Download Matter - HCC Learning Web

INTRODUCTORY CHEMISTRY
Concepts & Connections
Fifth Edition by Charles H. Corwin
Chapter
4
Matter and
Energy
Christopher G. Hamaker, Illinois State University, Normal IL
© 2008, Prentice Hall
Matter
• Matter is any substance that has mass and
occupies volume.
• Matter exists in one of three physical states:
– Solid (s)
– Liquid (l)
– Gas (g)
Chapter 4
2
Gaseous State
• In a gas, the particles of matter are far apart and
uniformly distributed throughout the container.
• Gases have an indefinite shape and assume the
shape of their container.
• Gases can be compressed and have an indefinite
volume. They can be compressed into a liquid, like
liquid Nitrogen, N2(l) or a solid, like dry ice,
CO2(s).
• Gases have the most energy of the three states of
matter.
Chapter 4
3
Liquid State
• In a liquid, the particles of matter are loosely
packed and are free to move past one another.
• Liquids have an indefinite shape and assume the
shape of their container.
• Liquids cannot be compressed and have a definite
volume.
• Liquids have less energy than gases but more
energy than solids.
Chapter 4
4
Solid State
• In a solid, the particles of matter are tightly packed
together.
• Solids have a definite, fixed shape.
• Solids cannot be compressed and have a definite
volume.
• Solids have the least energy of the three states of
matter.
Chapter 4
5
Physical States of Matter
Chapter 4
6
Changes in Physical State
• Most substances can exist as either a solid, liquid,
or gas.
• Water exists as a solid below 0 °C; as a liquid
between 0 °C and 100 °C; and as a gas above
100 °C.
• A substance can change physical states as the
temperature changes.
Chapter 4
7
Solid ↔ Liquid Phase Changes
• When a solid changes to a liquid, the phase change
is called melting.
• A substance melts as the temperature increases.
• When a liquid changes to a solid, the phase change
is called freezing.
• A substance freezes as the temperature decreases.
Chapter 4
8
Liquid ↔ Gas Phase Changes
• When a liquid changes to a gas, the phase change
is called vaporization.
• A substance vaporizes as the temperature
increases.
• When a gas changes to a
liquid, the phase change is
called condensation.
• A substance condenses as
the temperature decreases.
Chapter 4
9
Solid ↔ Gas Phase Changes
• When a solid changes directly to a gas, the phase
change is called sublimation. Example: Moth ball.
• A substance sublimes as the temperature increases.
• When a gas changes directly to a
solid, the phase change is
called deposition.
• A substance undergoes
deposition as the
temperature decreases.
Chapter 4
10
Summary of State Changes
Chapter 4
11
Classifications of Matter
• Matter can be divided into two classes:
– Mixtures (also called solutions)
– pure substances
• Mixtures are composed of more than one
substance and can be physically separated into its
component substances.
• Pure substances are composed of only one
substance and cannot be physically separated.
Chapter 4
12
Mixtures
• There are two types of mixtures:
– homogeneous mixtures
– heterogeneous mixtures
• Homogeneous mixtures have uniform properties throughout.
– Beer; salt and water.
– Air.
– Alloy.
• Heterogeneous mixtures do not have uniform properties throughout.
– Sand and water.
– Sulfur and sand.
– Oil and water.
Chapter 4
13
Pure Substances
• There are two types of pure substances:
– compounds
– elements
• Compounds can be chemically separated into
individual elements.
– Water is a compound that can be separated into
hydrogen and oxygen.
• An element cannot be broken down further by
chemical reactions.
Chapter 4
14
Matter Summary
Chapter 4
15
Occurrence of the Elements
• There are over 100 elements that occur in nature;
81 of those elements are stable.
• Only 10 elements account for 95% of the mass of
the Earth’s crust:
Chapter 4
16
Elements In the Human Body
• Oxygen is the most common element in both the
Earth’s crust and in the human body.
• While silicon is the second most abundant element
in the crust, carbon is the second most abundant in
the body.
Chapter 4
17
***Elements in the Drugs and Human Body***
•
Tylenol (acetaminophen)Butyric acid (a saturated fatty acid)
CH3CH2CH2COOH
or CH3(CH2)2COOH
Cholesterol C27H46O,
the most common animal sterol (steriod alcohol).
Imuran (Azathioprine)
Chapter 4
18
Names of the Elements
• Each element has a unique name.
• Names have several origins:
– hydrogen is derived from Greek
– carbon is derived from Latin
– scandium is named for Scandinavia
– nobelium is named for Alfred Nobel
– yttrium is named for the town of Ytterby, Sweden
Chapter 4
19
Element Symbols
• Each element is abbreviated using a chemical
symbol.
• The symbols are 1 or 2 letters long.
• Most of the time, the symbol is derived from the
name of the element.
– C is the symbol for carbon
– Cd is the symbol for cadmium
• When a symbol has two letters, the first is
capitalized and the second is lowercase.
Chapter 4
20
Other Element Symbols
• For some elements, the chemical symbol is
derived from the original Latin name.
Gold – Au
Sodium – Na
Silver – Ag
Antimony – Sb
Copper – Cu
Tin – Sn
Mercury – Hg
Iron – Fe
Potassium – K
Tungsten – W
Chapter 4
21
***Macro- and micro-minerals***
In Basic Nutrition course:
• Macrominerals include those that are needed in high quantities,
ranging from milligrams (mg) to grams (g).
Examples are calcium (Ca), chlorine (Cl), phosphorous (P),
magnesium (Mg), sodium (Na) and sulfur (S).
• Microminerals or trace minerals are those necessary in smaller
quantities, generally between a microgram (mcg or µg) and a
milligram.
Examples are zinc (Zn), iron (Fe), manganese (Mn), copper (Cu),
iodine (I), chromium (Cr), selenium (Se), arsenic (As), boron (B),
cobalt (Co), fluorine (F), molybdenum (Mo), nickel (Ni), silicon (Si),
tin (Sn), and vanadium (V).
Chapter 4
22
Types of Elements
• Elements can be divided into three classes:
– Metals: Na, Mg, Al, Cr, Hg,…. etc.
Note: All metals are soild except Hg which is a liquid.
– Nonmetals: H, C, P, Cl, Ar,….etc.
– All nonmetals are either solid or gas except Br2 which is a
liquid.
– semimetals or metalloids: B, Si, Ge,….etc.
• Semimetals have properties midway between those of
metals and nonmetals.
Chapter 4
23
Metal Properties
• Metals are typically solids with high melting
points and high densities and have a bright,
metallic luster.
• Metals are good conductors of heat and electricity.
• Metals can be hammered into thin sheets and are
said to be malleable.
• Metals can be drawn into fine wires and are said to
be ductile.
Chapter 4
24
Nonmetal Properties
• Nonmetals typically have low melting points and low
densities and have a dull appearance.
• Nonmetals are poor conductors of heat and electricity.
• Nonmetals are not malleable or ductile and crush into a
powder when hammered.
• 11 nonmetals occur naturally in the gaseous state.
They are H2, N2, O2, F2, Cl2, He, Ne, Ar, Kr, Xe, Rn.
Chapter 4
25
Summary of Properties
Chapter 4
26
Periodic Table of the Elements
• Each element is assigned a number to identify it.
It is called the atomic number. It’s also called the
proton number.
• Hydrogen is 1; helium is 2; up to uranium, which
is 92.
• The elements are arranged by atomic number on
the periodic table.
Chapter 4
27
The Periodic Table
Chapter 4
28
Metals, Nonmetals, & Semimetals
• Metals are on the left side of the periodic table,
nonmetals are on the right side, and the semimetals
are in between.
Chapter 4
29
Physical States of the Elements
• Shown are the physical states of the elements at
25 °C on the periodic table.
Chapter 4
30
Law of Definite Composition
• The law of definite composition states that
“Compounds always contain the same elements in
a constant proportion by mass.”
• Water is always 11.19% hydrogen and 88.81%
oxygen by mass, no matter what its source.
• Ethanol is always 13.13% hydrogen, 52.14%
carbon, and 34.73% oxygen by mass.
Chapter 4
31
Chemical Formulas
• A particle composed of two or more nonmetal
atoms is a molecule.
• A chemical formula
expresses the number and
types of atoms in a molecule.
• The chemical formula of
sulfuric acid is H2SO4.
Chapter 4
32
Writing Chemical Formulas
• The number of each type of atom in a molecule is
indicated with a subscript in a chemical formula.
• If there is only one atom of a certain type, no ‘1’ is
used.
• A molecule of the vitamin niacin has 6 carbon
atoms, 6 hydrogen atoms, 2 nitrogen atoms, and
1 oxygen atom. What is the chemical formula?
C6H6N2O
Chapter 4
33
Interpreting Chemical Formulas
• Some chemical formulas use parentheses to clarify
atomic composition.
• Ethylene glycol, a component of some antifreezes,
has a chemical formula of C2H4(OH)2. There are 2
carbon atoms, 4 hydrogen atoms, and 2 OH units,
giving a total of 6 hydrogen atoms and 2 oxygen
atoms. How many total atoms are in ethylene
glycol?
• Ethylene glycol has a total of 10 atoms.
Chapter 4
34
Physical & Chemical Properties
• A physical property is a characteristic of a pure
substance that we can observe without changing
its composition.
• Physical properties include appearance, melting
and boiling points, density, conductivity, and
physical state.
• A chemical property describes the chemical
reactions of a pure substance.
Chapter 4
35
Physical & Chemical Change
• A physical change is a change where the chemical composition of the substance
is not changed.
These include changes in physical state or shape of a pure substance.
Simply put, you’ll always be able to get it back when a substance undergoes
physical changes by adjusting temperature, pressure, etc.
Example: Sublimation, melting, boiling, etc.
• A chemical change is a chemical reaction.
The composition of the substances changes during a chemical change.
Simply put, you cannot get it back when a substance undergoes a chemical
reaction.
Example: Boiling an egg, fruits ripe, nail rust, combustion (or burning or
explosion), decomposition, combination, oxidation-reduction, baking a potato,
color of carpet faded by sunlight, magnesium metal dissolves in vinegar to
produce hydrogen gas, etc. In nutrition, it’s metabolism or digestion.
Chapter 4
36
Evidence for Chemical Changes
• gas release (bubbles)
• light or release of heat energy
• formation of a precipitate
• a permanent color change
Chapter 4
37
Conservation of Mass
• Antoine Lavoisier found that the mass of
substances before a chemical change was always
equal to the mass of substances after a chemical
change.
• This is the law of conservation of mass.
• Matter is neither created nor destroyed in physical
or chemical processes.
Chapter 4
38
Conservation of Mass Example
• If 1.0 gram of hydrogen combines with 8.0 grams
of oxygen, 9.0 grams of water is produced.
• Consequently, 3.0 grams of hydrogen combine
with 24.0 grams of oxygen to produce 27.0 grams
of water.
• If 50.0 grams of water decompose to produce 45.0
grams of oxygen, how many grams of hydrogen
are produced?
50.0 g water – 45.0 g oxygen = 5.0 g hydrogen
Chapter 4
39
Potential & Kinetic Energy
• Potential energy, PE, is stored energy; it results
from position or composition. PE = mgh
• Kinetic energy, KE, is the energy matter has as a
result of motion. KE = ½ mv2
• Energy can be converted between the two types.
• A boulder at the top of the hill has potential
energy; if you push it down the hill, the potential
energy is converted to kinetic energy.
Chapter 4
40
Energy
Chapter 4
41
KE, Temperature, and Physical State
• All substances have kinetic energy no matter what
physical state they are in.
• Solids have the lowest kinetic energy, and gases
have the greatest kinetic energy.
• As you increase the temperature of a substance, its
kinetic energy increases.
Chapter 4
42
Law of Conservation of Energy
• Just like matter, energy cannot be created or
destroyed, but it can be converted from one form
to another.
• This is the law of conservation of energy.
• There are six forms of energy: heat, light,
electrical, mechanical, chemical, and nuclear.
Chapter 4
43
Energy and Chemical Changes
• In a chemical change, energy is transformed from
one form to another. For example:
Chapter 4
44
Law of Conservation of Mass & Energy
• Mass and energy are related by Einstein’s theory
of relativity, E = mc2.
• Mass and energy can be interchanged.
• The law of conservation of
mass and energy states that
the total mass and energy of
the universe is constant.
Chapter 4
45
Chemistry Connection: Al Recycling
• Although aluminum is very
abundant in the Earth’s crust,
it is difficult to purify it from
its ore.
• The energy from 8 tons of
coal is required to produce 1
ton of aluminum metal from
its ore.
• However, it only takes the
energy from 0.4 tons of coal
to produce 1 ton of aluminum
from recycled scrap.
Chapter 4
46
Chapter Summary
• Matter exists in three physical states:
– solid
– liquid
– gas
• Substances can be converted between the three
states.
• Substances can be mixtures or pure substances.
Chapter 4
47
Chapter Summary, continued
• Pure substances can be either compound or
elements.
• The elements are arranged in the periodic table.
• Each element has a name and a 1- or 2-letter
symbol.
• Elements are classified as either metals,
nonmetals, or semimetals.
Chapter 4
48
Chapter Summary, continued
• A physical change is a change in physical state or
shape.
• A chemical change is a change in the chemical
composition of a substance.
• Both mass and energy are conserved in chemical
and physical changes.
Chapter 4
49