Unit 2: What is the
most important
substance?
Lesson 1:
 Review of Unit 1,
 Term Plan
 Introduction into unit 2,
What’s common from Unit 1 into Unit 2
• S2.6 – Ionic bonding occurs when
positive and negative ions are held
together in a crystal lattice by
electrostatic forces
• R3.2 – Every chemical reaction can be
represented by balanced equation,
whose coefficients indicate both the
number of reacting particles and the
reacting quantities in moles
• R3.3 – A balanced equation can be
used when determining whether
reagents are limiting or in excess
• R3.4 – The use of molarity for
expressing concentration allows easy
interconversions between volume of
solution and moles of solute
Quick Review
There are 2 major types of bonding
Ionic bonding – When a metal gives
1. ________
one (or more) electron/s to a non-metal.
Covalent bonding – When two non2. _________
metals ‘share’ an electron.
Example of Ionic Bonding
Quick Review
Ionic
What Type of bonding is this?
Quick Review
COVALENT BONDS
• Easiest way to figure out covalent bonds is
through Lewis DOT Diagrams.
• The number of dots around the element is
determined by what GROUP it’s in:
1
2
3
4
5
6
7
8
Li
Be
B
C
N
O
F
Ne
• The elements in the groups 3 and up want to
have 8 electrons (dots) around them
Single Covalent bond
HEY LETS SHARE AN ELECTRON
ITone
LOOKS LIKE
WE”VE
IEACH
wish ISO
had
I wish
I had one
GOT
EACHmore
!!! electron so I’d
more electron
so 8I’d
have 8
have 8
Cl
Cl
DOUBLE Covalent bond
HEY LETS SHARE 2 ELECTRONs
EACH SO IT LOOKS LIKE WE”VE
GOT 8 EACH !!!
O
O
Quick Review
#
particles
MASS
#
MOLES
#
MOLES Molecular
Weight
÷ (molecular weight)
x (molecular weight)
6.02 X 1023
x (6.02 X 1023)
÷ (6.02 X 1023)
Quick Review
The Mole Roadmap
Volume of
Gas (L)
 6.02 1023
 22.4
Representative
Particles
 6.02 1023
 22.4
Moles
(mol)
MW
 MW
Mass
(g)
Quick Review
Concentration (C)
• Molarity of a solution is the
number of moles of solute per
litre of solution.
– i.e. 0.5M solution contains 0.5mol
of the substance per litre.
Mols
C
V
What’s New in Unit 2
• S2.8 – Forces weaker than covalent bonding
exist between molecules
• S2.2 – The macroscopic properties are related to
their microscopic and atomic properties
• R3.4 – The use of molarity for expressing
concentration allows easy interconversions
between volume of solution and moles of solute
• R1.3 – Acid-base reactions involve transfer of
protons from donors to acceptors
• R4.1 – Techniques such as volumetric and
gravimetric analysis are used to determine
amounts of reactants and products
• R4.2 – Specialised techniques and
instrumentation are used in chemical analysis
• R4.3 – Qualitative and quantitative testing may
be used to determine the composition of type of
material
Term 2 Outline
Homework Reading
• Pg 39 – 42
• Density
• Shape of water
• Structure of ice
• Pg 45 – 53
• Dissolving salts and ions
• Effects of solutes upon melting and
boiling points of water
• Isotonic, hypotonic, hypertonic
CLICK VIEW
Water & the Water Cycle