Chemical Names Formulas 7 1 Chemical formula indicates

Chemical Names & Formulas 7 -1

Chemical formula… • indicates the relative _____ and ______ of atoms in a compound • Covalent bonding: _______ formula – H 2 O 2 atoms H, 1 atom O • Ionic bonding: _______ (simplest ratio of the cmpd’s pos. & neg. ions) – Mg. Cl 2 1 Mg ion, 2 chloride ions

How many atoms of each element are in Ba 3(PO 4)2 ?

Monatomic ions • ions formed from __________ • page 205 Table 7 -1 (know these…don’t need to memorize, however!)

Naming monatomic ions 1. Cation: simply the name of the element 2. Anion: drop the ending and add –ide • • Na. Cl: sodium chloride Li 2 O: lithium oxide • Na. F ___________ • Al. N ____________

Binary Ionic Compounds • • cmpds composed of 2 different elements Na. Cl • Rules for naming binary ionic cmpds: 1. Write the symbols side by side. . cation first 2. Cross over the charges by using the abs. value of each as the subscript for the other 3. Check…reduce to smallest whole-number ratio, if necessary

Write and name the formulas for the following binary ionic cmpds: • lithium and iodine • sulfur and magnesium • zinc and bromine • fluorine and calcium • sodium and oxygen

Stock Nomenclature • Roman numerals are used to indicate an ion’s charge when it can form more than one ion • copper (I) chloride Cu 1+ • copper (II) chloride Cu+2

Write the formula & name… • copper (I) and oxygen • iron (III) and sulfur • copper (II) and chlorine • tin (IV) and sulfur • vanadium (II) and fluorine • vanadium (III) and bromine

Polyatomic ions • a “charged” group of atoms that are held together by covalent bonds • i. e. SO 42 -

oxyanions • negative ions that contain oxygen • • -ate: most common form of group -ite: one less O than common form hypo: less O than the -ite form per: more O than the -ate form

Examples of oxyanions • Given: Cl. O 31 - is most common form • Cl. O 21_______________ • Cl. O 41________

Write the formula for the following: • copper(II) nitrate • potassium iodide • magnesium hydroxide • ammonium acetate • calcium carbonate • sodium sulfate • iron(III) nitrate

Name the following: • Ca(OH)2 • Fe(OH)2 • Na 2 SO 4 • Cu. SO 4 • Fe. O • Fe 2 O 3

Binary Molecular Compounds • composed of ____ individually bonded (covalent) units • usually cmpds between 2 _______ • 2 systems: – newer: Stock system – older: Prefix system (see p. 212…. know prefixes)

Numerical Prefixes • • • 1 2 3 4 5 6 7 8 9 10

Rules for naming binary molecular cmpds: 1. Write the less electronegative element first. Precede with a prefix only when there are >1 atoms of an element. 2. Write the more electronegative element 2 nd, utilizing the –ide as in binary ionic cmpds. Always precede its name with a prefix. 3. The “o” or “a” of the prefix is usually dropped when the element’s name begins with a vowel. • • IF 3 iodine trifluoride N 2 O 5 dinitrogen pentoxide

Naming acids • Ch 15 – learn about acids • The term acid is used when a specific type of cmpd is in a solution of water …. (aq) means aqueous solution • Common oxyacids to know now: • H 2 SO 4 (aq) sulfuric acid • HNO 3 (aq) nitric acid • H 3 PO 4 (aq) phosphoric acid • H 2 CO 3 (aq) • _____________ • CH 3 COOH (aq) • _____________

Naming acids • -ate ion forms the –ic acid – H 2 SO 4 sulfuric acid – HNO 3 nitric acid – H 3 PO 4 phosphoric acid • -ite ion forms the –ous acid – H 2 SO 3 sulfurous acid – HNO 23 nitrous acid – H 3 PO 3 phosphorous acid

Binary acids… • HCl hydrochloric acid • HF ____________ • HBr ____________ • HI ____________

Sometimes all of the Hs don’t come off of an acid when it reacts……. . • H 2 CO 3 carbonic acid • HCO 31 - hydrogen carbonate

Diatomic elements: • • H 2 N 2 O 2 F 2 Cl 2 Br 2 I 2

Oxidation number • also known as _________ • number assigned to an atom in a molecular cmpd that indicates that general distribution of electrons among the bonded atoms • gives an insight into the combining ability of an atom – not “real” charges but are artificial “bookkeeping” devices to keep track of overall edistribution • Ionic cmpds: the charge on the ion IS the electron distribution ∴ ox. # = charge on ion…physically meaningful info

Summary of Ox # Rules (p. 216) 1. Pure elements have an ox. # of ______ i. e. copper, Cu = ox # = ______ oxygen, O 2 = ox # = ______ 2. More electroneg. element has an ox. # = charge it would have if it were an _____. Less electroneg. element has an ox # = charge it would have if it were a ______. i. e. oxygen in H 2 O O = ox # of ______

3. F: _______ oxidation # 4. O: ____ oxidation # except in peroxide (H 2 O 2) where it is – 1, and with halogens (OF 2) where it is +2. 5. H: ____ except when it’s more ________. than other atoms (metals…. Na. H) where it is ____. 6. Algebraic sum of all ox. #s in cmpd = ____. 7. Algebraic sum of all ox. #s in polyatomic ion = __________. 8. IF ionic, ox. # ______ charge of the ion

Assign oxidation numbers to each element in the following cmpds or ions: • CCl 4 • NO 2 • Li. H • sulfate ion

• nitrate ion • H 3 PO 4 • P 4 O 10

Using the newer Stock system, write formulas for the following molecular cmpds: • nitrogen (II) oxide • phosphorus (III) chloride • sulfur (IV) oxide • bromine

Formula Masses • sum of the average atomic masses of all the atoms represented in a formula • (can be of a molecule, formula unit or ion) • • • Example: Formula mass of H 2 O: 2 (ave. atomic mass of H) + 1(ave. at. mass of O) = 2(1. 01 amu) + 1(16. 00 amu) = 2. 02 amu + 16. 00 amu = 18. 02 amu

Calculate the formula mass of the following: • sulfuric acid • calcium nitrate • phosphate ion • magnesium chloride

Molar Masses • sum of the masses of the elements present in a mole of the molecules or formula units that make up a compound • Molar mass of water, H 2 O: • 1 mole H 2 O = 2 mol H + 1 mol O • 2 mol H x 1. 01 g H = 2. 02 g H 1 mol H • 1 mol O x 16. 00 g = 16. 00 g O 1 mol O + _______ • 18. 02 g • ∴ Molar mass of water = 18. 02 g/mol

What is the molar mass of… • aluminum sulfide • sodium nitrate • barium hydroxide

Using Molar Mass as a conversion factor between “moles” ↔ “mass” • What is the mass, in grams, of 0. 500000 moles of barium hydroxide? • 0. 500000 mol Ba(OH)2 x • = 85. 675 g Ba(OH)2 = 171. 35 g Ba(OH)2 1 mole Ba(OH)2

How many moles are in 6. 60 g of ammonium sulfate?

Remember…. 1 mole = 6. 02 x 1023 “things” • How many molecules are in 50. 0 g of water? • 50. 0 g H 2 O x 1 mol H 2 O x ____g H 2 O __ molecules 1 mol H 2 O • = _________ molecules H 2 O

Percentage Composition • % = part x 100 whole • percentage by mass of each element in a cmpd

Find the % copper in copper(I) sulfide • % Cu = mass of Cu in 1 mole of Cu 2 S x 100% mass of 1 mol of Cu 2 S or… % Cu = mass of Cu in 1 mole of Cu 2 S x 100% molar mass of Cu 2 S • Cu 2 S = _______ g/mol, and in 1 mol Cu 2 S, there are _______ mol Cu = ______ g Cu • % Cu = mass of Cu in 1 mole of Cu 2 S x 100% mass of 1 mol of Cu 2 S • = _____ g Cu x 100% = ____% Cu in Cu 2 S g Cu 2 S

What is the percent carbon in ammonium carbonate?

Empirical formula • formula that shows the smallest wholenumber ______ ratio of the different atoms in a compound • In ionic cmpds, the formula unit usually is the empirical formula

What is the empirical formula of the following molecular formulas? • Ethyne, C 2 H 2 • Benzene, C 6 H 6 • Glucose, C 6 H 12 O 6 • Acetic Acid

Calculation of an empirical formula • Empirical formula: smallest whole-number MOLE ratio of the different atoms in a compound • ∴ • 1)determine moles of each element • 2)determine the simples whole # ratio of these moles

What would the formula be of a cmpd that was composed of 2 mol hydrogen and 1 mol oxygen?

What would the formula be of a cmpd composed of 0. 78 mol Al & 2. 34 mol Br?

What is the empirical formula for a cmpd that contains 0. 900 g calcium and 1. 60 g chlorine?

Determine the empirical formula in a cmpd that is 40. 0% C, 6. 71% H, and 53. 3% O.

If the empirical formula is CH 2 and the molar mass is 42 g/mol, what is the molecular formula?

If the molecular mass for the prev. problem (cmpd that is 40. 0% C, 6. 71% H, and 53. 3% O) is 90 g/mol, determine the molecular formula.

Do Section Review p. 233 1. 2. 3. 4. 5. Na 2 SO 3 Fe 2 S 3 K 2 Cr. O 4 N 2 O 5 N 2 O 4