat to air that is cooler. - Water can absorb/release heat with a small change in temperature. | 43 | |
| 14813032318 | Kinetic energy | - Energy of motion. | 44 | |
| 14813032324 | Specific Heat | - The amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature of 1 degree C. - Aka how well a substance resists changing its temperature when it absorbs/releases heat. - Water has a unusually high specific heat (heat must be absorbed to break hydrogen bonds and released when they form) | 45 | |
| 14813032325 | Evaporation/ Vaporization | - Transformation from a liquid to a gas. - Even at low temperatures, fast molecules can escape (some move faster than others and temperature is an average). | 46 | |
| 14813032326 | Heat of vaporization | - The quantity of heat a liquid must absorb for 1g of it to be converted from the liquid to the gaseous state. - Water has a high heat of vaporization, because hydrogen bonds need to be broken. | 47 | |
| 14813032328 | Frozen Water | - Water is less dense as a solid than as a liquid. - Water freezes because more and more of its molecules are moving too slowly to break hydrogen bonds. - 0 degree C, molecules are locked into a crystalline lattice, and hydrogen bonds keep them far away. - Floating ice is important so that lakes do not freeze solid. | 48 | |
| 14813032329 | Solution | - A liquid that is a completely homogeneous mixture of 2 or more substances. | 49 | |
| 14813032330 | Solvent | - The dissolving agent of a solution. | 50 | |
| 14813032331 | Solute | - The substance that is dissolved. | 51 | |
| 14813032332 | Aqueous solution | - Solution where water is the solvent. | 52 | |
| 14813032334 | Hydrophilic | - A substance that has an affinity for water. - Substances can be hydrophilic without actually dissolving (cotton). | 53 | |
| 14813032335 | Hydrophobic | - Substances that repel water. - They are nonionic and nonpolar or otherwise cannot form hydrogen bonds. | 54 | |
| 14813032338 | Dissociation of Water | - A hydrogen atom leaves its electron behind and a hydrogen ion (H+) is transferred - The water molecule that lost a proton is now a hydroxide ion (OH-) and has a charge of 1- - The proton binds to the other water molecule making it a Hydronium ion (H30+) |  | 55 |
| 14813032339 | Acid | - Substance that increases the hydrogen ion concentration of a solution. - When acids dissolve in water, they donate an additional H+ to the solution. | 56 | |
| 14813032340 | Base | - Substances that reduce the hydrogen ion concentration of a solution. - Some directly accept hydrogen ions (Ammonia) - Some dissociate to form hydroxide ions which combine with hydrogen ions and form water. - Basic solutions have a higher concentration of OH- than H+ | 57 | |
| 14813032342 | pH | - The pH of a solution is the negative logarithm (base 10) of the hydrogen ion concentration. | 58 | |
| 14813032343 | pH scale | - pH declines as H+ concentration increases. - pH less than 7- acidic - pH above 7- basic - When the pH of a solution changes slightly, the actual concentrations of H+ and OH- in the solution change substantially (logs) |  | 59 |
| 14813032344 | Buffer | - A substance that minimizes changes in the concentrations of H+ and OH- in a solution. - Accepts hydrogen ions when they are in excess, and donates them when they have been depleted. - Ex. carbonic acid and bicarbonate buffering system |  | 60 |
| 14813032345 | Acidification | - Burning fossil fuels releases CO2 into the air, and when CO2 dissolves in seawater, it reacts with water to form carbonic acid which lowers ocean pH. - As seawater acidifies the extra hydrogen ions combine with carbonate ions to form bicarbonate ions and reduces the carbonate ion concentration. - This is bad, because carbonate ions are required for calcification by many marine organisms (reef-building corals and animals with shells). | 61 |