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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?

Section 2-1

Interest Grabber

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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

Section 2-1

Section Outline

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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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6

CCarbon12.011

Section 2-1

An Element in the Periodic Table

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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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2-1B1Atoms 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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Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14

6 electrons6 protons6 neutrons

6 electrons6 protons8 neutrons

6 electrons6 protons7 neutrons

Section 2-1

Figure 2-2 Isotopes of Carbon

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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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Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-)

Transferof electron

Protons +11Electrons -11Charge 0

Protons +17Electrons -17Charge 0

Protons +11Electrons -10Charge +1

Protons +17Electrons -18Charge -1

Section 2-1

Figure 2-3 Ionic Bonding

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Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-)

Transferof electron

Protons +11Electrons -11Charge 0

Protons +17Electrons -17Charge 0

Protons +11Electrons -10Charge +1

Protons +17Electrons -18Charge -1

Section 2-1

Figure 2-3 Ionic Bonding

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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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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

Section 2-2

Section Outline

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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 substancesMixed so well that you cannot see the difference between the substancesMade 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 OH- ions)

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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Oven cleaner

Bleach

Ammonia solution

Soap

Sea water

Human bloodPure waterMilkNormalrainfall

Acid rainTomatojuice

Lemon juice

Stomach acid

NeutralIn

crea

sing

ly B

asic

Incr

easi

ngly

Aci

dic

Section 2-2

pH Scale

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Cl-

Water

Cl-

Na+

Water

Na+

Section 2-2

Figure 2-9 NaCI Solution

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Section 2-2

Figure 2-9 NaCI Solution

Cl-

Water

Cl-

Na+

Water

Na+

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2–3 Carbon Compounds

A. The Chemistry of Carbon

B. Macromolecules

C. Carbohydrates

D. Lipids

E. Nucleic Acids

F. Proteins

Section 2-3

Section Outline

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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 RNAName Deoxyribonucleic

AcidRibonucleic Acid

Sugar 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 acidsc.20 amino acidsd.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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CarbonCompounds

include

that consist of

which contain

that consist of that consist of that consist of

which contain which contain which contain

Section 2-3

Concept Map

Carbohydrates Lipids Nucleic acids Proteins

Sugars and starches

Fats and oils Nucleotides Amino Acids

Carbon,hydrogen,

oxygen

Carbon,hydrogen,

oxygen

Carbon,hydrogen,oxygen, nitrogen,

phosphorus

Carbon,hydrogen,oxygen,

nitrogen,

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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

Section 2-4

Section Outline

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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