CHEM 1061 1st Edition Lecture 4 Outline of Last Lecture I 2 7 Introduction to Bonding a Ionic Compounds b Covalent Compounds c Polyatomic Ions II 2 8 Formulas Names and Masses Outline of Current Lecture I Naming a Covalent Compounds b Straight Chain Alkanes II Masses a Mass of Ionic Compounds b Mass of Covalent Compounds III Stoichiometry a Empirical Formula b Mass to Chemical Formula Current Lecture I Naming Covalent Compounds a Normally between two nonmetals b Name the smaller group number first usually written first in the formula c Name the large group number second and add ide ending d Use prefixes to show how many there are Table 2 6 on pg 69 shows the prefixes e EXAMPLE CO2 is Carbon Dioxide f If they are in the same group name the one in the LARGER period first These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II III IV V VI g EXAMPLE S02 is Sulfur dioxide h An exception to these rules is that the halogens are named before oxygen i EXAMPLE Cl2 O7 is dichlorine heptaoxide Straight Chain Alkanes a Alkanes contain Carbon and Hydrogen b The name depends on the number of Carbon c Prefixes are found on table 2 7 d Example 1 Carbon meth 2 Carbons Eth Masses a To find the atomic mass of elements look on the periodic table b Units i Atomic Mass Units amu ii Daltons Da iii EXAMPLE Atomic mass of Sodium Na atomic mass of one sodium atom 22 99 amu c Mass of Ionic Compounds i Called a formula mass ii Add up the atomic masses and how many of each iii EXAMPLE Ba NO3 2 261 32 amu d Mass of Covalent Compounds i Called molecular mass ii Add up the atomic masses and numbers of each iii EXAMPLE ethane C2H6 30 068 amu CHAPTER THREE Stoichiometry of formulas and equations a Stoichiometry elemental part measure b Used to find measurements from balanced equations c Mole abbr mol SI unit for amount of a substance d Avogadro s Number 6 022 x 10 23 entities 1 mole entities e Mass amu of 1 atom is the same numerically as the mass in grams of 1 mol of the atom f Ex 1 Carbon atom 1 amu 1 mol C atoms 12 g 6 022 x 10 23 C atoms g Ex 1 molecular H20 18 amu 1 mol H2O 18g 6 022 x 10 23 Molecules H2O h SAMPLE PROBLEM How many mole of NaCl are in 98 4g of NaCl How many Sodium Na are there 98 4g NaCl x 1 mol NaCl 58 5g NaCl 1 68 mol NaCl 1 68 mol NaCl x 1 mol Na 1 mol NaCL x 6 022 x 10 23 Na ions 1 mol Na 1 01 x 10 24 Na ions Empirical and Molecular Formula a Percent by mass of elements in a formula Mass Percentage to Chemical Formula a Compound is 40 C 6 73 H and 53 3 O By mass b Determine Empirical Formula Smallest whole number ratio between the elements c Steps i Choose Sample Mass Mass 100g therefore C 40g H 6 73g and O 53 3g
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