AP Biology Chapter 2 Flashcards
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| 7288466833 | Matter | - Anything that takes up space and has mass - Composes organisms - Made up of elements | 0 | |
| 7288466834 | Element | - A substance that cannot be broken down to other substances by chemical reactions - 92 naturally occurring elements | 1 | |
| 7288466835 | 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 | |
| 7288466836 | Essential Elements | - Elements that an organism needs to live a healthy life and reproduce | 3 | |
| 7288466837 | Trace Elements | - Elements that are required by an organism in small quantities. - Ex. in vertebrates iodine is an essential ingredient of a hormone produced by the thyroid gland. | 4 | |
| 7288466838 | Toxic Elements | - Some naturally occurring elements are toxic to organisms. - Some species have adapted to environments containing elements that are usually toxic. - Ex. Sunflowers can absorb lead, zinc and other heavy metals in concentrations that would kill other organisms. | 5 | |
| 7288466839 | 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 | 6 | |
| 7288466840 | Subatomic particles | - Compose atoms. - Three relevant kinds: neutrons, protons and elections | 7 | |
| 7288466841 | Proton | - Charge: positive - Location: nucleus - Mass: 1 dalton | 8 | |
| 7288466842 | Electron | - Charge: negative - Location: orbits around the nucleus - Mass: so small that electrons are insignificant when computing the total mass of an atom | 9 | |
| 7288466843 | Neutron | - Charge: electrically neutral - Location: nucleus - Mass: 1 dalton | 10 | |
| 7288466844 | Atomic Nucleus | - The center of an atom - Has a positive charge due to the protons inside of it | 11 | |
| 7288466845 | 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 | 12 | |
| 7288466846 | Mass Number | - Sum of the protons and neutrons in the nucleus of an atom. | 13 | |
| 7288466847 | Atomic Mass | - An approximation of the total mass of an atom. - Same number as the Mass Number. | 14 | |
| 7288466848 | Isotope | - Different atomic forms of the same element. - Same number of protons, different number of neutrons. - Behave identically in chemical reactions. | 15 | |
| 7288466849 | 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. | 16 | |
| 7288466850 | Energy | - The capacity to cause change by doing work. | 17 | |
| 7288466851 | 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. | 18 | |
| 7288466852 | Electrons & Potential Energy | - The electrons of an atom have potential energy because of how they are arranged in relation to the nucleus. - Because negative electrons attract to the positive nucleus, it takes work to move an electron father away from the nucleus. - The farther away an electron is from the nucleus, the greater its potential energy. - An electron's potential energy is determined by its energy level. | 19 | |
| 7288466853 | 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 |  | 20 |
| 7288466854 | Electron Distribution & Chemical Properties | - The chemical behavior of an atom is determined by the distribution of electrons in the atom's electron shells. | 21 | |
| 7288466855 | 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. | 22 | |
| 7288466856 | Valence Shell | - The outermost electron shell. - An atom with a completed valence shell is unreactive because it is stable (inert). | 23 | |
| 7288466857 | 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 | 24 | |
| 7288466858 | Covalent Bond | - The sharing of a pair of valence electrons by two atoms. | 25 | |
| 7288466859 | Molecule | - Composed of 2 or more atoms held together by covalent bonds. | 26 | |
| 7288466860 | Single Bond | - A pair of shared electrons. - Represented by a single line |  | 27 |
| 7288466861 | Double bond | - 2 shared pairs of valence electrons. - Represented by 2 lines | 28 | |
| 7288466862 | Valence | - Bonding capacity of an atom - Usually equals the number of electrons required to complete the atom;s outermost (valence shell) | 29 | |
| 7288466863 | 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. | 30 | |
| 7288466864 | Nonpolar covalent bond | - A bond where the electrons are shared equally because the two atoms have the same electronegativity. - Ex. H2 is nonpolar | 31 | |
| 7288466865 | Polar covalent bond | - Bond where an atom is bonded to a more electronegative atom. - Electrons are not shared equally. |  | 32 |
| 7288466866 | 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. | 33 | |
| 7288466867 | Ion | - A charged atom (or molecule). - Electrons have either been lost or gained. | 34 | |
| 7288466868 | Cation | - Positively charged atom. - An electron has been lost. | 35 | |
| 7288466869 | Anion | - Negatively charged atom. - An electron has been gained. | 36 | |
| 7288466870 | Ionic compounds/salts | - Compounds formed by ionic bonds. - Does not consist of molecules, only elements. | 37 | |
| 7288466871 | Advantages of weak chemical bonds | - Two molecules can adhere temporarily by weak bonds. - Two molecules can come together, respond to one another in some way and then separate. | 38 | |
| 7288466872 | 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. | 39 | |
| 7288466873 | Van deer Walls Interactions | - Individually weak bonds that occur only when atoms and molecules are very close together. - Ex. Geckos can climb up walls because their toes have tiny hairs and there are van der Waals interactions between the hair tip molecules and the molecules of the wall's surface. Because they are so numerous they can support the Gecko's body. | 40 | |
| 7288466874 | Molecular Shape | - Determines how biological molecules recognize and respond to one another with specific. - Complementary molecules bind to each other. - Ex. Because opiates have similar shapes to endorphins, they bind to endorphin receptors in the brain. |  | 41 |
| 7288466875 | 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. | 42 | |
| 7288466876 | Reactants | - Starting materials in a chemical reaction | 43 | |
| 7288466877 | Products | - The elements or compounds produced by a chemical reaction. | 44 | |
| 7288466878 | 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. | 45 | |
| 7288466879 | 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. |  | 46 |
| 7288466880 | Cohesion of Water | - Result of the hydrogen bonds that hold water together. - Contributes to the transport of water & dissolved nutrients. | 47 | |
| 7288466881 | Adhesion | - The clinging of one substance to another. | 48 | |
| 7288466882 | 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. | 49 | |
| 7288466883 | 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. | 50 | |
| 7288466884 | Kinetic energy | - Energy of motion. | 51 | |
| 7288466885 | Thermal energy | - The kinetic energy associated with the random movement of atoms or molecules. - Total thermal energy of matter depends on volume. | 52 | |
| 7288466886 | Temperature | - The average kinetic energy of molecules, regardless of volume. | 53 | |
| 7288466887 | Heat | - Thermal energy in transfer from one body of matter to another. | 54 | |
| 7288466888 | Calorie | - The amount of heat it takes to raise the temperature of 1 g of water by 1degree C. | 55 | |
| 7288466889 | kilocalorie | - (1,000 cal) is the quantity of heat required to raise the temperature of 1 kilogram of water by 1 degree C. | 56 | |
| 7288466890 | 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) | 57 | |
| 7288466891 | 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). | 58 | |
| 7288466892 | 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. | 59 | |
| 7288466893 | Evaporative Cooling | - As a liquid evaporates, the surface of the liquid that remains behind cools down. - "Hottest" molecules leave as gas first. - Contributes to the stability of temperature in bodies of water and keeps organisms from overheating. | 60 | |
| 7288466894 | 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. | 61 | |
| 7288466895 | Solution | - A liquid that is a completely homogeneous mixture of 2 or more substances. | 62 | |
| 7288466896 | Solvent | - The dissolving agent of a solution. | 63 | |
| 7288466897 | Solute | - The substance that is dissolved. | 64 | |
| 7288466898 | Aqueous solution | - Solution where water is the solvent. | 65 | |
| 7288466899 | Hydration Shell | - The sphere of water molecules around a dissolved ion. - Water molecules pull appart compounds by surrounding each ion and separating and shielding them from one another. - To be dissolved by water you must have ionic and polar regions. | 66 | |
| 7288466900 | Hydrophilic | - A substance that has an affinity for water. - Substances can be hydrophilic without actually dissolving (cotton). | 67 | |
| 7288466901 | Hydrophobic | - Substances that repel water. - They are nonionic and nonpolar or otherwise cannot form hydrogen bonds. | 68 | |
| 7288466902 | Molecular mass | - The sum of the masses of all the atoms in a molecule. | 69 | |
| 7288466903 | Mole | - Represents an exact number of objects - 6.02 * 10^23 - A mole of one substance has exactly the same number of molecules as a mole of any other substance. | 70 | |
| 7288466904 | 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+) |  | 71 |
| 7288466905 | Acid | - Substance that increases the hydrogen ion concentration of a solution. - When acids dissolve in water, they donate an additional H+ to the solution. | 72 | |
| 7288466906 | 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+ | 73 | |
| 7288466907 | Strong Acid/Strong Base | - Compounds that completely dissociate when mixed with water. - Hydrochloric acid is a strong acid. - Sodium hydroxide is a strong base. | 74 | |
| 7288466908 | pH | - The pH of a solution is the negative logarithm (base 10) of the hydrogen ion concentration. | 75 | |
| 7288466909 | 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) |  | 76 |
| 7288466910 | 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 |  | 77 |
| 7288466911 | 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). | 78 |