"H-O-H"?! WHAT'S THAT SPELL?!. WATER?. Nomenclature Chapter 5. Chemical Formulas. I. Binary Compounds – *there are two main classes of binary compounds A. Metal + Nonmetal B. Nonmetal + Nonmetal. Section 4.4 – Formulas of Compounds. A. A compound is:
I. Binary Compounds –
*there are two main classes of binary compounds
A. Metal + Nonmetal
B. Nonmetal + Nonmetal
Section 4.4– Formulas of Compounds
A. A compound is:
*the word relative here refers to ratios
The smallest piece of a compound that still has the identity and properties of the compound is known as a _______________________or _______________________.
B. The identity of a compound can be expressed as a chemical formula.
All chemical fomulas tell you:
II. Naming Binary Ionic (metal + nonmetal) Compounds
A. There are two types of binary ionic compounds
1. Type I – metal has fixed charge (representative elements plus Ag+, Zn2+ and Cd2+ )
2. Type II – metal has a charge that may vary (transition, inner transition)
B. Rules for Naming Type I Ionic Compounds
1. The cation (metal) is always named first and the anion is named second.
2. The name of the cation is just the name of that element.
3. The name of the anion takes the root name of the element with an “ide” ending.
IV. Naming Compounds That Contain Polyatomic Ions
A. Polyatomic ions are –
1. Special type: Oxyanions
*see table 5.4
B. Rules for naming compounds with polyatomic anions.
1. Cation comes first, anion second.
2. Polyatomic ion names are not altered with “ide” endings or prefixes.
3. All other rules for naming type I and type II ionic compounds apply.
VI. Naming Acids
An acid is –
A. Binary Acids (H plus one other element)
1. Binary acid names always start with the prefix “hydro”
2. After prefix use anion root name with “ic” ending.
B. Acids Containing Polyatomic Ions
1. NEVER use prefix “hydro”
2. anion may end in “ic” or “ous” (see page 131)
VII. Writing formulas from names.
First, determine whether or not it is ionic, covalent, or an acid.
1. Ionic compounds and acids: Use criss-cross method (works for polyatomic ions too)
2. Covalent Compounds: use prefixes as subscripts in formula.
VIII. Molar Mass
The mass (in grams) of 1 mole of the substance.
IX. Percent Composition of Compounds
Mass Fraction = _________________________________________
Mass Percent of something is the mass of something 1 mole of the compound.
X. Formulas of Compounds
XI. Calculation of Empirical Formulas
1. Obtain the mass of each element present (in grams)
2. Determine the number of moles of each element.
3. Divide the number of moles of each element by the smallest number of moles of the elements present.
4. If needed, multiply the numbers from Step 3 by the smallest integer that will convert them to whole numbers.
Best explained through examples
XII. Calculation of Molecular Formulas
Can be calculated from % Compositions or from Empirical formulas
You need 3 pieces of information:
Empirical formula mass