chapter 3 chemical compounds. compounds combination of two or more elements molecular formulas for...

Chapter 3

Chemical Compounds

Compounds combination of two or more elements

• molecular formulas for molecular compounds

• empirical formulas for ionic compounds

K2Cr2O7

Naming Binary Molecular Compounds

Usually more metallic nonmetal first then change ending of second to –ide

Use Greek prefixes for number, omit mono- for first nonmetal

1. Mono-

2. Di-

3. Tri-

4. Tetra-

5. Penta-

6. Hexa-

7. Hepta-

Binary Molecular Compounds

H2O water

NH3 ammonia

H2S hydrogen sulfide

CO carbon monoxide

CS2 carbon disulfide

N2O4 dinitrogen tetroxide

CCl4 carbon tetrachloride

Which of the following compounds is NOT named correctly?

NO2nitr

ogen d

ioxid

e

S2Cl2

disulfu

r dich

l...

OF2oxy

gen d

ifluor

ide

ClFch

lorin

e flu

oride

SiCl4

silic

on te

trach

...

7%2% 0%

91%

0%

1. NO2 nitrogen dioxide

2. S2Cl2 disulfur dichloride

3. OF2 oxygen difluoride

4. ClF chlorine fluoride

5. SiCl4 silicon tetrachloride

Organic Compounds - Ethanol

Condensed formula Molecular formula CH3CH2OH C2H6O

Hydrocarbons

• alkanes – CnH2n+2

– octane

• alkenes – CnH2n

– Ethylene

• alkynes – CnH2n-2

– acetylene

C=C

H

H H

H

H―C≡C―H

Alkanes – CnH2n+2

• methane – CH4

• ethane – C2H6

• propane – C3H8

• butanes – C4H10

• pentanes – C5H12

• hexanes – C6H14

• heptanes – C7H16

• octanes – C8H18

• nonanes – C9H20

• decanes – C10H22

Butane

• Butane molecules are present in the liquid and gaseous states in the lighter

Alcohols

• Replace ―H with ―OH

Alkanes and their Alcohols

Straight & Branch-Chain Alkanes

Some Common

Alkyl Groups

Alkane Isomers

Naming Branch-Chain Alkanes

• select the longest chain alkane as the base name

• determine the side chains and give them a number corresponding to the carbon number on the base chain

• use Greek prefixes of mono-(1), bi-(2), tri(3), etc. for multiplicity of same side chain

Naming Branch-Chain Alkanes

2,2,4-trimethylpentaneor iso-octane

The correct name for this compound is?

CH3―CH2―CH―CH2―CH3

C2H5

3-e

thyl

propa

ne

3-m

ethyl

penta

ne

3-e

thyl

penta

ne

hepta

ne

2-e

thyl

penta

ne

9%

43%

3%3%

41%

1. 3-ethylpropane

2. 3-methylpentane

3. 3-ethylpentane

4. heptane

5. 2-ethylpentane

Cyclic hydrocarbons

IonicCompounds

Characteristics of compounds with ionic bonding:

• non-volatile, thus high melting points

• solids do not conduct electricity, but melts (liquid state) do

• many, but not all, are water soluble

Formation of Ionic Compound, NaCl

Valance, Charge on Ions

• compounds have electrical neutrality

• metals form positive monatomic ions

• non-metals form negative monatomic ions

• balance charges

• Al3+ O2-

Al2O3

Valence of Metal Ions

Monatomic Ions

Group IA +1

Group IIA +2

Maximum positive valence

equals

Group A #

Valence of Non-Metal Ions

Monatomic Ions

Group VIA -2

Group VIIA -1

Maximum negative valence

equals

(8 – Group A #)

Charges on Some Common Monatomic Cations and Anions

Common metals with only one ion

• Al3+

• Zn2+

• Ag+

Polyatomic Ions

-ate and -ite

• NO3- nitrate

• NO2- nitrite

• -ate is great, -ite is slight-ate has one more oxygen than –ite

• hypo- under one less

• per- completely one more

Name other ions by analogy with element above

• SeO42- selenate

• BrO3- bromate

• HSe- hydrogen selenide

• H2AsO4- dihydrogen arsenate

Permanganate is?

MnO2-

MgO4-

MnO42

-

MnO4-

MnO4-

0% 0% 0%0%0%

1. MnO2-

2. MgO4-

3. MnO42-

4. MnO4-

5. MnO4-

IO- is?

hypoio

dite

iodite

iodid

e

iodat

e

iodin

e m

onoxi

de

0% 0% 0%0%0%

1. hypoiodite

2. iodite

3. iodide

4. iodate

5. iodine monoxide