Ch. 8.2 Molecular Compounds

Topic	Ch. 8.2 Molecular Compounds		Name

Essential Question	Why are there so many types of molecular compounds?		Class	Chemistry - 4th block
			Date

Questions		Notes
Write down questions that occur while you work.		Properties of molecular compounds vary widely some are hard & brittle, others are ____________, __________, ____________ at room temp can be _____________, _____________, _____________ boiling points vary from __________ to over __________ most are ___________________. When dissolved in solvent, they do not typically conduct ________________. The properties of molecular substances depend on structure of the individual molecule, including the types of covalent bonds formed within the molecule the attractions between molecules Example: water H2O smallest piece of water = _____________________________ we think of water as a __________, or a __________, or an ___________ 1 cup of water = _________________________________ (8 x 1024) water moleculesl water molecules bounce off of each other, are constantly in motion, form no particular crystalline organization (_________) ice (_________) is water formed as an organized crystal structure, is hard and brittle like an __________ compound The great variety of structures possible with molecular substances is what gives them their great variation in properties. Molecules can be classified into categories small constructured from about __________ atoms or less, though there is no specific number that categories a molecule as small tendencies of substances made from small molecules almost always __________ or ___________ at room temp include some of the most important molecules related to the functioning of our entire _____________________ often ______________________, such as acetaminophen, which is liquid in its pure form Example: water single polar water molecule = 3 atoms essential for life solid form is less dense than liquid form (else when frozen bodies of water would kill all higher life forms, preventing the evolution of all but the simplest creatures Example: carbon dixode & oxygen medium typically formed from more atoms than small molecules, but not much more than _________ atoms tendencies of substances made from medium molecules ___________ or _________________ at room temperature lipids: __________ or _________________, molecules primarily made from carbon & hydrogen may include small numbers of other elements depending on the _________ & ________ of a fat molecule, the substance might be liquid or solid at room temp Example: vegetable oil or butter typically ____________ & ____________ in water steroids have larger percentage of atoms that are ______ hydrogen or carbon have _____ rings of carbon atoms can function as hormones, drugs, vitamins or poisons anabolic steroids, used as performance-enhancing drugs, all mimic the shape of __________________, a natural steroid. long-chain hydrocarbons molecules formed purely from long chains of _____________ & ___________ atoms similar to fats except they lack the ___________ atom that are part of fatty acids produced in living organisms medium sized HC tend to form ___________________ like petroleum jelly larger medium-sized HC tend to form harder substances like wax large polymers: made from many _____________ molecules monomers: smaller molecules that ___________ bond together to make polymers all plastics are various kinds of polymers recycling numbers on bottles & packages tells which kind of polymer (plastic) the object is made from 1 2 3 4 5 6 7 synthetic polymers: plastics are typically made in labs & factories natural polymers:__________ & _____________ are made from the simple sugar glucose, bonded slightly differently to produce different materials starch is digestible cellulose is not digestible homopolymer: polymers from from only ____ type of monomer Ex. starch & cellulose from glucose copolymer: polymers from ___________ types of monomers Ex. DNA constructed from 4 different monomers DNA provides the code necessary to build proteins, by adding 1 monomer (amino acid) at a time. Ex. proteins constructed from up to 20 different monomers (called amino acids) The order of amino acids inthe protein polymer is based on the order of the monomers (bases) in the DNA. network covalent substances: molecules where large numbers of atoms are _____________ bonded in an ___________________ manner Example: sand sand grains are actually made from a single individual molecule, usually quartz, which is Si & O. Since every atom in quartz is covalently bonded, the entire grain can be considered a molecule. Example: carbon Carbon is special because it can form many diff. kinds of network covalent substances diamond, graphite: buckyballs: nanotubes: Chemical Formulas of Covalent Compounds In molecular substances there is a _______________________ that is _the_ single molecule of that substance. Network covalent substances are treated more like ________ substances where the ratio of elements is used because the large number of covalently bonded atoms forms a single unit, just like in ______ in ionic substances. empirical formula: a formula that describes the simplest _________ of elements in a substance molecular formula: a formula that indicates the exact type & number of each ________ in a single molecule of a substance elements are ordered ____________________, unlike ionic compounds where the _______________ atom is listed 1st Sometimes the empirical formula = molecular formula (H2O), sometimes not (benzene empirical = CH, molecular C6H6) Examples C2H2 NH3 C2H5O Naming Simple Binary Molecular Compounds Molecular substances vary so much in their basic structures that different naming systems are used depending on the molecule organic molecules: made primarily from carbon, hydrogen, oxygen & the halides have a complex naming system dedicted to this class the system write the name of the compound like it’s a simple ionic compound P2S3 = _______________________________ H2O = _______________________________ CO = _______________________________ add prefixes to each name to tell how many of that atom are in the molecule; if there is only ____ atom of the 1st element, omit the mono prefix P2S3 = _______________________________ H2O = _______________________________ CO = _______________________________













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