DOCSLIB.ORG

Chemical Bonds and Equations

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Chemical Bonds and Equations Chemical Bonds And Equations Intro to Chemical Bonds EQ: Why do atoms have a strong desire to form chemical bonds in nature? What are these called when different types of atoms bond to form a chemically different substance? Compound – substance made of the combined atoms of two or more elements. Chemical formula – tells what elements a compound contains and the exact number of the atoms of those elements Some Common Compounds Vinegar Acetic acid HC2H3O2 Sand Silicon dioxide SiO2 Stomach Hydrochloric HCl Acid acid Cane Sugar Sucrose C12H22O8 Superscript – represents 2H2O oxidation # or 2- how many Coefficient SO4 – represents the # electrons has of units of each gained or lost substance Subscripts – represents # of atoms in a molecule of a particular element Atoms form compounds to become chemically stable. An atom is chemically stable when the outer energy level is complete, or full. (Why it is hard to find these elements alone / unbonded.) Chemical bond – force that holds together the atoms in a substance ION – positive or negatively charged atom Ionic Bond vs. Covalent Bond loses or gains electrons shares electrons attraction between can form multiple bonds opposite charges of ions between a nonmetal and another nonmetal between metal & nonmetal nonmetals EQ Answer: Compounds have different properties than the atoms that male them up. Atoms form compounds to create a chemically stable molecule or compound. The chemical bonding stabilizes atoms by filling their outer most shell (valence). Writing Formulas and Naming Compounds Binary compound – compound composed of two elements Oxidation number – positive or negative number (on PTable) which indicates how many electrons an element has gained, lost or shared when bonding with another atom. * When writing a formulas for binary ionic compounds, it is important to remember that compounds formed have a net charge of zero. POLYATOMIC IONS Charged Name Formula Polyatomic Ions a positively or group of 1+ Ammonium NH4+ - atoms negatively charged 1- Acetate C2H3O2 covalently bonded - 1- Chlorate ClO3 1- Hydroxide OH- 1- Nitrate NO - The prefix poly means 3 2- Carbonate CO 2- “many”, so the term 3 2- Sulfate SO 2- polyatomic means 4 3- Phosphate PO 3- “having many atoms” 4 Hydrate – a compound that has water chemically attached to its ions and written into chemical formula. Covalent compounds – can form more than one compound with each other. Scientist use Greek prefixes to indicate # of atoms of each element in binary compound. Prefixes For Binary Covalent Compounds #atoms 1 2 3 4 5 6 7 8 prefix Mono- di- tri- tetra penta hexa hepta octa Chemical Reactions Chemical reaction - a reaction in which one or more are changed to new substances Reactants - substances that are about to react Produced Products - new substances Reactants Products produced Law of Conversation of Mass – total starting mass of all reactants equals the total final mass all products. Chemical equation - uses chemical formulas and symbols to describe a chemical reaction and the product it produces (see below) Symbol Meaning Symbol Meaning produces or (aq) Aqueous (solid yields dissolved in H2O) + plus Heat Reactants heated (s) solid Light Reactants exposed to light (l) liquid Elec Electric current (g) gas Applied to reactants Coefficients – #’s which represents the number of units of each substance in a rxn 4Al (s) + 3O2 (g) 2Al2O3 Subscripts – #’s which represent the number of atoms in a molecule of a particular element BALANCING CHEMICAL EQUATIONS Balanced chemical equations – have the same number of atoms of each element on both sides of equation * When balancing chemical equation NEVER change the subscripts, instead change the coefficient in front of the compounds needing balanced. Steps to Balancing a Chemical Equation Step 1: Write a chemical equation for the reaction using formulas and symbols – make sure reactants are on left side and products on right. Step 2: Count the atoms in reactants and products. Step 3: Choose coefficients that balanced the equation. HINT: Generally, if there is an even # of an element on one side and an odd on the other side, place a 2 in front of compound containing odd number of atoms. Step 4: Recheck the numbers of each atom on both sides of and adjust coefficients if necessary – remember NEVER change subscripts. Ex. 2NaBr + Cl2 2NaCl + Br2 STEP 3 STEP 1 Na 1 2 1 2 Br 1 2 2 Cl 2 1 2 STEP 2 STEP 4 CHEMICAL REACTION TYPES Synthesis reaction - reaction where two or more substances combine to form another substance A+B AB Decomposition reaction - reaction where one substance breaks down, or decomposes, into two or more simpler substances AB A+B Double – displacement reaction - reaction that results in a precipitate, water or gas when a positive ion of one compound swaps with another positive ion of another compound. AB + CD AC + BD Single – displacement reaction - reaction in which one element replaces another in a compound A + B AC + B or A + BC AB + C CHEMICAL REACTIONS –RATES AND ENERGY • To determine if the overall reaction releases or absorbs energy, you must compare the energy content of the reactants and the products. • Exothermic reaction - releases energy; reactants contain more energy than the products. (reactants = products + energy) Ex: Zn + 2HCl → ZnCl2 + H2 + energy Ex. burning wood, fireworks • Endothermic Reaction - Absorbs energy; products contain more energy than the reactants. (reactants + energy = products) • Energy must be applied to get the reaction going. Energy will appear on the reactants side of the equation. • Ex: 6 CO2 + 6 H2O + energy → C6H12O6 + 6 O2. Ex. Chemical Ice pack, photosynthesis Rate of Reaction – Speed at which reaction occurs or new substances form. Activation Energy • Activation energy is the energy that molecules need to break the bonds and begin the reaction. • Sources for AE can be friction, electricity, light, etc. • The rate at which molecules come into contact with each other determines the reaction rate. This is known as the “collision theory”. • There are 3 factors that influence the rate at which particles run into each other: • 1. Temperature – The higher the temperature the faster the particles move. • 2. Concentration – The greater the concentration of the reactants, the more particles there are to collide. • 3. Surface Area - As surface area increases (crushing) there are more reactant particles exposed. Other factors that affect reactions… Catalyst – speeds up a chemical reaction without itself being permanently changed (lowers activation energy) Inhibitor – prevents or slows a chemical reaction or interferes with the catalyst.
Load more

Recommended publications
  • Constraint Closure Drove Major Transitions in the Origins of Life
    entropy Article Constraint Closure Drove Major Transitions in the Origins of Life Niles E. Lehman 1 and Stuart. A. Kauffman 2,* 1 Edac Research, 1879 Camino Cruz Blanca, Santa Fe, NM 87505, USA; [email protected] 2 Institute for Systems Biology, Seattle, WA 98109, USA * Correspondence: [email protected] Abstract: Life is an epiphenomenon for which origins are of tremendous interest to explain. We provide a framework for doing so based on the thermodynamic concept of work cycles. These cycles can create their own closure events, and thereby provide a mechanism for engendering novelty. We note that three significant such events led to life as we know it on Earth: (1) the advent of collective autocatalytic sets (CASs) of small molecules; (2) the advent of CASs of reproducing informational polymers; and (3) the advent of CASs of polymerase replicases. Each step could occur only when the boundary conditions of the system fostered constraints that fundamentally changed the phase space. With the realization that these successive events are required for innovative forms of life, we may now be able to focus more clearly on the question of life’s abundance in the universe. Keywords: origins of life; constraint closure; RNA world; novelty; autocatalytic sets 1. Introduction The plausibility of life in the universe is a hotly debated topic. As of today, life is only known to exist on Earth. Thus, it may have been a singular event, an infrequent event, or a common event, albeit one that has thus far evaded our detection outside our own planet. Herein, we will not attempt to argue for any particular frequency of life.
    [Show full text]
  • Basic Concepts of Chemical Bonding
    Basic Concepts of Chemical Bonding Cover 8.1 to 8.7 EXCEPT 1. Omit Energetics of Ionic Bond Formation Omit Born-Haber Cycle 2. Omit Dipole Moments ELEMENTS & COMPOUNDS • Why do elements react to form compounds ? • What are the forces that hold atoms together in molecules ? and ions in ionic compounds ? Electron configuration predict reactivity Element Electron configurations Mg (12e) 1S 2 2S 2 2P 6 3S 2 Reactive Mg 2+ (10e) [Ne] Stable Cl(17e) 1S 2 2S 2 2P 6 3S 2 3P 5 Reactive Cl - (18e) [Ar] Stable CHEMICAL BONDSBONDS attractive force holding atoms together Single Bond : involves an electron pair e.g. H 2 Double Bond : involves two electron pairs e.g. O 2 Triple Bond : involves three electron pairs e.g. N 2 TYPES OF CHEMICAL BONDSBONDS Ionic Polar Covalent Two Extremes Covalent The Two Extremes IONIC BOND results from the transfer of electrons from a metal to a nonmetal. COVALENT BOND results from the sharing of electrons between the atoms. Usually found between nonmetals. The POLAR COVALENT bond is In-between • the IONIC BOND [ transfer of electrons ] and • the COVALENT BOND [ shared electrons] The pair of electrons in a polar covalent bond are not shared equally . DISCRIPTION OF ELECTRONS 1. How Many Electrons ? 2. Electron Configuration 3. Orbital Diagram 4. Quantum Numbers 5. LEWISLEWIS SYMBOLSSYMBOLS LEWISLEWIS SYMBOLSSYMBOLS 1. Electrons are represented as DOTS 2. Only VALENCE electrons are used Atomic Hydrogen is H • Atomic Lithium is Li • Atomic Sodium is Na • All of Group 1 has only one dot The Octet Rule Atoms gain, lose, or share electrons until they are surrounded by 8 valence electrons (s2 p6 ) All noble gases [EXCEPT HE] have s2 p6 configuration.
    [Show full text]
  • Ocw-5.112-Lec24 the Following Content Is Provided by MIT Opencourseware Under a Creative Commons License
    MITOCW | ocw-5.112-lec24 The following content is provided by MIT OpenCourseWare under a Creative Commons license. Additional information about our license and MIT OpenCourseWare in general is available at ocw.mit.edu. Today I would like to start by discussing a timeline. And you will see in a moment what this timeline has to do with. It is obviously only a partial timeline. But let's start here in 1916, as we have done this semester, by talking about the Lewis theory of electronic structure. And his electron pair theory is something we are going to come back to a couple of times during lecture today. Let's move on to 1954. 1954 was an important year in electronic structure theory, because in that year there was awarded, to Linus Pauling, the Nobel Prize in chemistry. Let me write down Pauling here. And if you are interested in knowing something about what Pauling was awarded the Nobel Prize in chemistry for, I will show you over here on the side boards. What you are going to see here, if you read this citation for Linus Carl Pauling in 1954 for the Nobel Prize in chemistry, his prize was awarded principally for his contributions to our understanding of the nature of the chemical bond. If you think back to the elegant title of the paper by Lewis that we started out our discussion of acid-base theory with, it was a paper entitled "The Atom and the Molecule." And now we have gotten to Pauling, in 1954, who is being awarded a Nobel Prize in chemistry for the nature of the chemical bond.
    [Show full text]
  • 10: Alkenes and Alkynes. Electrophilic and Concerted Addition Reactions
    (2/94)(8,9/96)(12/03)(1,2/04) Neuman Chapter 10 10: Alkenes and Alkynes. Electrophilic and Concerted Addition Reactions Addition Reactions Electrophilic Addition of H-X or X2 to Alkenes Addition of H-X and X2 to Alkynes Alkenes to Alcohols by Electrophilic Addition Alkenes to Alcohols by Hydroboration Addition of H2 to Alkenes and Alkynes Preview (To be added) 10.1 Addition Reactions We learned about elimination reactions that form C=C and Cº C bonds in Chapter 9. In this chapter we learn about reactions in which reagents add to these multiple bonds. General Considerations (10.1A) We show a general equation for an addition reaction with an alkene in Figure 10.01. Figure 10.01 (see Figure folder for complete figure) A¾ B A B | | C=C ® C¾ C This equation is the reverse of the general equation for an elimination reaction that we showed at the beginning of Chapter 9. This general equation does not show a mechanism for the addition process. There are a number of different types of mechanisms for addition reactions, but we can group them into the four broad categories of (1) electrophilic addition, (2) nucleophilic addition, (3) free radical addition, and (4) concerted addition. Electrophilic and nucleophilic addition reactions involve intermediate ions so they are ionic addition reactions. In contrast, free radical additions, and 1 (2/94)(8,9/96)(12/03)(1,2/04) Neuman Chapter 10 concerted addition reactions, are non-ionic addition reactions because they do not involve the formation of intermediate ions. Ionic Addition Reactions (10.1B) We compare general features of nucleophilic and electrophilic addition reactions here.
    [Show full text]
  • Organic and Biological Chemistry
    CHAPTER 23 Organic and Biological Chemistry CONTENTS HO H 23.1 ▶ Organic Molecules and Their C Structures: Alkanes H H C 23.2 ▶ Families of Organic Compounds: HO O O C C Functional Groups 23.3 ▶ Naming Organic Compounds H CC 23.4 ▶ Carbohydrates:HO A Biological Example HO OH of Isomers H 23.5 ▶ Valence Bond TCheory and Orbital OverlapH Pictures H C 23.6 ▶ Lipids:HO A Biological EOxample ofO Cis–Trans IsomerismC C 23.7 ▶ Formal Charge and Resonance in Organic CompoundsH CC 23.8 ▶ Conjugated SystemsHO OH 23.9 ▶ Proteins: A Biological Example of Conjugation 23.10 ▶ Aromatic Compounds and Molecular Ascorbic acid, also known as vitamin C, is an essential nutrient in the human diet Orbital Theory because it is not synthesized in our body. We can eat citrus fruits or take pills that contain vitamin C to maintain health. 23.11 ▶ Nucleic Acids: A Biological Example of Aromaticity ? Which Is Better, Natural or Synthetic? The answer to this question can be found in the INQUIRY ▶▶▶ on page 1021. STUDY GUIDE M23_MCMU3170_07_SE_C23.indd 978 27/11/14 2:11 AM f the ultimate goal of chemistry is to understand the world around us on a molecular level, then a knowledge of biochemistry—the chemistry of living organisms—is a central part Iof that goal. Biochemistry, in turn, is a branch of organic chemistry, a term originally used to mean the study of compounds from living organisms while inorganic chemistry was used for the study of compounds from nonliving sources. Today, however, we know that there are no fundamental differences between organic and inorganic compounds; the same principles apply to both.
    [Show full text]
  • 1: Organic Molecules and Chemical Bonding
    (4,5,9,11,12/98)(1,9,10/99) Neuman Chapter 1 1: Organic Molecules and Chemical Bonding Organic Molecules Chemical Bonds Organic Chemistry Bon voyage Preview Organic chemistry describes the structures, properties, preparation, and reactions of a vast array of molecules that we call organic compounds. There are many different types of organic compounds, but all have carbon as their principal constituent atom. These carbon atoms form a carbon skeleton or carbon backbone that has other bonded atoms such as H, N, O, S, and the halogens (F, Cl, Br, and I). We frequently hear the term "organic" in everyday language where it describes or refers to substances that are "natural". This is probably a result of the notion of early scientists that all organic compounds came from living systems and possessed a "vital force". However, chemists learned over 170 years ago that this is not the case. Organic compounds are major components of living systems, but chemists can make many of them in the laboratory from substances that have no direct connection with living systems. Chemically speaking, a pure sample of an organic compound such as Vitamin C prepared in a laboratory is chemically identical to a pure sample of Vitamin C isolated from a natural source such as an orange or other citrus fruit. Your journey through organic chemistry will be challenging because of the large amount of information that you will need to learn and understand. However, we will explore this subject in a systematic manner so that it is not a vast collection of isolated facts.
    [Show full text]
  • Chemical Bonding and Molecular Structure
    100 CHEMISTRY UNIT 4 CHEMICAL BONDING AND MOLECULAR STRUCTURE Scientists are constantly discovering new compounds, orderly arranging the facts about them, trying to explain with the existing knowledge, organising to modify the earlier views or After studying this Unit, you will be evolve theories for explaining the newly observed facts. able to • understand KÖssel-Lewis approach to chemical bonding; • explain the octet rule and its Matter is made up of one or different type of elements. limitations, draw Lewis Under normal conditions no other element exists as an structures of simple molecules; independent atom in nature, except noble gases. However, • explain the formation of different a group of atoms is found to exist together as one species types of bonds; having characteristic properties. Such a group of atoms is • describe the VSEPR theory and called a molecule. Obviously there must be some force predict the geometry of simple which holds these constituent atoms together in the molecules; molecules. The attractive force which holds various • explain the valence bond constituents (atoms, ions, etc.) together in different approach for the formation of chemical species is called a chemical bond. Since the covalent bonds; formation of chemical compounds takes place as a result • predict the directional properties of combination of atoms of various elements in different of covalent bonds; ways, it raises many questions. Why do atoms combine? Why are only certain combinations possible? Why do some • explain the different types of hybridisation involving s, p and atoms combine while certain others do not? Why do d orbitals and draw shapes of molecules possess definite shapes? To answer such simple covalent molecules; questions different theories and concepts have been put forward from time to time.
    [Show full text]
  • The Mystery of Life's Origin
    The Mystery of Life’s Origin The Continuing Controversy CHARLES B. THAXTON, WALTER L. BRADLEY, ROGER L. OLSEN, JAMES TOUR, STEPHEN MEYER, JONATHAN WELLS, GUILLERMO GONZALEZ, BRIAN MILLER, DAVID KLINGHOFFER Seattle Discovery Institute Press Description e origin of life from non-life remains one of the most enduring mysteries of modern science. e Mystery of Life’s Origin: e Continuing Controversy investigates how close scientists are to solving that mystery and explores what we are learning about the origin of life from current research in chemistry, physics, astrobiology, biochemistry, and more. e book includes an updated version of the classic text e Mystery of Life’s Origin by Charles axton, Walter Bradley, and Roger Olsen, and new chapters on the current state of the debate by chemist James Tour, physicist Brian Miller, astronomer Guillermo Gonzalez, biologist Jonathan Wells, and philosopher of science Stephen C. Meyer. Copyright Notice Copyright © 2020 by Discovery Institute, All Rights Reserved. Library Cataloging Data e Mystery of Life’s Origin: e Continuing Controversy by Charles B. axton, Walter L. Bradley, Roger L, Olsen, James Tour, Stephen Meyer, Jonathan Wells, Guillermo Gonzalez, Brian Miller, and David Klinghoffer 486 pages, 6 x 9 x 1.0 inches & 1.4 lb, 229 x 152 x 25 mm. & 0.65 kg Library of Congress Control Number: 9781936599745 ISBN-13: 978-1-936599-74-5 (paperback), 978-1-936599-75-2 (Kindle), 978-1-936599-76-9 (EPUB) BISAC: SCI013040 SCIENCE / Chemistry / Organic BISAC: SCI013030 SCIENCE / Chemistry / Inorganic BISAC: SCI007000 SCIENCE / Life Sciences / Biochemistry BISAC: SCI075000 SCIENCE / Philosophy & Social Aspects Publisher Information Discovery Institute Press, 208 Columbia Street, Seattle, WA 98104 Internet: http://www.discoveryinstitutepress.com/ Published in the United States of America on acid-free paper.
    [Show full text]
  • Chemical Bonding
    CHEMICAL BONDING 1 18 1A 8A 1 2 13 14 15 16 17 2A 3A 4A 5A 6A 7A 2 1+ 2+ 3- 2- 1- 3 1+ 2+ 2- 1- 3 4 5 6 7 8 9 10 11 12 4 1+ 2+ 3+ 4+ 5+ 3+ 2+ 3+ 2+ 2+ 2+ 2+ 3+ 2- 1- 5 1+ 2+ 3+ 4+ 5+ 2- 1- 6 1+ 2+ 3+ 7 2+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ Neutral Atom Positive Ion by Negative Ion DR. STEPHEN THOMPSON MR. JOE STALEY The contents of this module were developed under grant award # P116B-001338 from the Fund for the Improve- ment of Postsecondary Education (FIPSE), United States Department of Education. However, those contents do not necessarily represent the policy of FIPSE and the Department of Education, and you should not assume endorsement by the Federal government. CHEMICAL BONDING CONTENTS 2 Electronegativity 3 Road Map 4 Types Of Bonding 5 Properties Controlled By Chemical Bond 6 Polar Bonds 7 Metallic Bonding 8 Intermolecular Forces 9 Ions: Counting Electrons And Protons 10 Ionic And Atomic Radii 11 Ions And Energy 12 Lithium Fluoride 13 Crystal Packing 14 Crystal Packing 15 Crystal Packing 16 Covalent H2 17 Quantization 18 Bond Length And Strength 19 Strong And Weak Bonds 20 Strong And Weak Bonds 21 Covalent To Metallic 22 Electron Delocalization CHEMICAL BONDING ELECTRONEGATIVITY Hydrogen 1 Metals 18 Electronegativity 1A Metalloids 8A 2.1 2 Nonmetals 13 14 15 16 17 0 H 2A 3A 4A 5A 6A 7A He Group 18 0.98 1.57 2.04 2.55 3.04 3.44 3.98 0 Li Be B C N O F Ne 0.93 1.31 1.61 1.9 2.19 2.58 3.16 0 Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S Cl Ar 0.82 1 1.36 1.54 1.63 1.66 1.55 1.83 1.88 1.91
    [Show full text]
  • Chemical Bonding: the Journey from Miniature Hooks to Density Functional Theory
    molecules Review Chemical Bonding: The Journey from Miniature Hooks to Density Functional Theory Edwin C. Constable * and Catherine E. Housecroft Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland; [email protected] * Correspondence: [email protected]; Tel.: +41-61-207-1001 Academic Editor: Antonio J. Mota Received: 10 May 2020; Accepted: 3 June 2020; Published: 5 June 2020 Abstract: Our modern understanding of chemistry is predicated upon bonding interactions between atoms and ions resulting in the assembly of all of the forms of matter that we encounter in our daily life. It was not always so. This review article traces the development of our understanding of bonding from prehistory, through the debates in the 19th century C.E. bearing on valence, to modern quantum chemical models and beyond. Keywords: bonding; valency; affinity, structure; history of science 1. Introduction Bonding is what separates chemistry from physics. If the understanding of atoms and their component particles belongs primarily to the realm of physics, then chemistry is concerned with the aggregation of atoms into chemical entities held together by bonds. If science is a language, and atoms are the letters, bonding is the mechanism by which the letters are combined into words. The International Union of Pure and Applied Chemistry (IUPAC) states that “there is a chemical bond between two atoms or groups of atoms in the case that the forces acting between them are such as to lead to the formation of an aggregate with sufficient stability to make it convenient for the chemist to consider it as an independent ‘molecular species’” [1].
    [Show full text]
  • Chapter 1 Organic Molecules and Chemical Bonding
    (4,5,9,11,12/98)(1,9,10/99) Neuman Chapter 1 Chapter 1 Organic Molecules and Chemical Bonding from Organic Chemistry by Robert C. Neuman, Jr. Professor of Chemistry, emeritus University of California, Riverside [email protected] <http://web.chem.ucsb.edu/~neuman/orgchembyneuman/> Chapter Outline of the Book ************************************************************************************** I. Foundations 1. Organic Molecules and Chemical Bonding 2. Alkanes and Cycloalkanes 3. Haloalkanes, Alcohols, Ethers, and Amines 4. Stereochemistry 5. Organic Spectrometry II. Reactions, Mechanisms, Multiple Bonds 6. Organic Reactions *(Not yet Posted) 7. Reactions of Haloalkanes, Alcohols, and Amines. Nucleophilic Substitution 8. Alkenes and Alkynes 9. Formation of Alkenes and Alkynes. Elimination Reactions 10. Alkenes and Alkynes. Addition Reactions 11. Free Radical Addition and Substitution Reactions III. Conjugation, Electronic Effects, Carbonyl Groups 12. Conjugated and Aromatic Molecules 13. Carbonyl Compounds. Ketones, Aldehydes, and Carboxylic Acids 14. Substituent Effects 15. Carbonyl Compounds. Esters, Amides, and Related Molecules IV. Carbonyl and Pericyclic Reactions and Mechanisms 16. Carbonyl Compounds. Addition and Substitution Reactions 17. Oxidation and Reduction Reactions 18. Reactions of Enolate Ions and Enols 19. Cyclization and Pericyclic Reactions *(Not yet Posted) V. Bioorganic Compounds 20. Carbohydrates 21. Lipids 22. Peptides, Proteins, and α−Amino Acids 23. Nucleic Acids **************************************************************************************
    [Show full text]
  • Meyer, Stephen C
    DNA BY DESIGN: AN INFERENCE TO THE BEST EXPLANATION FOR THE ORIGIN OF BIOLOGICAL INFORMATION STEPHEN C. MEYER INTRODUCTION n the second chapter of Philosophy and Biology,Elliott Sober warns historians I and philosophers of biology against the danger of anachronism. In particular, he notes that many contemporary evolutionary biologists regard the design hypothe- sis as inherently untestable and, therefore, unscientific in principle, simply because it no longer commands scientific assent. He notes that while logically unbeatable versions of the design hypothesis have been formulated (involving, for example, a “trickster God” who creates a world that appears undesigned), design hypotheses in general need not assume an untestable character. A design hypothesis could, he argues, be formulated as a fully scientific “inference to the best explanation.” He notes that scientists often evaluate the explanatory power of a “hypothesis by test- ing it against one or more competing hypotheses.”1 On these grounds, he notes that William Paley’s version of the design hypothesis was manifestly testable, but was rejected precisely because it could not explain the relevant evidence of then con- temporary biology as well as the fully naturalistic theory of Charles Darwin. Sober then casts his lot with the neo-Darwinian explanation on evidential rather than methodological grounds. But the possibility remains, he argues, that there is some other version of the design hypothesis that both disagrees with the hypothesis of evolution and also is a more likely explanation of what we observe. No one, to my knowledge, has developed such a version of the design hypothesis. But this does not mean that no one ever will.2 This paper will develop a design hypothesis, not as an explanation for the origin of species, but as an explanation for the origin of the information required to make a living system in the first place.
    [Show full text]