Week 3 Lab Report Measurements
Name Denisse Olivo
1. What is the importance of significant figures in chemistry? How are significant
figures determined in addition/subtraction? How are they determined in
The formula mass of ammonium phosphate is
Ammonium phosphate is (NH4)3PO4
3 x N + 12 x H + 1 x P + 4 x O
3x14.0 + 12x1.0 + 1x31.0 + 4x16.0 = 149.0 g/mol
Find the molecular(formula) mass of:
iron III chloride
Molecular Shape Affects a Substances Polarity.
Polar bonds effect the properties of a substance. Within a compound, polar
bonds may make the substance polar ORif symmetrically placed around
the molecule the polar bonds can cancel out the
Review of The Mole
We learned in a previous unit that:
1 mole = 6.022x1023 atoms = 1 Atomic Mass
This is still true for molecules:
1 mole = 6.022x1023 molecules = 1 Molar Mass
Optional-Isomers of Organics
C5.8b Draw isomers for simple hydrocarbons
C4.2e Given the formula for a simple hydrocarbon, draw and name the
We will limit our discussion to the halogen isomers of the alkanes for an
introduction to the isomers
Exceptions to Octet Rule (optional)
H, Be, B do not follow this rulewhy not?
Very Large, electronegative atoms (bigger than P) sometimes can hold more
than 8 electrons.
How Electrons are shared.3 ways
When one pair of s-sublevel electrons is sharedthe s-o
Polyatomic Lewis Structures
Lewis structures can also be drawn for polyatomic ions. You must take into
account the charge on the ion as well.
(-) charges add to the electrons,
(+) charges subtract from the number of electrons.
These structures are shown i
Do not use these prefixes with your ions.
CO2 is carbon dioxide (you knew this from Bio class)
CO is carbon monoxide
SO2 is sulfur dioxide
SO3 is sulfur trioxide (do Not confuse this with the sulfite ion, SO3 -2 )
N2O4 is dinitrogen
Outermost electrons wander freely through metal. Metal consists of
cations held together by negatively-charged electron "glue."
Free electrons can move rapidly in response to electric fields, hence
metals are a good condu
There are some substances we just call by the common names.
Strength of Bonds
C5.5d Compare the relative MP, electrical, thermal and hardness for ionic,
metallic and covalent compoun
Lewis Dot Families (not in packet)
C5.5c Draw Lewis structures for simple compounds.
Lewis structures show how atoms share electrons in order to complete their
octet of electrons in their outer shell.
Like Dissolves Like
DemoI2 solubility in Water, Alcohol, Veggie Oil
Nonpolar compounds dissolve other nonpolar compounds
Polar compounds dissolve polar compounds (and depending on polarity even
salts (ionic compounds)
The more similar t
A molecular orbital (a combination of each atoms orbitals where they overlap)
results from a covalent bond.
Formal Definition for Molecular Orbital:
the region of high probability that is occupied by an individual electron as it
Product bonds form
When the 4 O-H bonds form there is a great deal of energy released. In
addition the water molecules attract one another in forming H bonds (more
about this later)
The NET energy released is considered the overall energy change of the
Animation of salt dissolving
Consequences of H-Bonding
A. Water molecules are asymmetrical (not symmetrical) . The positively-charged
portions of one are attracted to the negatively-charged parts of another. It
takes a lot of energy to pull them apart.Soo
More Truth or Consequences
C. When water freezes, it assumes a very open structure and actually
expands. Most materials shrink when they freeze and sink in their liquid
If ice sank like most frozen solids, it would accumulate at the
Writing Names from Formulas
All of the substances named thus far are based on 2 or more simple ions.
These simple ions are also called monatomic ions (one atom ions)
These naming and formula princi
Energy of Salt Formation
It takes energy to ionize metals (endothermic).some energy is released
when non-metals are ionized, but normally a great deal of energy is released
when the ions actually combine This is called the lattice energy and is one
Cations(+) and anions(-) are attracted to one another by their opposite
A salt is an ionic compound formed by positive and negatively charged ions.
There are thousands of types of salt.
(Review Salt sampl
For Binary Ionic Compounds.
Ca+ions take the name of their element
Na+ = sodium ion, Al+3 = aluminum ion
When an element forms more than one charge, the ion includes roman
numerals to TELL THE CHARGE
Fe+2 is iron (II)
Fe+3 is Fe(III)
I=1, II = 2,