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 13 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) odide

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

2. Organic Acids 1st word: root formed from anion Suffix ate changed to ic 2nd word: acid C6H5COOH(aq) or HC6H5COO(aq) acetic acid Benzoic acid HCH3COO or CH3COOH

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