CHAPTER 4.
MATTER & ENERGY
CHM130
GCC
4.1 Three States of Matter:
solid, liquid, and gas
Gas: Particles are far apart and are in
constant motion.
– Gases have no set shape, they assume
shape of the container.
– Gases have no set volume, it is variable
If volume increases, particles move
farther apart.
If volume decreases, particles move
closer together.
Liquid: Particles are close together but are
free to flow around one another.
– Liquids assume shape of the container.
– Volume is constant (can’t compress).
Solid: Particles are packed tightly
together & organized in a rigid pattern;
the atoms vibrate in place.
– Solids have a definite, fixed shape.
– Volume is constant.
Cool animations
3 States Of Matter – Scroll down and click
on all the states of matter animations and
the phase change animation (some may not
work which is why there are several options)
Ways to Draw the States of Matter
physical changes – learn these 6 terms
4.2 Definitions
• Element – one type of atom only, can be
single atoms (He) or diatomic molecules
(O2), cannot be broken down further
chemically
• Compound – two or more different atoms
bonded together, can be broken down
chemically into elements
• Pure – all particles are the same, cannot be
physically separated
• Mixture – two or more different particles
mixed together, can be physically separated
(top picture is pure element, bottom is pure compound)
Examples
•Mixtures
• Metal alloys like 18-K gold, brass
• Sand, granite
• Tap water
• Air which consists of nitrogen, oxygen,
and other trace gases.
•Pure
• Salt (NaCl) is a compound
• Diamond (carbon) is an element
• Distilled water is a compound
• Mercury is an element
element
compound
mixture
A = element
B = cmpd
C = mix
D = element
E = cmpd
F,G = mix
H = element
For each figure, indicate if it represents
an element, a compound, or a mixture
4.3 Elements
1. Each element has a unique name, symbol,
and number
2. Capitalize first letter of element name:
hydrogen H, carbon C
3. If there’s a 2nd letter it is lower case: helium
He, calcium Ca, cobalt Co
Careful! CO is carbon monoxide not cobalt
Most symbols are from English names:
hydrogen H; oxygen O; Helium He
Some are from Latin names:
lead Pb (plumbum)
gold Au (aurum means “golden dawn”)
KNOW THE NAMES AND SYMBOLS
OF THE FIRST 20 ELEMENTS
OF THE PERIODIC TABLE
& THE FOLLOWING
Ag silver
Au gold
Pb lead
Br Bromine
I iodine
Hg mercury
Periodic Table: You already know many of these
Let’s name them!
4.4 nonmetals, semimetals, and metals
(Fig. 4.5)
1. Nonmetals (except H) are located on the right
side of the stair-step line
2. Semimetals are touching the stair-step line
following B (except Al which is metal)
3. Metals are on the left side of the stair-step line
Properties of Metals vs. Nonmetals
Metals
Nonmetals
shiny appearance
dull appearance
malleable, ductile
Brittle solids
All solids but Hg
Many gases
density – usually high density – usually low
melting point - high
melting point low
Good conductors of Poor conductors (make
heat & electricity
better insulators)
Semimetals (metalloids)
Have properties in between
Physical States of the Elements at 25 ˚C
and normal atmospheric pressure
KNOW THESE
Only mercury (Hg) and bromine (Br2)
are liquids
H2, N2, O2, F2, Cl2, and all Noble gases
(Group VIIIA) are gases
All other elements are solids
Physical States of the elements
04_06.JPG
7 Diatomic elements
Diatomic means two atoms bonded
together
Have no fear of ice cold Beer!
H2(g) N2(g) F2(g) O2(g) I2(s)
Cl2(g) Br2 (l)
Two Diatomic Elements
Bromine Br2(l) and Iodine I2(s)
I should be able to point at any
element and you tell me
1. Solid, liquid, or gas
2. Name (for some of them)
3. Diatomic or not
4. Metal, semimetal, nonmetal
Let’s play! I’ll point at several
elements…
This is how we draw
Atoms of an Element
2 or more atoms bonded together =
Molecules of an Element if same
Molecules of a Compound if different
4.5 Chemical formulas tell us
- type of atoms = element symbols
- # of those atoms = subscripts (don’t show 1)
-But NOT their bonding order
Ex: water = H2O 2 H atoms, 1 O atom
but water is not bonded H-H-O
Ex: How many atoms in potassium nitrate = KNO3
3 O atoms
1 K, ___
1 N, ___
___
but it is not bonded K-N-O-O-O
Another
Example
Ex: (NH4)3PO4
What is the total number of atoms?
(NH4)3 = 3 NH4’s = 3 ( 1 N + 4 H) = 3N + 12 H
TOTAL: 3 N, 12 H, 1 P and 4 O’s = 20 atoms
How many atoms of each element are
present in Viagra: C22H30N6O4S ?
6 N, ____O,
30 H, ___
1
22 C, ____
4
____
_____S
Law of Definite Composition
Compounds always contain the same
elements in the same proportion by
mass.
Ex: H2O always contains 11.2 % H and
88.8 % O by mass whether you have a
glass full, a swimming pool or an ocean.
4.6 Physical properties
- color, odor, taste, texture, melting
point, physical state (s, l, or g), density,
solubility, conductivity, hardness
Chemical properties - describe how a
substance reacts or behaves. (explosive,
corrosive, toxic, inert, reactive, rusts,
oxidizes, decomposes, etc.)
4.7 Physical change: a change that
keeps chemical composition the same,
the molecules stay the same with the
SAME formula.
Physical Changes ARE changes in state
(s D l D g)
Ex: boiling water, melting gold, freezing
alcohol, breaking glass, dissolving salt in
water, dry ice subliming
Note that the H2O molecules remain
H2O regardless of whether the sample
is a solid, liquid, or gas; changes in
physical state are physical changes
Review
Physical
Changes
– know
these
terms!
Physical Changes
 Atoms are always moving, even in solid state.
 When you heat ice, the water particles gain
kinetic energy and move faster.
 When particles gain enough energy to overcome
attractive forces the solid will melt  liquid.
 If we keep heating the liquid, the particles gain
more KE & move even faster  gaseous state
Chemical Changes: a process that changes the
chemical composition, the molecules break apart
and rearrange. The formula CHANGES.
(aka chemical reactions)
Starting substance is destroyed and a
new substance with different properties
is formed.
Ex: burning
gas
Indicators of chemical reaction:
These may indicate chemical change
• oxidation of matter (burning or rusting)
• release of gas bubbles (fizzing) without
heating (thus not boiling)
• formation of solid (precipitation)
• release of heat or light
• change in color or odor
CHEMICAL REACTIONS
REACTANTS  PRODUCTS
Starting substances are called reactants;
New substances formed are called
products.
Ex:
2 H2 + O 2
 2 H2O
Ex: Chemical
reaction between
sodium metal Na(s)
and chlorine gas
Cl2(g). They produce
salt, NaCl, which is a
totally different
chemical with
different formula and
properties than the
reactants.
4.8 LAW OF CONSERVATION OF MASS
Matter or mass cannot be created or destroyed
mass of the reactant(s) = mass of the product(s)
Two reactants make 4.0 grams of product. If one
reactant was 1.5 grams, the other was ________
2.5 g
4.9 Kinetic Energy - Energy of
motion
Examples
Water flowing over a dam
Working out
Dancing
Burning gasoline
Potential Energy- Stored Energy
Examples
 Water behind a dam
 Gasoline or coal
 Chemical bonds in food
 Car at top of roller coaster
KE, Temp, and physical state
• As kinetic energy increases and molecules
move and vibrate faster, the temperature
increases
____________.
As kinetic energy increases
a solid will eventually turn into a
liquid
____________.
And as the KE increases
even more it will eventually turn into a
gas
____________.
• KE and T are related directly or indirectly?
• Which state of matter has lowest KE? solid
Highest? gas
4.10 Law of Conservation of Energy
Energy cannot be created or destroyed,
only converted from one form to another.
Ex: When we digest food its stored
energy (potential) is converted to kinetic
energy to do work.
6 Other Forms of Energy
 Radiant (light, UV, radiowaves, etc.)
 Heat
 Chemical (stored in bonds)
 Electrical
 Mechanical
 Nuclear
Chapter 4 Self Test
Page 107
•Try # 1, 4-11, 14-16
•Answers in Appendix J