Transcript Presentation

Interest Grabber
Section 2-1
What’s the Matter?
1. Give an example of solid matter.
2. Give an example of liquid matter.
3. Give an example of gaseous
matter.
4. Is all matter visible?
5. Does all matter take up space?
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Section:
Section Outline
Section 2-1
2–1The Nature of Matter
A.
Atoms
B.
Elements and Isotopes
1.
Isotopes
2.
Radioactive Isotopes
C.
Chemical Compounds
D.
Chemical Bonds
1.
Ionic Bonds
2.
Covalent Bonds
3.
Van der Waals Forces
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2-1a. Atoms
Basic units of matter. – Once previously
thought to be indivisible.
“atomos” – Unable to cut
Democritus – 2500 years ago; thought up
the idea of atoms and named them
100 million atoms in a row is about 1cm
long
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Subatomic Particles:
Protons – positively charged particles;
part of the nucleus
Neutrons – carry no charge; have mass;
are part of the nucleus
Electrons – negatively charged particles
the surround the nucleus
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Protons and neutrons have about the
same mass. Bound together in the center
of the atom (nucleus)
The electron is much smaller (1/1840 of
the size of a proton). They are constantly
in motion. They are attracted to the
positive charge of the nucleus but remain
outside because of their energy.
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Atoms are considered to be
neutral because there is an
equal number of protons and
electrons. (opposite charges)
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2-1b Elements and Isotopes
Elements are pure substances that
consist entirely of one type of atom.
Elements are represented by a one or two
letter symbols and presented on the
Periodic Table.
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An Element in the Periodic Table
Section 2-1
6
C
Carbon
12.011
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The number above the symbol is called
the atomic number. It tells you the
number of protons in an atom and
consequently, the electrons.
The bottom number is called the mass
number. It tells the mass of the nucleus,
or the mass of protons and neutrons.
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2-1B1
Atoms of an element can have
different numbers of neutrons.
If they do differ in the number of
neutrons, they are called isotopes.
We identify isotopes by their mass
number.
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Atomic mass is a weighted average
of the different isotopes.
All isotopes have the same chemical
properties because they have the
same number of electrons.
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2-1 B2.
Some isotopes are radioactive, meaning
their nuclei are unstable and break down
at a constant rate.
Practical uses: fossil / rock dating
Treating cancer and killing bacteria
Used as tracers to follow movements of
substances.
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Figure 2-2 Isotopes of Carbon
Section 2-1
Nonradioactive carbon-12
Nonradioactive carbon-13
6 electrons
6 protons
6 neutrons
6 electrons
6 protons
7 neutrons
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Radioactive carbon-14
6 electrons
6 protons
8 neutrons
2-1C – Chemical Compounds
A chemical compound is a substance
formed by the chemical combination of
two or more elements in definite
proportions.
The physical and chemical properties of a
compound are very different from the
elements that form it. (sodium and
chlorine page 37)
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2-1D Chemical Bonds
Bonds hold the atoms in compounds
together. The formation of bonds involves
electrons that surround each nucleus.
The electrons involved with bonding are
called valence electrons.
The main types of bonds are ionic and
covalent.
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2-1D1 – Ionic Bonds
An ionic bond is formed when one or
more electrons are transferred from one
atom to another.
An atom that loses an electron becomes
positive. An atom that gains an electron
becomes negative.
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The positively and negatively charged
atoms are now called ions.
Oppositely charged ions have a strong
attraction called an ionic bond.
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Figure 2-3 Ionic Bonding
Section 2-1
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
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Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
Figure 2-3 Ionic Bonding
Section 2-1
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
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Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
2-1 D2 – Covalent Compounds
Covalent bonds occur when electrons are
being shared between two or more atoms.
You can have single, double, or triple
bonds.
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The structure that results when atoms are
joined together by covalent bonds is
called a molecule.
A molecule is the smallest unit of most
compounds.
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Sharing among covalent bonds is not
always equal.
The unequal sharing causes slight
positive and negative attractions.
The attractions are called van der Waal
forces.
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Energy Levels
Distinct regions around the nucleus where
electrons are found
1. Octet Rule – the outermost level (for
stability purposes) will not hold more or
less than 8 electrons
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Section Outline
Section 2-2
2–2 Properties of Water
A.The Water Molecule
1. Polarity
2. Hydrogen Bonds
B.Solutions and Suspensions
1. Solutions
2. Suspensions
C.
Acids, Bases, and pH
1. The pH Scale
2. Acids
3. Bases
4. Buffers
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2a – The Water Molecule
Water is the single most abundant
compound in most living things.
Unique: Water expands as it freezes
which changes its volume and explains
why ice floats on water.
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2A-1 Polarity
Water is a neutral compound; 10 protons
and 10 electrons
Oxygen has a greater attraction for
electrons than hydrogen does.
It is polar because there is an uneven
distribution between the oxygen and
hydrogen atoms.
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2A-2 Hydrogen Bonds
They form between the positive charge of
hydrogens and the negative charge of the
oxygen on the adjacent molecule.
Not as strong as ionic or covalent, but the
strongest between adjacent molecules.
Can have up to 4 hydrogen bonds at any
time, which gives water its properties.
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continued
a.Cohesion – attraction between
molecules of the same substance; ex.
Drops of water on the surface; why
insects can walk on water
b.Adhesion - attraction of molecules of
different substances; meniscus of
water- attracts to glass
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2B. Intro
A mixture is a combination of substances
that are not chemically bonded and they
do not have a set ratio
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2B-1 Solutions
A uniform mixture of two or more
substances
Mixed so well that you cannot see the
difference between the substances
Made of two Components: 1. solute –
dissolved substance. 2. solvent –
dissolving substance (water = universal
solvent)
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2B -2 Suspensions
Mixtures of water and undissolved
materials.
EX. Blood – solution because it contains
water which dissolve many compounds,
Suspension because it contains cells that
do not settle out.
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2C-1 pH scale
A standard measurement of the
concentration of the H+ ions in a
solution
Numbered from 0-14
0=highly acidic; 14=highly basic
Each step represents a factor of 10
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2C-2 Acids
Any compound that forms H+
ions in solution
Strong acids usually have a pH of
0-3
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2c-3 Bases
Contain lower concentrations of H+
ions than pure water (produces OHions)
Strong bases usually have a pH of
11-14
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2C-4 Buffers
Fluids in the human body must have
a pH between 6.5 and 7.5 (except
stomach acid – 2)
Buffers are weak acids or bases that
react with strong acids or bases to
prevent sharp, sudden changes in
pH
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pH Scale
Section 2-2
Increasingly Basic
Oven cleaner
Increasingly Acidic
Neutral
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Bleach
Ammonia solution
Soap
Sea water
Human blood
Pure water
Milk
Normal
rainfall
Acid rain
Tomato
juice
Lemon juice
Stomach acid
Figure 2-9 NaCI Solution
Section 2-2
ClCl-
Na+
Na+
Water
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Water
Figure 2-9 NaCI Solution
Section 2-2
ClCl-
Na+
Na+
Water
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Water
Section Outline
Section 2-3
2–3 Carbon Compounds
A.
The Chemistry of Carbon
B.
Macromolecules
C.
Carbohydrates
D.
Lipids
E.
Nucleic Acids
F.
Proteins
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2-3A The Chemistry of Carbon
Carbon has four valence electrons
allowing it to bond with many other
elements, including itself
Carbon can form many different large
and complex structures (diamonds,
graphite)
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2-3B Macromolecules
1.Monomer – small building block of
organic molecules
2.Polymer – linking of 2 or more
monomers
3.When a polymer becomes thousands of
monomers long, it is also called a
macromolecule
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2-3C Carbohydrates
Compound composed of carbon,
hydrogen, and oxygen 1:2:1 ratio
Supplies immediate energy for all cell
activities
Extra sugar is stored as complex
carbohydrates called starches
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Carbohydrates continued…
Sugars:
1.Monosaccharides – simplest carbs;
contain3,5 or 6 carbon atoms; glucose,
fructose
2.Disaccharides – sugars made of two
covalently bonded monosaccharides;
sucrose, lactose
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Continued
3. Polysaccharides – giant polymers that
consist of thousands of linked
monosaccharides; glycogen
4. Plant starch – used to store extra sugar
and give plants strength and flexibility;
cellulose
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2-3D Lipids
Do not dissolve in water; made of carbon
and hydrogen atoms
Types: 1. fats – compounds composed of
glycerol and fatty acids; energy and
storage
2. Phospholipids – contain phosphate; cell
membranes
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continued
3. Steroids – lipids composed of four
linked rings of carbon atoms; chemical
messengers
Cholesterol
Hormones – special chemicals produced
in one part of the body that controls the
functions of other parts of the body
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Lipids continued….
4. Waxes – composed of fatty acids and
alcohols; waterproofing
The chemistry of fats:
1. Fatty acid – compounds consisting of a
chain of carbon atoms with an acid group
at one end
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Fats continued…
2. (2) Types of Fats
a.Saturated fats – the molecules is
completely saturated with hydrogen
atoms; solid at room temperature
b.Unsaturated fats – the molecule
contains double bonds where
hydrogens are in saturated fats; liquid at
room temp
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2-3E – Nucleic Acids
1.Large complex molecules composed of
carbon, hydrogen, oxygen, nitrogen,
and phosphorus; store and transmit
hereditary information
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2. Polymers of nucleotides
A nucleotide is a 5-carbon sugar, a
nitrogen containing base, and a
phosphate group
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3. (2) Types of Nucleic Acids
DNA
Name
Sugar
RNA
Deoxyribonucleic Ribonucleic Acid
Acid
Deoxyribose
Ribose
Bases
A, G, C, T
A, G, C, U
Shape
Double Stranded
Single Stranded
Function
Controls Cell
Activites
Builds Proteins
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Adenine – DNA, RNA
Guanine – DNA, RNA
Cytosine – DNA, RNA
Thymine - DNA
Uracil - RNA
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2-3 F Proteins
Compounds composed of carbon,
hydrogen, oxygen, nitrogen, and
sometimes sulfur
Structure:
(1.) Amino acids – a compound that
contains an amino group, a carboxyl
group, and a side group
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Protein structure continued:
a.The side group determines the type of
amino acid
b.All proteins are polymers of amino acids
c.20 amino acids
d.Held together by peptide bonds;
polypeptide chain (covalent bond
between amino acids)
e.Sequence is very important
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Proteins continued:
Functions of proteins:
a.Movement – muscles
b.Structure – connective fibers (collagen,
keratin)
c.Biochemical control – enzymes
d.Transport – hemoglobin
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e. Storage – storage of amino acids in
baby animals
f. Regulation - insulin (controls sugar in
the blood)
g. Defense - antibodies
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Concept Map
Section 2-3
Carbon
Compounds
include
Carbohydrates
Lipids
Nucleic acids
Proteins
that consist of
that consist of
that consist of
that consist of
Sugars and
starches
Fats and oils
Nucleotides
Amino Acids
which contain
which contain
Carbon,
hydrogen,
oxygen
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Carbon,
hydrogen,
oxygen
which contain
which contain
Carbon,hydrogen,
oxygen, nitrogen,
phosphorus
Carbon,
hydrogen,oxygen,
nitrogen,
Section Outline
Section 2-4
2–4 Chemical Reactions and Enzymes
A.Chemical Reactions
B.Energy in Reactions
1. Energy Changes
2. Activation Energy
C.
Enzymes
D.
Enzyme Action
1. The Enzyme-Substrate Complex
2. Regulation of Enzyme Activity
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2-4 A Chemical Reactions
Chemical reactions – process that
changes one set of chemicals into
another set of chemicals
All things that happen in an organisms are
dependent on chemical reactions
EX. Growth, interaction with the
environment, reproduction, movement
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Parts of a chemical reaction
1.Reactants – elements or compounds
that enter into a reaction
2.Products – elements or compounds
produced by a chemical reaction
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2-4 B Energy in Reactions
Energy Changes:
1.(exothermic) Chemical reactions that
release energy often occur
spontaneously. Energy released as heat,
light, or sound
2. (endothermic) Chemical reactions that
absorb energy will not occur without a
source of energy.
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Animals and plants must obtain energy
either by food or sunlight.
Activation energy – the energy needed to
get a reaction started
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2-4 C Enzymes
1.Some chemical reactions are too slow
to be useful. (The required activation
energy is too high.)
2.Catalyst – substance that speeds up a
chemical reaction without changing the
reactants or products by lowering the
activation energy
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Enzymes – proteins that act as biological
catalysts
There are specific enzymes for specific
reactions.
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2-4 D Enzyme Action
The Enzyme-Substrate Complex
1.Enzymes provide a place for the
reactants (substrates) and the products
of a reaction to meet so they can react.
2.Substrates bond to the active site on the
enzyme.; Lock and Key
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Regulation of Enzyme Activity
1.How and when Enzymes work
a. certain pH
b. certain temperature
c. proteins can turn enzymes on or off
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2. Regulation of Body Activities
a.Chemical pathways
b. Making materials the cells need
c. Releasing energy
d. Transferring information
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