Chemical Compounds Honors Chemistry

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

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

% Composition = (part/whole) x 100 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

molar mass of anhydrate + x(molar mass of water) Percent Composition of Hydrate Definition: 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

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

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

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+

NaCl Fe2S3 iron(II) sulfide 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

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

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

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

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

1 extra oxygen ClO4-1 perchlorate ClO3-1 chlorate 1 less oxygen Anion Description Example 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

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

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

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

More Practice dihydrogen monoxide nitrogen tetrabromide S2O6 H2O NBr4 disulfur hexoxide

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

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

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

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

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

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

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

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

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

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 ?

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) # C atoms Stem 1 meth 9 non 2 eth 10 dec 3 prop 11 undec 4 but 12 dodec 5 pent 13 tridec 6 hex 14 tetradec 7 hept 15 pentadec 8 oct 16 hexadec

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

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

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-.

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

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.

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

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

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

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

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

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

Physical Properties of Structural Isomers Melting Point (°C) Boiling Point (°C) Density at 20°C Butane -138.4 -0.5 0.5788 Methylpropane -159.4 -11.633 0.549

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

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

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)

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