kmhrmnmrm

1. www.unit5.org/chemistry
Energy and Matter
Unit 2

2. Guiding Questions
Why do substances boil or freeze at different temperatures?
Why do we put salt on the roads in the winter?
Why does sweating cool us?
What is energy?
How do we measure energy?

3. Table of Contents
‘Matter and Energy’
(13) Introduction - Bonding
(14) Temperature vs. Heat
(11) Density
(6) Carbon Dioxide & Monoxide
(4) Archimede’s Principle
(3) Galilean Thermometer
(11) Golf Ball Lab
(15) Solid, Liquid, and Gas
(3) Heating Curve
(13) Classification of Matter
(6) Crystalline Structure
(10) Allotropes
(9) Alloys
(4) Separation Techniques
(11) Distillation
(2) Centrifugation
(3) Electrolysis
(5) Properties of Matter
(6) Energy
(11) Exothermic vs. Endothermic
(29) Calorimetry
(12) Nuclear Energy

4. Lecture Outline – Energy and Matter
Keys
Lecture Outline – Energy and Matter
Lecture Outline – Energy and Matter
student notes outline
textbook questions
http://www.unit5.org/chemistry/Matter.html
textbook questions
text

5. Chemistry of Matches
P4S3 + KClO3 P2O5 + KCl + SO2
tetraphosphorus
trisulfide
potassium
chlorate
diphosphorus
pentaoxide
potassium
chloride
sulfur
dioxide
D
The substances P4S3 and KClO3 are both
present on the tip of a strike anywhere match.
When the match is struck on a rough surface,
the two chemicals (reactants) ignite and
produce a flame.
Charles H.Corwin, Introductory Chemistry 2005, page 182
Safety matches
The products from this reaction are P2O5, KCl, and SO2,the
last of which is responsible for the characteristic sulfur smell.
Strike anywhere matches
The substances P4S3 and KClO3
are separated. The P4S3 is on
the matchbox cover.
Only when the chemicals combine
do they react and produce a flame.

6. block of wood: length = 2.0 m width = 0.9 m height = 0.5 m
block of wood: force = 45 N
2.205 pounds = 1 kilogram 10 Newton (9.8 N)


7. Force versus Pressure
Area = 0.9 m x 2.0 m
= 1.8 m2
Area = 0.5 m x 2.0 m
= 1.0 m2
Area = 0.5 m x 0.9 m
= 0.45 m2
area
force
Pressure
2
m
1.8
N
45.0
Pressure 
2
m
1.00
N
45.0
Pressure 
2
m
0.45
N
45.0
Pressure
block of wood: length = 2.0 m width = 0.9 m height = 0.5 m
25 N/m2
45 N/m2
100 N/m2
Herron, Frank, Sarquis, Sarquis, Schrader, Kulka, Chemistry, Heath Publishing,1996, page Section 6.1

8. Pressure
area
force
pressure 
Which shoes create the most pressure?

9. During a
“physical change”
a substance changes
some physical
property…
H2O

10. …but it is still the
same material with
the same chemical
composition.
H2O
gas
solid
liquid

11. Chemical Property:
The tendency of a
substance to change into
another substance.
caused by iron (Fe)
reacting with oxygen (O2)
to produce rust (Fe2O3)
Steel rusting:
4 Fe + 3 O2 2 Fe2O3

12. Chemical Change:
Any change involving a
rearrangement of atoms.

13. Chemical Reaction:
The process of a
chemical change...

14. During a
“chemical reaction”
new materials are
formed by a change
in the way atoms are
bonded together.

15. Physical and Chemical Properties
Examples of Physical Properties
Boiling point Color Slipperiness Electrical conductivity
Melting point Taste Odor Dissolves in water
Shininess (luster) Softness Ductility Viscosity (resistance to flow)
Volatility Hardness Malleability Density (mass / volume ratio)
Examples of Chemical Properties
Burns in air Reacts with certain acids Decomposes when heated
Explodes Reacts with certain metals Reacts with certain nonmetals
Tarnishes Reacts with water Is toxic
Ralph A. Burns, Fundamentals of Chemistry 1999, page 23
Chemical properties can ONLY be observed during a chemical reaction!

16. The formation of a
mixture
The formation of a
compound

17. Physical & Chemical Changes
Limestone,
CaCO3
crushing
PHYSICAL
CHANGE
Crushed limestone,
CaCO3
heating
CHEMICAL
CHANGE
Pyrex
CO2
CaO
Lime and
carbon dioxide,
CaO + CO2

18. Pyrex
O2
H2O
Pyrex
H2O2
Light hastens the decomposition of hydrogen peroxide, H2O2.
The dark bottle in which hydrogen peroxide is usually stored
keeps out the light, thus protecting the H2O2 from decomposition.
Sunlight
energy

19. Three Possible Types of Bonds
+ -
d+ d-
Covalent
e.g. H2
Polar Covalent
e.g. HCl
Ionic
e.g. NaCl

20. Metallic Bonding
Metallic bonding is the attraction between positive ions and
surrounding freely mobile electrons. Most metals contribute
more than one mobile electron per atom.
“electron sea”
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
e1-
Free electrons
+
+
+
+
+
+
+
+
+
+
+
+
+
+
Cations
Bailar, Jr, Moeller, Kleinberg, Guss, Castellion, Metz, Chemistry, 1984, page 245

21. Shattering an Ionic Crystal; Bending a Metal
Bailar, Jr, Moeller, Kleinberg, Guss, Castellion, Metz, Chemistry, 1984, page 248
+ +
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+ + + + +
+ +
+ +
+
+
+ + + +
+ + +
+
+ +
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+ + + + +
+ +
+ +
+
+
+ + + +
+ + +
+
+
-
+ -
-
- +
+
- -
+
- +
+
-
+ -
-
+
+ -
+
-
- - -
+
+
-
+
+ - + - -
+ + -
+
-
+ -
-
- +
+
- -
+
- +
+
-
+ -
-
+
+ -
+
-
- - -
+
+
-
+
+ - + - -
+ + -
An ionic crystal
A metal
No electrostatic forces of repulsion –
metal is deformed (malleable)
Electrostatic
forces
of repulsion
Force
Force
broken crystal

22. Shattering an Ionic Crystal; Bending a Metal
Bailar, Jr, Moeller, Kleinberg, Guss, Castellion, Metz, Chemistry, 1984, page 248
+ +
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+ + + + +
+ +
+ +
+
+
+ + + +
+ + +
+
+ +
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+
+
+
+ +
+
+
+
+
+
+ +
+
+
+
+ + + + +
+ +
+ +
+
+
+ + + +
+ + +
+
+
-
+ -
-
- +
+
- -
+
- +
+
-
+ -
-
+
+ -
+
-
- - -
+
+
-
+
+ - + - -
+ + -
+
-
+ -
-
- +
+
- -
+
- +
+
-
+ -
-
+
+ -
+
-
- - -
+
+
-
+
+ - + - -
+ + -
An ionic crystal
A metal
No electrostatic forces of repulsion –
metal is deformed (malleable)
Electrostatic
forces
of repulsion
Force
Force
broken crystal

23. Properties of Ionic Compounds
• Crystalline solids
• Hard and brittle
• High melting points
• High boiling points
• High heats of vaporization
• High heats of fusion
• Good conductors of electricity when molten
• Poor conductors of heat and electricity when
solid
• Many are soluble in water

24. Chemical Bonds
Increasing ionic character
Covalent bonding
Electrons are shared
equally
Cl Cl
Polar covalent bonding
Electrons are shared
unequally
Cl
H
Ionic bonding
Electrons are
transferred
Cl1-
Na1+
Ralph A. Burns, Fundamentals of Chemistry 1999, page 229
• between two identical nonmetal atoms are non-polar covalent.
• between two different nonmetal atoms are polar covalent.
• between nonmetals and reactive metals are primarily ionic.

25. Chemical Bonds
Increasing ionic character
Nonpolar covalent
Electrons are shared
equally
Cl Cl
Polar covalent
Electrons are shared
unequally
Cl
H
Ionic bonding
Electrons are
transferred
Cl1-
Na1+
Ralph A. Burns, Fundamentals of Chemistry 1999, page 229
• between two identical nonmetal atoms are nonpolar covalent.
• between two different nonmetal atoms are polar covalent.
• between nonmetals and reactive metals are primarily ionic.

26. Covalent vs. Ionic
Covalent
Transfer
electrons
(ions formed)
+ / -
Between
Metal and
Nonmetal
Strong
Bonds
(high melting point)
Share
electrons
(polar vs. nonpolar)
Between
Two
Nonmetals
Weak
Bonds
(low melting point)
Alike Different
Electrons
are
involved
Chemical
Bonds
Ionic
Different
Topic Topic

27. Photoelectric
Generator
Solar Calculator
Radiant energy Evacuated
chamber
Metal
surface
Current
indicator
Positive
terminal
Voltage
source
cathode anode
Symbolic representation
of a photoelectric cell
cathode anode
evacuated glass
envelope
Photoelectric Cell