9/18/2009 1 Chem 105X Wed. Sept. 18, 2009 Today Tutors Laboratory 1)Ionic and Covalent compounds 2)Formulas and names 3)Mixed nomenclature 4)Calculations: a. moles-atoms-molecules, and all that
9/18/2009 1
Chem 105X
Wed. Sept. 18, 2009
Today
Tutors
Laboratory
1)Ionic and Covalent compounds
2)Formulas and names
3)Mixed nomenclature
4)Calculations:
a. moles-atoms-molecules, and all that
9/18/2009 2
Department of Chemistry and Biochemistry
Tutor is Jennifer Chambers
Room 170 Reichardt
Hours: Sept 21 thru Oct 2
Mon 12-2
Tues 2:45-3:45 and 5:15-8:00
Thurs 1-5:15
Fri 12-4
9/18/2009 4
Academic Advising Center’s
Supplemental Instruction (SI) Program
Robert Gorsline
Weekly review session
About 6 office hours, including some on
weekend.
(call 474-6396 for latest schedule)
9/18/2009 5
Laboratory next week
Introduction to Measurement Glassware and Use of Excel for Numerical Analysis
Please go to the Blackboard website for your lab procedure and pre-lab and lab report form. (demo)
9/18/2009 6
Review (1) monatomic ions1+
2+ 3- 2- 1-
1+ to 4+
Review (2) In compounds, Total + = Total -
9/18/2009 7
The compound between potassium and iodine
contains equal amounts of
K+
and I
- i..
. K
22+
and
I22.
.. K
2+ a
nd I2
- ...
K a
tom
s an
d I2
...84%
5%6%6%
1. K+ and I- ions
2. K22+ and I2
2- ions
3. K2+ and I2- ions
4. K atoms and I2 molecules
9/18/2009 8
The compound between potassium and iodine
contains equal amounts of
1. K+ and I- ions
2. K22+ and I2
2- ions
3. K2+ and I2- ions
4. K atoms and I2 molecules
Ionic compounds contain ions, not
atoms or molecules, which are
uncharged (neutral).
9/18/2009 10
� Cation name first…..Anion name
second
� Names DO NOT reflect the relative
numbers
� The relative numbers are INFERRED
from the ION CHARGES
� Transition metals and Sn,Sb,Pb,Bi
require ROMAN NUMERAL to indicate
charge
� Zinc (Zn) does NOT require a roman
numeral – it is always 2+
NaF sodium fluoride
K2O potassium oxide
lithium nitride Li3N
CoI2 cobalt (II) iodide
ZnI2 zinc iodide
9/19/2008 11
OWL and the text differ on name of the Ni2+ ion.
Kotz calls it “nickel (II)”
OWL calls it just “nickel” (because this is essentially the
only ion formed by Ni)
On exam I, if Ni is used, the charge will be
specified, and EITHER NAME will be an
acceptable answer.
9/18/2009 12
Polyatomic ions - like a molecule, but with total charge > or < 0.
All but two contain O, so they are called “oxoanions”.
+1 -1 -2 -3
NH4+ OH- (hydroxide)
NO2- (nitrite)
NO3- (nitrate)
ClO- (hypochlorite)
ClO2- (chlorite)
ClO3- (chlorate)
ClO4- (perchlorate)
CN- (cyanide)
CH3CO2- (acetate)
MnO4- (permanganate)
HCO3- (hydrogen carbonate)
HSO4- (hydrogen sulfate)
H2PO4- (dihydrogen phosphate)
CO32- (carbonate)
SO32- (sulfite)
SO42- (sulfate)
CrO42- (chromate)
Cr2O7
2- (dichromate)
HPO42- (hydrogen
phosphate)
PO43- (phosphate)
9/18/2009 13
You need to KNOW NAMES and FORMULAS of the
polyatomic ions on previous table. This is your chemistry
vocabulary. Table 2.4 p. 74 And Oxoanion Table on the course website.
Go to website
9/18/2009 15
What do these polyatomic anions look like? - Atoms tied together with covalent bonds in a definite geometry (as in a
molecule), but with 1 or more extra electrons.
- We’ll put off a discussion of the details of bonding until later in the semester, but here is a picture of the computed structure of HCO
3
-.
(see hydrogen carbonate
(bicarbonate) in HyperChem)
Approximate outer limit of electrons
The red color means that region is rich in
negative charge (slight excess of electrons). The
blue color indicates a region relatively poor in
electrons, “partially positive” is term sometime
used. The H of the OH group is like this.
9/18/2009 16
Ionic compounds with polyatomic ions obey same rules.
BUT: Need to RECOGNIZE THE ION(s) FROM THE
TABLE within the formula!
NH4NO2 contains one NH4+ and one NO2
- ion
per formula unit.
NaNO2 contains one Na+ and one NO2- ion
per formula unit.
9/18/2009 17
Naming also follows the same rules, including using roman
numeral for transition and lower main group atoms (but not zinc).
Calcium phosphate
(Always) Ca2+ (Always) PO43-
Balance charge using
lowest integer ratio: 3:2
Ca3(PO4)2
9/18/2009 18
Naming also follows the same rules, including using roman
numeral for transition and lower main group atoms (but not zinc).
Iron (III) nitrite
(Always) Fe3+ (Always) NO2-
Balance charge using
lowest integer ratio: 1:3
Fe (NO2)3
9/18/2009 19
CuHCO3
HCO3- anion
Therefore, this
must be the
Cu+ cation
Copper (I) hydrogen carbonate
Or Copper (I) bicarbonate
REQUIREDREQUIRED
9/18/2009 20
1.0 mole of sodium chloride contains
how many moles of IONS?
1. 2. 3. 4.
35%
1%6%
58%
1. 1.0
2. 2.0
3. 3.0
4. 4.0
9/18/2009 21
1.0 mole of sodium chloride contains
how many moles of IONS?
1. 1.0
2. 2.0
3. 3.0
4. 4.0
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
Na Cl-
A dozen formula
units of NaCl
contains 24 ions
1.0 mole of NaCl contains a mole (6.02x1023) NaCl
formula units. That is, a mole of each ion; total = 2
moles.
9/18/2009 22
1.0 mole of sodium carbonate contains
how many moles of IONS?
1. 2. 3. 4.
3%
17%
58%
21%1. 1.0
2. 2.0
3. 3.0
4. 4.0
9/18/2009 23
1.0 mole of sodium carbonate contains
how many moles of IONS?
1. 1.0
2. 2.0
3. 3.0
4. 4.0
Na2CO3
9/18/2009 25
“Binary” Covalent compounds - contain 2 kinds of atoms. The relative number of atoms is in general NOT PREDICTABLE.
So we just work back and forth between name and formula.
Names: DO INCLUDE PREFIX REFLECTING No. of atoms. The 2nd
atom is named like the monatomic ion (but its not an actual ion in the molecule…)
The element to RIGHT on the periodic table goes 2nd.
CO
CO2
C2O2
C3O2
etc
Carbon monoxide
Carbon dioxide
Dicarbon dioxideTricarbon dioxide
9/18/2009 27
What is the name of the compound with the formula SO3?
What is the name of the compound with the formula KNO3?
What is the formula for nickel chloride?
What is the formula for boron trichloride?
Sulfur trioxide
NiCl_2_
No metal or “NH4”! Therefore covalent
Group I metal is ALWAYS 1+! Therefore ionic.
��������
��������
��������
��������
This transition metal is ALWAYS 2+!
Therefore ionic.
No metal or “NH4”! Therefore covalent
Potassium nitrate
BCl_3_
9/18/2009 28
What ions – and their relative numbers - are
present in Li2SO4?
1. Two Li2+ and one SO44-
2. Two Li+, one S2-, and two O2 molecules
3. One Li22+, one S2-, and one O4 molecule
4. Two Li+ and one SO42-
5. One Li22+ and one SO4
2-
6. Need more information
9/18/2009 29
What ions – and their relative numbers - are present in Li2SO4?
1. Two Li2+ and one SO44-
2. Two Li+, one S2-, and two O2 molecules
3. One Li22+, one S2-, and one O4 molecule
4. Two Li+ and one SO42-
5. One Li22+ and one SO4
2-
6. Don’t know
(1) In any compound, a Group I metal M always forms M+ ion(2) “SO4” is the sulfate ion SO4
2- (simply by
memorization at this point)(3) No molecules “inside” polyatomic ions.