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