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Chemical Compounds

Chemical Compounds. Honors Chemistry. 3 Types of Formulas. Empirical : Smallest whole-number-ratio of atoms or ions in a compound Ex. CH 2 NH 3 Molecular : Tells you the actual number of atoms of an element in a compound Ex. C 2 H 4 N 2 H 6

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Chemical Compounds

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  1. Chemical Compounds Honors Chemistry

  2. 3 Types of Formulas • Empirical: Smallest whole-number-ratio of atoms or ions in a compound • Ex. CH2 NH3 • Molecular: Tells you the actual number of atoms of an element in a compound • Ex. C2H4 N2H6 • Structural: Indicates how the atoms are bonded to each other

  3. How does the mole relate to compounds? REMEMBER Atoms are too small to count or mass individually. It is easier to count many or mass many. amu gram (atomic scale) (macroscopic scale) mole atoms, ions, molecules, or formula units Molar Mass= mass, in grams, per 1 mole of a substance units = grams/mole (g/mol) • Example: the molar mass of H2O is 18.0 g/mol

  4. Molecular formulas and molar masses are used to determine Percent Composition • Definition: percentage, by mass, of each element in a compound % Composition = (part/whole) x 100 • Problems • Calculate the % composition of NaCl % Na: % Cl: 39.3% Na 60.7% Cl

  5. Percent Composition of HydrateDefinition: A hydrate is an ionic compound with water embedded in it. • Calculate the % water in a hydrate, Mg3(PO4)2. 6H2O. molar mass of hydrate = molar mass of anhydrate + x(molar mass of water) % water = 370.9 g/mol Mg3(PO4)2 . 6H2O 29.1% H2O

  6. How can you identify different types of compounds? • Type of Compound Identification • Ionic Begins with a metal • Covalent Begins with a nonmetal • Acid Begins with a hydrogen and is aqueous • Hydrate Ionic Compound and Water

  7. Ionic Compounds • Made from a positively and negatively charged ion • Overall charge of the compound is zero • Types of Ionic Compounds • Binary • Ternary

  8. Binary Compounds: Composed of two monatomic ions • Primary Rules for Charges: YOU MUST KNOW THESE RULES 1 or IA +1 2 or IIA +2 3 or IIIA +3 15 or VA -3 in binary compounds with metals, H, or NH4+ 16 or VIA -2 in binary compounds with metals, H, or NH4+ 17 or VIIA -1 in binary compounds with metals, H, or NH4+

  9. Ionic Compounds – look at charges; roman numerals needed for elements with more than one charge (polyvalent) a. Binary Compounds – only monatomic ions in compound sodium chloride iron(III) sulfide FeS NaCl Fe2S3 iron(II) sulfide

  10. Ionic Compounds Binary Compounds HF(g) AlCl3 Cr2O3 hydrogen fluoride aluminum chloride chromium(III) oxide

  11. Ionic Compounds Ternary Compounds– contain 1/more polyatomic ions in compound sodium carbonate chromium(III) oxalate ammonium sulfate Na2CO3 Cr2(C2O4)3 (NH4)2SO4

  12. Ionic Compounds • Ternary Co3(AsO4)2 CuSO3 Note for polyatomic ions: -ate vs. –ite per- and hypo- cobalt(II) arsenate copper(II) sulfite

  13. Ionic Compounds • magnesium hydroxide • calcium sulfate • ammonium phosphate Mg(OH)2 CaSO4 (NH4)3PO4

  14. 1 extra oxygen ClO4-1 perchlorate per_____ ate ClO3-1 chlorate the most common form _______ate 1 less oxygen ClO2-1 chlorite _______ ite 2 less oxygens ClO-1 hypochlorite hypo_____ ite

  15. Now try these… • sulfite • periodate • phosphite • bisulfite SO3-2 IO4-1 PO3-3 HSO3-1

  16. Check for Understanding MgH2 • magnesium hydride • calcium acetate • FeS2O3 • SnI4 Ca(CH3COO)2 iron (II) thiosulfate tin (IV) iodide

  17. Molecular Compounds– formed between 2 nonmetals *Use prefixes mono = 1 hexa = 6 di = 2 hepta = 7 tri = 3 octa = 8 tetra = 4 nona = 9 penta = 5 deca = 10 Binary Compounds: only 2 elements in the compound; use prefixes and –ide ending CCl4 N2O5 carbon tetrachloride dinitrogen pentoxide

  18. More Practice • dihydrogen monoxide • nitrogen tetrabromide • S2O6 H2O NBr4 disulfur hexoxide

  19. Hydrates– ionic compound with water bonded in its structure anhydrate . xH2O • anhydrate  ionic compound • add prefix to indicate # of water molecules CuSO4.5H2O copper(II) sulfate pentahydrate

  20. Acids – compounds that produce hydrogen ions in water • Mineral Acids • Binary Acids 1st word: prefix = hydro root formed from anion suffix –ide changed to -ic 2nd word: acid HCl(aq) HBr(aq) hydrochloric acid hydrobromic acid

  21. B. Oxyacids • 1st word: root from anion Suffix ate changed to ic Suffix ite changed to ous **Exceptions: if you have sulf or phos as roots, change the root to sulfur or phosphor • 2nd word: acid HNO3 HNO2 phosphorous acid Nitric acid Nitrous acid H3PO3

  22. Common Acids to Know hydrochloric acid • HCl • H2CO3 • HClO4 • H2SO4 • H3PO4 • HNO3 • CH3COOH = HC2H3O2 carbonic acid perchloric acid sulfuric acid phosphoric acid nitric acid acetic acid

  23. Salts • Ionic compound composed of a cation (positive ion) and an anion (negative ion) from an acid • NaCl • CaSO4 • NaHCO3 • NaHSO3

  24. Organic Compounds • >11 million compounds • Contain a C-C or C-H bond in combination with N, O, S, P or halogens • Simplest = CH4 • Most complex = DNA

  25. Hydrocarbons • Only have carbon and hydrogen • Simplest organic compounds • From petroleum (crude oil)

  26. Organic Compounds Allotropes of carbon Allotropes: Different forms of an element in same physical state Catenation: ability of an element to form chains and/or rings of covalently bonded atoms

  27. Structural Formula • Indicates the number and types of atoms present in a molecule and also shows the bonding arrangement of the atoms • One possible isomer of C4H10 • Does not show 3D shape

  28. Naming Organic Compounds • Alkanes – saturated organic compound • Contains only single bonds • General Formula: CnH2n+2 • Alkenes – unsaturated organic compound • Contains at least one double bond • General Formula: CnH2n • Alkynes – unsaturated organic compound • Contains at least one triple bond • General Formula: CnH2n-2 • What type of organic compound is C4H10 ?

  29. Naming Hydrocarbons • Find the longest chain of carbon atoms. Choose the base name that describes the number of carbon atoms in this chain. Use the following endings: Alkane (ane), Alkene (ene), Alkyne (yne)

  30. Naming hydrocarbons • Number the carbon atoms in this longest chain beginning at the end nearest the 1st branching. • If there is branching at equal distances from both ends of the longest chain, begin numbering at the end nearest the branch that is 1st in alphabetical order. 1 2 3 4

  31. Naming Alkenes and Alkynes • Number the carbon atoms in the chain sequentially, beginning at the end nearer the double or triple bond. If the parent chain has more than 3 carbons, insert the number describing the position of the double or triple bond (indicated by its 1st carbon location) before the base name. 1-butene 2-butene

  32. Branches/Substituents on the Main Chain • Additional Hydrocarbon branches The hydrocarbon branches are called alkyl groups: -CH3 methyl -CH2CH2CH3 propyl -CH2CH3 ethyl -CH2CH2CH2CH3 butyl 2)The organic halides are elements from group 17 in the periodic table. The prefix can be fluoro-, chloro-, bromo- or iodo-.

  33. Hydrocarbon Branches or Substituents Assign the name (stem with yl ending) & position number to each substituent or branch. Arrange substituentsin alphabetical order. The hydrocarbon branches are called alkyl groups: -CH3 methyl -CH2CH2CH3 propyl -CH2CH3 ethyl -CH2CH2CH2CH3 butyl

  34. Naming hydrocarbons • Use the appropriate prefix to group like substituents: di = 2, tri = 3, tetra = 4, etc. Do not use these prefixes when alphabetizing attached groups • Write the name as a single word. Use hyphens to separate numbers & letters and commas to separate numbers. Do not leave any spaces.

  35. Naming Alkenes and Alkynes In naming alkenes and alkynes, the mulitple bond takes positional precedence over substituents on the carbon chain. The double bond is assigned the lowest possible number. 3,3-dimethyl-1-butene 4-methyl-2-pentene

  36. Naming Organic Halides (Alkyl Halides) • The organic halides are named as halo- derivatives of the parent hydrocarbon. The prefix can be fluoro-, chloro-, bromo- or iodo-. 1-chloropropane 1-chloro-2-methylpropane

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  38. Alkene Examples 3,4-dimethyl-3-hexene 3-ethyl-4,6-dimethyl-1-heptene

  39. Naming Alkynes • Named just like the alkenes except the suffix –yne is added ethyne 1-butyne propyne 2-butyne

  40. Alkyne Examples 3-methyl-1-butyne 5-methyl-2-hexyne

  41. Arrangement of Atoms • Isomers – compounds that have the same molecular formula but different structures • More C atoms in formula, more isomers • 18 isomers for C8H18 • 35 isomers for C9H20 • 75 isomers for C10H22 Isomers of C6H14

  42. Structural Isomers • Isomers in which the atoms are bonded together in different orders. • C4H10 (note continuous chain of C atoms) butanemethylpropane

  43. Physical Properties of Structural Isomers

  44. Ex #1) Butane, C4H10 Ex #2) Butene, C4H8 Ex #3) 2-Butene, C4H8 Ex #4) methyl propene, C4H8 ISOMERS

  45. Functional Groupsan atom or group of atoms that is responsible for the specific properties of an organic compound

  46. Diffusion and Effusion Diffusion: the mixing of molecules of 2 or more gases due to their molecular motion (spontaneous) Effusion is the movement of gas atoms or molecules through a small opening. Gases confined in a container randomly pass through a tiny opening in the container. ex) hole in a tire; soda bottle (CO2 escaping)

  47. Graham’s Law: The rate of effusion of a gas is inversely proportional to the square root of its molar mass. He and SF6 demo

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