CHEMICAL NOMENCLATURECHAPTERS 8-9

Chemistry

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BEGINNING OF CLASS 2/28/13

1. Get out paper to begin notes for Nomenclature.

2. Label your notes ‘Chemical Formulas’

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CHEMICAL FORMULAS4 naming systems:1. Naming Acids -H is first element (except water)2. Naming Organic Compounds -starts with C, contains a few H’s, and maybe a few O’s3. Naming Binary Ionic Compounds -starts with a metal4. Naming Binary Molecular Compounds -starts with a nonmetal other than H or C

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ESSENTIAL PATTERNS

You must memorize the polyatomic ions!!polyatomic ion: groups of atoms that behave as a unit and possess an overall charge. -if more than one polyatomic is needed, place a parenthesis around it before adding the subscriptPattern 1:The –ate form of polyatomics have 1 more O than the –ite form, but the charge does not change.~prefix hypo- means 1 less O than the –ite form.~prefix per- means 1 more O than the –ate.

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ESSENTIAL PATTERNS

Pattern 2:The –ates with charges of -2 & -3, can have a H added to form new polyatomic ions.~H + CO3

-2 becomes HCO3-1 (hydrogen carbonate)

~H + PO4-3 becomes HPO4

-2 (hydrogen phosphate)

~H + HPO4-2 becomes H2PO4

-1 (dihydrogen phosphate)

If you keep adding H’s until it becomes neutral, you’ve made an acid!

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ESSENTIAL PATTERNS

Pattern 3:Remember your periodic trend for oxidation numbers.~group 1 metals have a +1 charge~group 2 metals have a +2 charge~group 17 nonmetals have a -1 charge~group 16 nonmetals have a -2 charge~group 15 nonmetals have a -3 charge~group 3-15 metals have varying oxidation states, except

Ag+1, Zn+2 and Al+3 (know these!!)

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NAMING ACIDS

(We will talk more about acids in Ch 19)There are two types of acids:1. binary acid: contains hydrogen and one other element -when naming use the prefix hydro- plus the

root of the second element with the suffix –ic, followed

by the word acid. -ex: HCl

H = hydro- Cl = chloride = chloric hydrochloric acid

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Some acids are not binary, but are named according to the binary acid rules when oxygen is not present, as in HCN.

H = hydro CN = cyanide = cyanic

hydrocyanic acid2. oxyacid: an acid that contains an oxyanion

(oxygen containing polyatomic ion) -the name depends on the oxyanion present

-the name consists of the root of the anion, a suffix,

and the word acid ♦if the anion suffix is –ate, it is replaced with -

ic ♦if the anion suffix is –ite, it is replaced with -

ous

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-examples: ~HNO3

NO3 = nitrate

= nitric nitric acid ~HNO2

NO2 = nitrite

= nitrous nitrous acid

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When writing formulas from the name, the number of H’s depends on the charge of the

anion.

HNO3 has 1 H because the nitrate ion has a -1

charge.

HCl has 1 H because the chloride ion has a -1 charge.

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BEGINNING OF CLASS 3/4/13

1. Get out Nomenclature notes.2. Find the last notes taken (on oxyacids).3. Get ready to do practice naming acids, so

look over your rules.

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NAMING ACIDS PRACTICEName the following acids:1.HBr2.H3PO4

3.H2SO4

4.H2SO3

Write formulas for:5. iodic acid6.hydrophosphoric acid

More Practice: p 250 # 18-22, 28b12

NAMING ORGANIC MOLECULES

organic compound: compound that contains C, H and sometimes an O. hydrocarbons -only contain C and H -simplest of the organic compounds -covalent moleculesclassified as: alkanes, alkenes, alkynes,

aromatics

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ALKANES

alkane: hydrocarbon containing only C-C single bonds (-ane ending)

-saturated hydrocarbon: each carbon contains a maximum of 4 single covalent bonds with other atoms -can be shown as straight chains, branched chains, or cyclic chains -follows the formula:

CnH2n+2

example: if n = 1, then C1H2(1)+2

to give CH4 14

UNBRANCHED (STRAIGHT CHAIN) ALKANES

C-C bonds form in a straight line.

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NAMING UNBRANCHED ALKANES1. Use a prefix for the number of carbons it contains: meth- 1 C hex- 6 C eth- 2 C hept- 7 C prop-3 C oct- 8 C but- 4 C non- 9 C pent-5 C dec- 10 C2. Follow the prefix with the ending, -ane

Example: C8H18 is named octane

Hint: Hydrogen has nothing to do with the actual naming of the compound, except to help you determine if the C-C bonds are single or multiple

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BRANCHED ALKANESDerived from a straight-chain alkane by

replacing one or more of the H atoms atoms with alkyl groups, groups substitued for one or more H’s 1. a suffix that identifies the parent straight-chain alkane ♦count the number of C atoms in the longest continuous chain2. a prefix that identifies the branching alkyl group 3. the number of the carbon atom to which it is attached

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NAMING BRANCHED ALKANES EXAMPLE

1. propane is the parent chain2. contains two methyl groups

♦when more than one branch of the same kind is shown, use the Greek prefixes (mono-, di-, tri- etc.)

3. Both substituted groups are on the same C, C#2

Put it together: 2,2-dimethylpropane

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NAMING BRANCHED ALKANES PRACTICE

1. CH3 CH3

CH3CHCH2CHCH2CH3

2. CH3

CH2 CH3 CH3

CH3CHCH2CH2CHCH2CHCH3

3. Draw 3,4,5-triethyloctane4. Draw 2,3,dimethyl-5propyldecane

More practice p 705 # 3-4

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CYCLIC ALKANES

cycloalkane: alkanes where the carbon atoms are arranged in a ring (cyclic) structure

-contain minimum of 3 carbons

Use the same rules for naming straight-chain alkanes, but with a few modifications:

-the ring is the always the parent chain

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NAMING CYCLIC ALKANES

1. Count the number of carbons and name as

a straight-chain alkane 2. Once named, place the prefix, cyclo- in

front

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NAMING CYCLIC ALKANESCyclic alkanes, like branched alkanes, can contain

substituent groups, with each group attached being numbered with the lowest possible set of numbers

♦ if there is only one substituted group, you do not

need to number it

http://en.wikibooks.org/wiki/Image:Substituted_cyclohexane_samples1.png

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NAMING CYCLOALKANES

Complete practice problems #10-11 on p 708

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PROPERTIES OF ALKANES

1. longer chains generally = higher mp/bp

2. relative unreactive3. nonpolar

4. immiscible in water

5. readily combust in oxygen

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ALKENES

unsaturated hydrocarbon: contains one or more double or triple bonds between C atoms

-does not have a maximum number of H alkene: has at least one double bond between

carbon atoms -minimum of 2 C’s -alkenes with one double bond have twice as

many hydrogens as carbons, as shown in the

formulaCnH2n

-look at Table 22-4 on page 711

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NAMING ALKENESAlkenes are named in much the same way as

alkanes, except we change the –ane ending to –ene

-examples: ethane becomes etheneH2C=CH2

propane becomes propeneH2C=CH-CH3

-if there are 4 or more C’s, you must state the location of the double bond using the

lowest number possible

C=C-C-C is 1-butene (not 3-butene)C-C=C-C is 2-butene

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NAMING CYCLIC ALKENESWhen you name cyclic alkenes, carbon number 1 must be attached to the double bond -example: cyclopentene (not 1-cyclopentene, since the 1 is assumed)

-example: 1,3-dimethylcyclopentene

What if the alkene is branched?

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NAMING BRANCHED ALKENES

You name branched alkenes like branched alkanes with 2 differences:

-parent chain is always the longest chain that includes the double bond, -the position of the double bond, not the

branches, determines how the parent chain is numbered

CH3

Example: CH2=C-CH2-CH3

2-methylbutene Lets look at the example on p 713

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NAMING ALKENES PRACTICE

P 714 # 18P 716 # 21 b & d

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MORE ALKANE & ALKENE PRACTICE

P 732-733 # 61-65, 66ab, 67

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PROPERTIES & USES OF ALKENES

Properties1. nonpolar2. relatively low mp/bp3. fairly reactive (electron density around double

bond)

Uses1. Making plastic bags/jugs (polyethylene)2. Ripening fruit (ethylene, or ethene-fat soluble

hormone)3. Making rubber (different alkenes)4. aromatics/scents

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ALKYNES

alkyne: contains one or more C-C triple bonds -must have at least 2 carbons -are named using the same rules as naming

alkenes, except with the ending –yne instead of –ene

Properties of AlkynesSimilar chemical and physical properties as

alkenes, though tend to be more reactive because of the high area of electron density on the triple bond

-will burn at temp >3000oC when in O2

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Uses of Alkynes1. Acetylene (ethyne) torches in welding2. As a reagent in the manufacture of plastics

and other organic industrial chemicals

PracticeP 716 # 21a, p 733 # 66c

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FUNCTIONAL GROUPSCabron can also bond with atoms other than hydrogen or

other carbon compounds -the most common are: O, N, F, Cl, Br, I, S and P

functional group: an atom or group of atoms that reacts in a certain way in an organic molecule.

•the addition of a functional group produces a compound

with different physical and chemical properties than the

parent hydrocarbon.

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Important functional groups:1. alcohol, -OH -since it is attached to a C, it is NOT a hydroxyl group (hydroxide)2. phosphate, -PO4

3. sulfhydryl, -SH

*functional groups change the shape of a hydrocarbon molecule

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NAMING IONIC COMPOUNDS

formula unit: simplest ratio of ions represented in an ionic compound

-remember that ionic compounds form a crystal lattice, consisting of many cations and anions.

-the overall charge for the compound is 0

Most ionic compounds are binary, consisting of two monatomic ions.

-monatomic ion: one atom ion, either positively (cation) or negatively (anion) charged

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Remember that we determine the charge of each ion by its oxidation number.

Formula Rules for Ionic Compounds1. write the cation first, followed by the anion 2. state the charges of both ions3. cross the number for the charge of one ion to become the subscript for the other ion. -subscripts are used to state the number of

each atom in the compound

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Example: Determine the formula for the ionic compound formed when potassium reacts with oxygen.

1. Cation = potassium = K Anion = oxygen = O2. K+1 O-2

3. K+1 O-2

K2O1

K2O

You try: Determine the formula for the ionic compound formed when aluminum reacts with chlorine.

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IONIC BONDING PRACTICE 1Write the correct formula for the following pairs of

atoms:1. potassium and iodine

2. magnesium and chloride

3. aluminum and bromide

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NAMING IONIC COMPOUNDS

1. cation appears first in the name.2. anion follows, changing its ending to –ide for

single atom ions.

Ex: What is the name of MgCl2?

magnesium chloride

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IONIC COMPOUNDS PRACTICE 2

Write the formula and the name.

1. Na2S

2. Ga2S3

3. CaSe

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IONIC COMPOUNDS WITH POLYATOMIC IONS

Use the same rules as binary ionic compounds. -the cation comes first, followed by the anion -state the charges -cross over the number for the chargesRemember: -if you have more than one polyatomic ion,

place parenthesis around the polyatomic ion, with

the subscript outside the parenthesis.

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Example: Determine the formula for the ionic compound formed when beryllium reacts with cyanide.

1. Cation = beryllium = Be Anion = cyanide = CN-

2. Be+2 CN-1

3. Be+2 CN-1

Be1(CN)2

Be(CN)2

You try: Determine the formula for the ionic compound formed when ammonium reacts with iodine.

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IONIC BONDING PRACTICE 3Write the correct formula for the following pairs of

atoms:1. ammonium and oxygen

2. lithium and nitrate

3. aluminum and hydroxide

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NAMING WITH POLYATOMIC IONS

Use the binary ionic rules, however: -do not change the ending of the polyatomic

ions, even when they are the second atom.Example: Al2(SO4)3

aluminum sulfate

Rule: You must state the charge of all metals not

included in groups 1 and 2 because many have

multiple charges (except our exceptions)

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RULES FOR TRANSITION METALS

*According to the previous rules, FeO and Fe2O3 would both be named iron oxide,even though they are not the same compound*

Since many transition metals can have more than one charge, the name must show this. This is done using roman numerals. -FeO is named iron (II) oxide because Fe has a

+2 charge -Fe2O3 is named iron (III) oxide because Fe has a

+3 charge*The roman numeral states the charge of the metal*46

Q: How do I know the iron in FeO has a +2 charge? A: The oxide ion has a –2 charge, so the Fe must have a +2 charge so the compound is overall neutral.

Q: How do I know the iron in Fe2O3 has a +3 charge?

A: There are three oxide ions with a –2 charge:(3 ions)(-2 charge/ion) = a total of –6 charge

Since the overall charge must be neutral, the iron must have a total charge of +6. Therefore:

(2 ions)(x charge/ion) = +6 x = +3

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IONIC COMPOUNDS PRACTICE 4

Write the formula given & the name of each compound.1. FeCl32. Zn3P2

3. CuS4. AuF5. CuC2H3O2

6. AgHCO3

7. ZnSO4

8. Pb(CO3)2

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NAMING MOLECULES

1. The first element in the formula is named first, using the entire element name.

2. The second element in the formula is named using

the root of the element and adding the suffix –ide.

3. Prefixes are used to indicate the number of atoms of

each type that are present in the compound. -exception: 1st element never uses the prefix

mono- -drop the final letter of the prefix if element

name begins with a vowel.

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Prefixes you need to know:# atoms prefix

1 mono- 2 di-

3 tri- 4 tetra-

5 penta- 6 hexa-

7 hepta- 8 octa- 9 nona- 10 deca- 50

NAMING BINARY MOLECULES-EXAMPLE

Name the compound P2O5, which is used as a drying and dehydrating agent.

1st atom: P = phosphorus 2nd atom: O = oxygen = oxide

There are 2 phosphorus = diphosphorusThere are 5 oxygens = pentoxide (drop the –a of penta-)

Put it together: diphosphorus pentoxide

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NAMING BINARY MOLECULES PRACTICE

Name the following molecules:1. CCl4

2. As2O3

3. CO

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WRITING MOLECULAR FORMULAS

Use the prefixes in the molecule’s name to determine the subscript for each atom in the compound.

- phosphorus tribromide P Br

1 (no prefix) 3 (tri) PBr3

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WRITING FORMULAS PRACTICE

1. oxygen difluoride

2. dinitrogen tetrasulfide

3. phosphorus pentachloride

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