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Details Title: Chemistry for Living Description: Exam Two Total Flash Cards: 36 Created: 01/18/2005 14:26:58	To study from this set of flash cards, or to create your own your own study flash cards, register HERE. If you are already a registered user, CLICK HERE.
Cards Term Fossil fuels Definition coal, natural gas, and oil; they are non-renewable sources that will eventually run out Term renewable sources Definition wind, solar power, water, grain (corn), mixtrure of gas and alcohol (ie--Brazil uses sugar cane and turns it into alcohol for fuel Term joule Definition unit for energy Term Law of the Conservation of Energy (or) The First Law of Thermodynamics Definition all energy must be conserved (it can not be created or destroyed) **an exception to this law is nuclear reactions which cause a change in matter Term Combustion Reaction Definition one of the most common energy generated reactions; any fuel (ex--hydrocarbon) will burn in the presence of oxygen. the product will always be CO2 + H2O; CH4 + O2--->CO2 + H2O; this reaction generates heat, thus it is an exothermic reaction (endothermic reactions absorb heat) Term activation energy Definition used to start a reaction Term exothermic reaction Definition more energy is on the reactant side; the rest of energy on the product side is converted to something else (but not less); it involves the breaking and reforming of bonds which release energy (breaks it up) and converts to heat (energy decreases) Term endothermic reaction Definition energy is gained; heat is absorbed Term How to affect reaction rate Definition *increase or decrease the concentration of reactants *use a catalyst which wioll increase the rate of reaction by decreasing activation energy *increase temperature which = an increase in the rate of reaction (molecules will bump into each other more quickly) Term What happens when you add a catalyst to an exothermic reaction? Definition less activation energy is needed; the reaction is sped up (reaction rate increases) Term Water on the Earth is made up of... Definition 97.4%=Oceans * 2.59%=ice caps, glaciers, ground water * >.1% is lakes, rivers, the atmosphere Term solvent Definition has the ability to dissolve something else (ex of a solvent is water, H2O Term solute Definition something that can be easily dissolved by water (ie-lemonade mix) Term Dilution Definition by dilution, H2O reduces the concentrations of pollutants to safe levels and/or by carrying them away Term Unique Properties of H2O Definition *very high specific heat (can hold a lot of heat and carry it away to something else) *expands when it freezes *ability to evaporate (vapor/gas) *ability to be displaced *is more dense in liquid form *great solvent *neutral pH *used as a standard *is a liquid instead of a gas at room temp. (low molecular weight--18). Term nonpolar covalent bonds Definition when there is an equal sharing of electrons (ie--Cl2) Term polar covalent bonds Definition when a shared pair is drawn to one atom more than the other (unequal sharing of electrons) Term electronegativity Definition the attraction for a shared pair of electrons; it increases from left to right in a row on the periodic table, and from bottom to top in a column, it increases--ie F (fluorine) is the most electronegative element. Term shared electrons Definition electrons furthest away from the nucleus are the ones being shared Term Fluorine v. Iodine Definition F--has fewer electrons, so nucleus attracts own electrons as wel as electrons of other atoms; I--has more electrons which shield positivity of the nucleus for any other electrons Term (water) Purity Definition *measuring concentration--% refers to parts per 100 (pph); ppm=parts per million; ppb=parts ber billion Term M=molarity Definition moles of solution Term Avogadro's # Definition is equal to 6.023x10^23 atoms or molecules; Term molar mass (molecular weight) Definition 1 mole=avogadro's #=molar mass (ie: CO2-->molar mass=44g=6.02x10^23 molecules of CO2=1 mole of CO2) Term Find the molarity of 10g of CO2 Definition 10g of CO2 x 1 mole/44g=___moles Term H bonding Definition though it is only 1/10 as strong as other bonds, it is a weak bond, but it causes water molecules to stick together; Term ionic bond Definition when there is a transfer of electrons (ie NaCl--Na is +1 and Cl is -1); Term cations Definition positive charge (metals) Term anions Definition negative charge (nonmetals) Term ionic compound Definition made up of a metal and nonmetal; it must be neutral Term polyatomic ions Definition more than one atom joined to another atom w/ a charge (ie--NaOH; (NH4)3PO4 Term what happens when NaCl is dissolved in water? Definition positive parts of H2O (H) surround Cl and negative parts of H2O (O) surround Na; *water is a polar covalent molecule that associates itself with these ions* Term ionic and water Definition ionic compounds WILL dissolve in water (ie--NaCl) Term like dissolves like Definition NH3 is a polar bond and polar molecule, and so is H2O, therefore it will dissolve b/c polar dissolves polar; anything like water will dissolve in it--water and something nonpolar will not dissolve (ie-water and oil) Term why does water dissolve sugar? Definition b/c sugar is made of C12, H22, and O11; hydrogen bonds will be formed and thus O on H2O will attract to H on the sugar molecule and H on H2O will attract to O on sugar molecule. Term concentration Definition it is the ratio of ingredient to water or solute to solvent; can be expressed in ppm, ppb, % (parts per hundred); most commonly used in lab is molarity which is moles per Liter.