Bio Test
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83 terms
Terms | Definitions |
|---|---|
 pH scale | a scale from 0-14 that helps in determining acids and bases |
| atom | the smallest unit of an element that retains all of its properties |
| atom | smallest unit; cannot be divided |
| atom | carries small particles called electrons |
| electrons | subatomic particles that carry negative electrical charges |
| decreases | as the number of hydrogen atoms goes up, the number on the pH scale ___. |
| acid | something with a pH < 7 |
| base | something with a pH > 7 |
| neutral | something with a pH = 7 |
| neutral | the number of hydrogen atoms is equal to the number of hydroxide atoms |
| water dissociates | about 1/500 million water molecules will come apart to form hydrogen & hydroxide |
| ionization | when non ionic compounds like water dissociate to form ions; a vital process in living cells |
| logarithmic | the pH scale is ____. this means that a change of 1 unit on the pH scale represents a ten fold change on the number of hydrogen/hydroxide ions |
| strong | 11-14 = ___ base |
| weak | >7 <11 = ___ base |
| weak | >3 <7 = ___ acid |
| strong | 0-3 = ___ acid |
| acid | solid, tastes SOUR, corrosive, neutralizes BASES, reacts with pH indicator, conducts electrical currents |
| base | solid, tastes BITTER, corrosive, neutralizes ACIDS, reacts with pH indicator, conducts electrical currents, slippery |
| neutralization | when acid and bases combine to form salt |
| lake | acid rain studies are done to determine the effects of pollution on __ populates and other aspects of living systems |
| reproduce, survive | research has revealed that one complication of an acidic lake is that fish can't ____ and insects can't ___. |
| higher | one interesting outcome observed by the researchers was that the pH level for "die off" was __ than expected |
| toxin | one observed explanation for this was that at the more acidic pH an algae population bloomed and created a ___ that killed off the fish |
| lower | research on the experimental lake areas has led to industry being legislated to __ their emission standards |
| nitric acid | lake research also has revealed that __ __ is an important factor in acid rain and its effects on lakes |
| recover | most encouraging is that researchers have determined that lakes can ___ if emission levels contributing to acid rain are controlled |
| bonds | connections between atoms |
| covalent | ___ bonds share electrons |
| atomic number | the number of protons that identifies the atom |
| atomic mass number | the mass of protons and neutrons expressed in a.m.u.'s |
| atomic mass units | AMU = |
| periods | horizontal rows on the periodic table |
| families | vertical columns on the periodic table |
| periodic law | ____ _ states that when elements are arranged in order based on the number of protons, similarities in their properties will occur in a regular pattern |
| covalent bonds | formed between atoms that share electrons easily, like carbon |
| octet rule | 8 electrons in the outer energy level renders an atom unreactive (stable), except Helium which is non reactive with 2 electrons |
| stability | atoms seeking ____ will do this in one of two ways: form ions or become involved in bonding |
| ion | atom that has lost or gained electrons resulting in a positive or negative charge on the atom |
| anion | negatively charged ion |
| cation | positively charged ion |
| oxidation | ____ refers to the loss of electrons |
| oxidation numbers | ____ __ help to predict bonding patterns and ion formation for specific atoms (elements) |
| covalent bonds | formed between atoms that share electrons easily, like carbon |
| shared | Electrons in covalent bonds are "__" |
| electronegativity | Because of ________, atoms involved in covalent bonding do not always share electrons equally |
| electronegativity | ________ refers to an atom's attraction to its own electrons and electrons in general. |
| nonpolar | a compound that has mostly covalent bonds with electrons that are evenly distributed around the molecules that are sharing the electrons, like methane |
| polar | molecules in which electrons are unevenly shared, like water. |
| ionic bonds | bonded atoms that don't share electrons |
| opposite | ionic bonds are formed between atoms of ___ negativities |
| hydrogen bonds | very weak bonds; occurs when a hydrogen atom in one molecule is attracted to the electrostatic atom in another molecule |
| oxygen, nitrogen | ___ and ___ are VERY important to the molecules of life |
| oxygen, nitrogen | ___ and ___ are highly attracted to electrons so they dissolve in polar water |
| electron cloud model | Electrons move rapidly (like fan blades) forming an electron-cloud (region) |
| orbitals | spaces that are occupied by 2 electrons; The region in an atom where electrons are "likely" to be found |
| shell | Within the atom, there are different amounts of energy in the electrons, within a particular energy level, or _ |
| seven | there are __ different shells |
| 2 | the first energy level in an atom has _ electrons |
| 8 | the second energy level in an atom has _ electrons |
| 18 | the third energy level in an atom has __ electrons |
| 32 | the fourth energy level in an atom has __ electrons |
| subshells | the shells of an atom are divided into... |
| s, p, d, f | the subshells names are _, _, _, and _ |
| 1, 2 | subshell s has _ orbital and can hold up to _ electrons |
| 3, 6 | subshell p has _ orbitals and can hold up to _ electrons |
| 5, 10 | subshell d has _ orbitals and can hold up to _ electrons |
| 7, 14 | subshell f has _ orbitals and can hold up to _ electrons |
| neutral | a water molecule is __ |
| negative, positive | in water molecules, the oxygen end has a slight ___ charge because it is at one end while the hydrogen atoms have a ___ charge because they are at the other end |
| hydrogen bond | a bond formed between molecules that is only strong because of the amount of bonds there are |
| cohesion | an attraction between molecules of the same substance |
| adhesion | an attraction between molecules of different substances |
| hydrogen bonding | water is cohesive due to ___ __ |
| capillary action | the rise of water in a narrow tube against the force of gravity is called... |
| drawing water out | capillary action affects plants by ___ __ _ of the roots of a plant and up into its stems and leaves |
| element | a pure substance that consists entirely of one atom and cannot be broken down by any means into another substance |
| compound | a substance formed by the chemical combination of two or more elements in definite proportions |
| molecule | the smallest unit of most compounds; it results when atoms are joined together by covalent bonds |
| ion | atom that has lost or gained electrons resulting in a positive or negative charge on the atom |
| isotope | one of multiple forms of an element having the same atomic number but a different atomic mass (differing in the number of neutrons) |
| buffer | chemical systems that neutralize small amounts of either an acid or base added to solution |
| carbonic acid buffer system | chemical equilibrium between carbonic acid and bicarbonate ion acts as a pH regulator in the blood |
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