Both have extremely low boiling points? Combine to form water, which shows that properties of compounds are generally very different from the properties of the elements that compose them ? Hydrogen is an explosive gas, oxygen natural component of air (not flammable but used in combustion)? Anions and cations formed, oppositely charged atoms attract? In solid form composed of lattice (regular 3D array of alternating cations and anions)? Ionic bonds - occur between metals and nonmetals, involve transfer of electrons from one atom to another ? Electron attracts the positive charges of both protons? Covalent bonds - occur between two or more nonmetals, sharing of electrons? Chemical bonds - interactions between electrons and protons? Empirical - gives relative number of atoms of each element in compound? Molecular formula - gives actual number of atoms, always whole number multiple of empirical? Structural formula - lines represent covalent bond, shows how the atoms are connected or bonded to each other ? Chemical formula - indicates the elements present in the compound and the relative number of atoms or ions of each ? Carbon = black, hydrogen = white, nitrogen = blue, oxygen = red? Ball and stick model - represent atoms as balls and chemical bonds as sticks? Space filling molecular model - fills space between them to more closely represent our best estimate for how a molecule might appear if scaled to a visible size ? Models? Atomic elements - exist in nature with single atoms as their base units (most elements are)? Molecular elements - do not normally exist in nature with single atoms as their base units, 2+ (eg. Diatomic or polyatomic) ? Molecular compounds - usually composed of two or more covalently bonded nonmetals? Smallest electrically neutral collection of ions? Basic unit of ionic compound = formula unit? Ionic bonds are nondirectional, no one specific cation pairs with a specific anion? Ionic compounds - composed of cations and anions bound together by ionic bonds? Polyatomic ion - ion composed of two or more atoms? Common names - can only be learned through familiarity (eg. Table salt)? Systematic names - what we'll use? Cation + anion-ide? Cation(charge) + anion-ide? If variable cation:? Binary compounds - contain two elements? Oxyanions - anions containing oxygen and another element? Add to end of first compound name with prefix (eg. Heptahydrate)? Hemi- (prefix) is 0.5? Water = waters of hydration? Hydrates - contain specific number of water molecules associated with each formula unit? (prefix)(name of first element)(prefix)(name of second element) Naming molecular compounds:? Textbook Notes Sunday, September 14, 2008 7:35 PM Chapter 3 Page 1 (prefix)(name of first element)(prefix)(name of second element)? Prefixes eg. Mono, di, tri, tetra? Can leave off mono if it's the first element, also "a" at end of prefix if element start with a vowel? Naming molecular compounds:? Sour taste and can dissolve many metals? Hydro(base of nonmetal + -ic)acid? Binary acids - hydrogen and nonmetal? Oxyanions ending in -ate: (base of oxyanion + -ic)acid? Oxyanions ending in -ite: (base of oxyanion + -ous)acid? Oxyacids - hydrogen and oxyanion? Acids - molecular compounds that release H+ when dissolved in water? Molecular mass, molecular weight? Formula mass - average mass of molecule of a compound? Molar mass - same as molecular except in it is per mol? (Mass of element X in 1 mol of cmpd)/(mass of 1mol of cmpd) x 100%? Can use as a conversion factor and finding empirical formulas? Mass percent composition/mass percent of an element is that element's percentage of the compounds total mass ? Based on the molar mass, we can multiply the empirical formula by how many moles there are in the given sample (given the molar mass of the compound) ? All carbon in sample becomes carbon dioxide, all hydrogen to water? Results weighted and numerical releationships determined? Find how much carbon and hydrogen were in original sample then use subtraction from given mass to get how much oxygen was in the sample then get empirical formula ? Combustion analysis - unknown compound goes through combustion in presence of pure oxygen? Chemical reaction - process in which one or more substances are converted into one or more different ones ? Emit heat, produce carbon dioxide and water? Combustion reaction - substance combines with oxygen to form one or more oxygen-containing compounds ? Chemical equation represents a chemical reaction and must be balanced so that we have the same amount of each type of atom on each side, use coefficients ? Organic compounds come from living things, inorganic came from the earth (eg mined from ground or from ocean) ? Smells such as from perfume are caused by organic compounds? Composed of carbon and hydrogen and a few other elements? Carbon has versatility because of the four possible bonds it can form? Organic compounds easily decomposed and are common in everyday substances? Containing only single bonds = alkanes? Containing double = alkenes? Containing triple = alkynes? 1: meth? 2: eth? 3: prop? 4: but? 5: pent? 6: hex Base numbers? (base name by number of C atoms)(suffix determined by bond number)? Hydrocarbons - organic compounds that contain only carbon and hydrogen, compose common fuels such as oil, gasoline, propane, and natural gas ? Chapter 3 Page 2 5: pent 6: hex? 7: hept? 8: oct? 9: non? 10: dec? 1: -ane? 2: -ene? 3: -yne? Suffix numbers? Table 3.6 pg119? Alcohols, amines, etc.? Table 3.8 pg120? Functional group - characteristic atom or group of atoms (the groups learned in Ch2 of Biol)? Chapter 3 Page 3
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