Origin of Atomic Theory as Viewed by the European Scientists
|
|
- Cecil Harrell
- 5 years ago
- Views:
Transcription
1 The Greening of Petroleum Operations by M.R. Islam, A.B. Chhetri and M.M. Khan Copyright 2010 Scrivener Publishing LLC. Appendix 1 Origin of Atomic Theory as Viewed by the European Scientists From website: Chemistry encyclopedia at chemistryexplained.com/ar-bo/atoms.html, accessed October 24, 2008 Atoms An atom is the smallest possible unit of an element. Since all forms of matter consist of a combination of one or more elements, atoms are the building blocks that constitute all the matter in the universe. Currently, 110 different elements, and thus 110 different kinds of atoms, are known to exist. Our current understanding of the nature of atoms has evolved from the ancient, untested ideas of Greek philosophers, partly as a result of modern technology that has produced images of atoms. The Greek Atomistic Philosophy The earliest ideas concerning atoms can be traced to the Greek philosophers, who pursued wisdom, knowledge, and truth through argument and reason. Greek scientific theories were largely based 775
2 776 APPENDIX I on speculation, sometimes based on observations of natural phenomena and sometimes not. The idea of designing and performing experiments rarely occurred to Greek philosophers, to whom abstract intellectual activity was the only worthy pastime. Empedocles, a Greek philosopher active around 450 B.C., proposed that there were four fundamental substances earth, air, fire, and water which, in various proportions, constituted all matter. Empedocles, thus, formulated the idea of an elemental substance, a substance that is the ultimate constituent of matter; the chemical elements are modern science's fundamental substances. An atomic theory of matter was proposed by Leucippus, another Greek philosopher, around 478 B.C. Our knowledge of the atomic theory of Leucippus is derived almost entirely from the writings of his student, Democritus, who lived around 420 B.C. Democritus maintained that all materials in the world were composed of atoms (from the Greek atomos, meaning indivisible). According to Democritus, atoms of different shapes, arranged and positioned differently relative to each other, accounted for the different materials of the world. Atoms were supposed to be in random perpetual motion in a void; that is, in nothingness. According to Democritus, the feel and taste of a substance was thought to be the effect of the atoms of the substance on the atoms of our sense organs. The atomic theory of Democritus provided the basis for an explanation of the changes that occur when matter is chemically transformed. Unfortunately, the theory was rejected by Aristotle ( B.C.) who became the most powerful and famous of the Greek scientific philosophers. However, Aristotle adopted and developed Empedocles's ideas of elemental substances. Aristotle's elemental ideas are summarized in a diagram (shown in Figure 1), which associated the four elemental substances with four qualities: hot, moist, cold, and dry. Earth was dry and cold; water was cold and moist; air was moist and hot; and fire was hot and dry. Every substance was composed of combinations of the four elements, and changes (which we now call chemical) were explained by an alteration in the proportions of the four elements. One element could be converted into the other by the addition or removal of the appropriate qualities. There were, essentially, no attempts to produce evidence to support this fourelement theory, and, since Aristotle's scientific philosophy held sway for 2,000 years, there was no progress in the development of the atomic concept. The tenuous relationship between elements and atoms had been severed when Aristotle rejected the ideas of
3 APPENDIX I 777 Fire Air Earth Moist Water Figure 1 Aristotle's four-element diagram. Democritus. Had the Greek philosophers been open to the idea of experimentation, atomic theory, indeed all of science, could have progressed more rapidly. The Rise of Experimentation The basis of modern science began to emerge in the seventeenth century, which is often recognized as the beginning of the Scientific Revolution. Conceptually, the Scientific Revolution can be thought of as a battle between three different ways of looking at the natural world: the Aristotelian, the magical, and the mechanical. The seventeenth century saw the rise of experimental science. The idea of making observations was not new. However, Sir Francis Bacon ( ) emphasized that experiments should be planned and the results carefully recorded so they could be repeated and verified, an attitude that infuses the core idea of modern science. Among the early experimentalists was Robert Boyle ( ), who studied quantitatively the compression and expansion of air, which led him to the idea that air was composed of particles that he called corpuscles, which he maintained were in constant motion. Boyle's description of corpuscular motion presages the kinetic molecular theory. The Chemical Atom An atomic theory based on chemical concepts began to emerge from the work of Antoine Lavoisier ( ), whose careful
4 778 APPENDIX I quantitative experiments led to an operational definition of an element: An element was a substance that could not be decomposed by chemical processes. In other words, if a chemist could not decompose a substance, it must be an element. This point of view obviously put a premium on the ability of chemists to manipulate substances. Inspection of Lavoisier's list of elements, published in 1789, shows a number of substances, such as silica (Si0 2 ), alumina (A ), and baryta (BaO), which today are recognized as very stable compounds. The chemists of Lavoisier's time simply did not have the tools to decompose these substances further to silicon, aluminum, and barium, respectively. The composition of all compounds could be expressed in terms of the elemental substances, but it was the quantitative mass relationship of compounds that was the key to deducing the reality of the chemical atom. Lavoisier's successful use of precise mass measurements essentially launched the field of analytical chemistry, which was thoroughly developed by Martin Klaproth ( ). Lavoisier established the concept of mass conservation in chemical reactions, and, late in the eighteenth century, there was a general acceptance of the concept of definite proportions (constant composition) in chemical compounds, but not without controversy. Claude-Louis Berthollet ( ) maintained that the composition of compounds could be variable, citing, for example, analytical results on the oxides of copper, which gave a variety of results, depending on the method of synthesis. Joseph-Louis Proust ( ), over a period of eight years, showed that the variable compositions, even with very accurate analytical data, were due to the formation of different mixtures of two oxides of copper, CuO and Cu 2 0. Each oxide obeyed the law of constant composition, but reactions that were supposed to lead to "copper oxide" often produced mixtures, the proportions of which depended on the conditions of the reaction. Proust's proof of the law of constant composition was important, because compounds with variable composition could not be accommodated within the evolving chemical atomic theory. Democritus Of Abbera Little is known for certain about Democritus of Abbera (c.460 B.C.E.-C.362 B.C.E.). None of his writings has survived intact. It is known from others (both students and detractors) that
5 APPENDIX I 779 Democritus was one of the earliest advocates of a theory that all matter exists as collections of very small, permanent, indivisible particle called atoms. David A. Bassett John Dalton ( ), a self-educated English scientist, was primarily interested in meteorology and is credited with being the first to describe color blindness, a condition with which he was burdened throughout his life. Color blindness is a disadvantage for a chemist, who must be able to see color changes when working with chemicals. Some have suggested that his affliction was one reason why Dalton was a rather clumsy and slip-shod experimenter. Gaseous behavior had been well established, starting with the experiments of Boyle. Dalton could not help supposing, as others previously did, that gaseous matter was composed of particles. But Dalton took the next and, ultimately, most important steps in assuming that all matter gaseous, liquid, and solid consists of these small particles. The law of definite proportions (constant composition) as articulated by Proust, suggested to Dalton that a compound might contain two elements in the ratio of, for example, 4 to 1, but never 4.1 to 1 or 3.9 to 1. This observation could easily be explained by supposing that each element was made up of individual particles. Dalton's atomic theory can be succinctly summarized by the following statements: Elements are composed of extremely small particles called atoms. All atoms of a given element have identical properties, and those properties differ from those of other elements. Compounds are formed when atoms of different elements combine with one another in small whole numbers. The relative numbers and kinds of atoms are constant in a given compound. Dalton recognized the similarity of his theory to that of Democritus, advanced twenty-one centuries earlier when the Greek philosopher called these small particles atoms, and, presumably, implied by using that word that these particles were indivisible. In Dalton's representation (Figure 2) the elements were shown as small spheres, each with a separate identity. Compounds of elements were shown by combining the appropriate elemental representations in the correct proportions, to produce complex symbols that seem to echo
6 780 APPENDIX I Figure 2 Dalton's atomic symbols are described as "simple." The increasingly complex combination of symbols represent binary, ternary, quaternary, etc., compounds. Thus, Number 28 is a compound atom of carbonic acid (carbon dioxide), and number 31 is a compound atom of sulphuric acid (sulphyr trioxide). our present use of standard chemical formulas. Dalton's symbols circles with increasingly complex inserts and decorations were not adopted by the chemical community. Current chemical symbols (formulas) are derived from the suggestions of Jons Berzelius ( ). Berzelius also chose oxygen to be the standard reference for atomic mass (O = AMU). Berzelius produced a list of atomic masses that were much closer to those that are currently accepted because he had developed a better way to obtain the formulas of substances. Whereas Dalton assumed that water had the formula HO, Berzelius showed it to be H 2 0. The property of atoms of interest to Dalton were their relative masses, and Dalton produced a table
7 Table 1 Dalton's first set of atomic weight values (1805). APPENDIX I 781 Hydrogen Azot Carbon Ammonia Oxygen Water Phosphorus Phosphuretted hydrogen Nitrous gas Ether Gaseous oxide of carbon Nitrous oxide Sulphur Nitric acid Sulphuretted hydrogen Carbonic acid Alcohol Sulphureous acid Sulphuric acid Carburetted hydrogen from stagnant water Olefiant gas of atomic masses (Table 1) that was seriously deficient because he did not appreciate that atoms did not have to be in a one-to-one ratio; using more modern ideas, Dalton assumed, incorrectly, that all atoms had a valence of one (1). Thus, if the atomic mass of hydrogen is arbitrarily assigned to be 1, the atomic mass of oxygen is 8 on the Dalton scale. Dalton, of course, was wrong, because a water molecule contains two atoms of hydrogen for every oxygen atom, so that the individual oxygen atom is eight times as heavy as two hydrogen atoms or sixteen times as heavy as a single hydrogen atom. There was no way that Dalton could have known, from the data available, that the formula for water is H 2 0.
8 782 APPENDIX I Dalton's atomic theory explained the law of multiple proportions. For example, it is known that mercury forms two oxides: a black substance containing 3.8 percent oxygen and 96.2 percent mercury, and a red compound containing 7.4 percent oxygen and 92.6 percent mercury. Dalton's theory states that the atoms of mercury (Hg) and oxygen (O) must combine in whole numbers, so the two compounds might be HgO and Hg z O, for example. Furthermore, Dalton's theory states that each element has a characteristic mass perhaps 9 mass units for Hg and 4 mass units for O (the numbers were chosen arbitrarily, here). Given these assumptions, the relevant concepts are shown in Table 2. The assumed formulas are presented in line 1. The percent composition of each compound, calculated in the usual way, is presented in line 3, showing that these two compounds, indeed, have different compositions, as required by the law of multiple proportions. Line 4 contains the ratio of the mass of mercury to the mass of oxygen, for each compound. Those ratios can be expressed as the ratio of simple whole numbers (2.25:4.5 = 1:2), fulfilling a condition required by the law of multiple proportions. Notice that Dalton's ideas do not depend upon the values assigned to the elements or the formulas for the compounds involved. Indeed, the question as to which compound, red or black, is associated with which formula cannot be answered from the data available. Thus, although Dalton was unable to establish an atomic mass scale, his general theory did provide an understanding of the three mass-related laws: conservation, constant composition, and multiple proportion. Other information was required to establish the relative masses of atoms. The other piece of the puzzle of relative atomic masses was provided by Joseph-Louis Gay-Lussac ( ), who published a paper on volume relationships in reactions of gases. Gay-Lussac made no attempt to interpret his results, and Dalton questioned the paper's validity, not realizing that the law of combining volumes Table 2 Law of multi Die proportions. Assumed formula Total mass of compound % composition Mass Hg/Mass O HgO = 13 % Hg 69.2; % O = /4 = 2.25 H&O = 22 % Hg = 81.8; %0= /4 = 4.5
9 APPENDIX I 783 was really a verification of his atomic theory! Gay-Lussac's experiments revealed, for example, that 2 volumes of carbon monoxide combine with 1 volume of oxygen to form 2 volumes of carbon dioxide. Reactions of other gaseous substances showed similar volume relationships. Gay-Lussac's law of combining volumes suggested, clearly, that equal volumes of different gases under similar conditions of temperature and pressure contain the same number of reactive particles (molecules). Thus, if 1 volume of ammonia gas (NH 3 ) combines exactly with 1 volume of hydrogen chloride gas (HC1) to form a salt (NH 4 C1), it is natural to conclude that each volume of gas must contain the same number of particles. At least one of the implications of Gay-Lussac's law was troubling to the chemistry community. For example, in the formation of water, 2 volumes of hydrogen gas combined with 1 volume of oxygen gas to produce 2 volumes of steam (water in the gaseous state). These observations produced, at the time, an apparent puzzle. If each volume of gas contains n particles (molecules), 2 volumes of steam must contain 2 n particles. Now, if each water particle contains at least 1 oxygen atom, how is it possible to get two oxygen atoms (corresponding to 2 n water molecules) from n oxygen particles? The obvious answer to this question is that each oxygen particle contains two oxygen atoms. This is equivalent to stating that the oxygen molecule consists of two oxygen atoms, or that oxygen gas is diatomic (0 2 ). Amedeo Avogadro ( ) an Italian physicist, resolved the problem by adopting the hypothesis that equal volumes of gases under the same conditions contain equal numbers of particles (molecules). His terminology for what we now call an atom of, for instance, oxygen, was half molecule. Similar reasoning involving the combining of volumes of hydrogen and oxygen to form steam leads to the conclusion that hydrogen gas is also diatomic (H 2 ). Despite the soundness of Avogadro's reasoning, his hypothesis was generally rejected or ignored. Dalton never appreciated its significance because he refused to accept the experimental validity of Gay-Lussac's law. Avogadro's hypothesis equal volumes of gases contain equal numbers of particles lay dormant for nearly a half-century, until 1860 when a general meeting of chemists assembled in Karlsruhe, Germany, to address conceptual problems associated with determining the atomic masses of the elements. Two years earlier, Stanislao Cannizzaro ( ) had published a paper in which, using Avogadro's hypothesis and vapor density data, he was able
10 784 APPENDIX I to establish a scale of relative atomic masses of the elements. The paper, when it was published, was generally ignored, but its contents became the focal point of the Karlsruhe Conference. Cannizzaro's argument can be easily demonstrated using the compounds hydrogen chloride, water, ammonia, and methane, and the element hydrogen, which had been shown to be diatomic (H 2 ) by using Gay-Lussac's reasoning and his law of combining volumes. The experimental values for vapor density of these substances, all determined under the same conditions of temperature and pressure, are also required for Cannizzaro's method for establishing atomic masses. The relevant information is gathered in Table 3. The densities of these gaseous substances (at 100 C and one atmosphere pressure) are expressed in grams per liter. The masses of the substances (in one liter) are the masses of equal numbers of molecules of each substance; the specific number of molecules is unknown, of course, but that number is unnecessary for the Cannizzaro analysis. If that unknown number of molecules is called N, and if m H represents the mass of a single hydrogen atom, then m H x 2N is the total mass of the hydrogen atoms in the 1 liter sample of hydrogen molecules; recall that hydrogen was shown to be diatomic (H 2 ) by Gay-Lussac's law. From this point of view, the relative masses of the molecules fall in the order of the masses in 1 liter (or their densities). The mass of the hydrogen atom was taken as the reference (H = 1) for the relative atomic masses of the elements. Thus, the mass of all the hydrogen chloride molecules in the one liter sample is m QN, and the ratio of the mass of a hydrogen chloride molecule to a hydrogen atom is given by: Table 3 Cannizzaro's method of molecular mass determination. Gaseous Substance Hydrogen Hydrogen chloride Water Ammonia Methane Density g/l' Relative to Mass of an H Atom (Molecular Mass, Relative to H = l) % Hydrogen Relative Mass ofh Present Number H Atoms Present in a Molecule Formula H 2 HC1 H 2 0 NH, CH 4 Mass of "Other" Atoms H = l Cl = = N = C = 'Density reported for conditions of 100 C and one atmosphere pressure
11 APPENDIX I 785 That is, if the mass of a hydrogen atom is taken to be 1 unit of mass, the mass of the hydrogen chloride molecule is units. All the molecular masses listed in column 3 of the table can be established in the same way twice the ratio of the density of the molecule in question to the density of hydrogen. Using experimental analytical data (column 4), Cannizzaro was able to establish the relative mass of hydrogen in each molecule (column 5), which gave the number of hydrogen atoms present in each molecule of interest (column 6), which, in turn, produced the formula of the molecule (column 7); analytical data also quantitatively indicate the identity of the other atom in the molecule. Thus, analysis would tell us that, for example, methane contains hydrogen and carbon. Knowing the total mass of the molecule (column 3) and the mass of all the hydrogen atoms present, the mass of the "other atom" in the molecule can be established as the difference between these numbers (column 8). Thus, if the mass of the HCl molecule is and one atom of hydrogen of mass 1.00 is present, the mass of a Cl atom is Relative mass units are called atomic mass units, AMUs. This very convincing use of Gay-Lussac's law and Avogadro's hypothesis by Cannizzaro quickly provided the chemical community with a direct way of establishing not only the molecular formulas of binary compounds but also the relative atomic masses of elements, starting with quantitative analytical data and the density of the appropriate gaseous substances. The long struggle to establish the concept of the chemical atom involved many scientists working in different countries using different kinds of equipment to obtain self-consistent data. All were infused with ideas of Sir Francis Bacon, who defined the classic paradigm of experimental science results that are derived from careful observations and that are openly reported for verification. However, not all chemists equally embraced these ideas, which were to become fundamental to their craft. For example, the great physical chemist and Nobel Prize winner Friedrich Wilhelm Ostwald ( ) refused to accept the existence of atoms well into the twentieth century. Ostwald held a strong personal belief that chemists ought to confine their studies to measurable phenomena such as energy changes. The atomic theory was to Ostwald nothing more than a convenient fiction. There are, of course, other lines of observations and arguments that lead to the conclusion that matter is particulate and, subsequently, to an ultimate atomic description of matter. One of these
12 786 APPENDIX I involves the Brownian motion of very small particles. Robert Brown ( ), a Scottish botanist, observed in 1827 that individual grains of plant pollen suspended in water moved erratically. This irregular movement of individual particles of a suspension as observed with a microscope is called Brownian motion. Initially, Brown believed that this motion was caused by the "hidden life" within the pollen grains, but further studies showed that even nonliving suspensions behave in the same way. In 1905 Albert Einstein ( ) worked out a mathematical analysis of Brownian motion. Einstein showed that if the water in which the particles were suspended was composed of molecules in random motion according to the requirements of the kinetic molecular theory, then the suspended particles would exhibit a random "jiggling motion" arising from the occasional uneven transfer of momentum as a result of water molecules striking the pollen grains. One might expect that the forces of the water molecules striking the pollen grains from all directions would average out to a zero net force. But Einstein showed that, occasionally, more water molecules would strike one side of a pollen grain than the other side, resulting in a movement of the pollen grain. The interesting point in Einstein's analysis is that even if each collision between a water molecule and a pollen grain transfers a minuscule amount of momentum, Photomicrograph of atoms in a tungsten crystal, magnified 2,700,000 times.
13 APPENDIX I 787 the enormous number of molecules striking the pollen grain is sufficient to overcome the large momentum advantage of the pollen grain (because of its considerably larger mass than that of a water molecule). Although the Swedish chemist Theodor Svedberg ( ) suggested the general molecular explanation earlier, it was Einstein who worked out the mathematical details. Einstein's analysis of Brownian motion was partially dependent on the size of the water molecules. Three years later, Jean-Baptiste Perrin ( ) set about to determine the size of the water molecules from precise experimental observations of Brownian motion. In other words, Perrin assumed Einstein's equations were correct, and he made measurements of the particles' motions, which Brown had described only qualitatively. The data Perrin collected allowed him to calculate the size of water molecules. Ostwald finally yielded in his objection to the existence of atoms because Perrin had a direct measure of the effect of water molecules on macroscopic objects (pollen grains). Since water was composed of the elements hydrogen and oxygen, the reality of atoms had been experimentally proved in Ostwald's view of how chemistry should be pursued. Ostwald's reluctance to accept the chemical atom as an entity would surely have yielded to the overwhelming evidence provided by scanning tunneling microscopy (STM). Although Ostwald did not live to see it, this technique provides such clear evidence of the reality of simple atoms that even he would have been convinced. SEE ALSO Avogadro, Amedeo; Berthollet, Claude-Louis; Berzelius, Jons JaKob; Boyle, Robert; Cannizzaro, Stanislao; Dalton, John; Einstein, Albert; Gay-Lussac, Joseph-Louis; Lavoisier, Antoine; Ostwald, Friedrich Wilhelm; Svedberg, Theodor; MOLDCULES. /. /. Lagowski Bibliography Hartley, Harold (1971). Studies in the History of Chemistry. Oxford, U.K.: Clarendon Press. Ihde, Aaron J. (1964). The Development of Modem Chemistry. New York: Harper and Row. Lavoisier, Antoine; Fourier, Jean-Baptiste Joseph; and Faraday, Michael (1952). Great Books of the Western World, Vol. 45, tr. Robert Kerr and Alexander Freeman. Chicago: Encyclopedia Britannica.
What Do You Think? Investigate GOALS
Activity 3 Atoms and Their Masses GOALS In this activity you will: Explore the idea of atoms by trying to isolate a single atom. Measure how many times greater the mass of a copper atom is than a magnesium
More informationGas Volumes and the Ideal Gas Law
Section 3, 9B s Gases react in whole-number ratios. Equal volumes of gases under the same conditions contain equal numbers of molecules. All gases have a volume of 22.4 L under standard conditions. In
More informationLaw of conservation of mass If a piece of magnesium is burnt, will there be a gain or a loss in mass? Why?
1 Atomic Theory Law of conservation of mass If a piece of magnesium is burnt, will there be a gain or a loss in mass? Why? Activity Measure the mass of 500 cm 3 of your favorite drink. Then compare your
More informationChemistry for Changing Times, 13e (Hill) Chapter 2 Atoms. 2.1 Multiple Choice Questions
Chemistry for Changing Times 13th Edition Hill Test Bank Full Download: http://testbanklive.com/download/chemistry-for-changing-times-13th-edition-hill-test-bank/ Chemistry for Changing Times, 13e (Hill)
More informationCHAPTER 3. Atoms: The Building Blocks of Matter
CHAPTER 3 Atoms: The Building Blocks of Matter Origins of the Atom Democritus: Greek philosopher (460 BC - 370 BC) Coined the term atom from the Greek word atomos Democritus believes that atoms were indivisible
More informationGas Volumes and the Ideal Gas Law
SECTION 11.3 Gas Volumes and the Ideal Gas Law Section 2 presented laws that describe the relationship between the pressure, temperature, and volume of a gas. The volume of a gas is also related to the
More informationCHAPTER 1 The Birth of Modern Physics
CHAPTER 1 The Birth of Modern Physics 1.1 Classical Physics of the 1890s 1.2 The Kinetic Theory of Gases 1.3 Waves and Particles 1.4 Conservation Laws and Fundamental Forces 1.5 The Atomic Theory of Matter
More informationHISTORY OF CHEMISTRY BY SARA C. MIGUEL M. JESSICA S.
HISTORY OF CHEMISTRY BY SARA C. MIGUEL M. JESSICA S. A Little Info! Chemistry is a branch of science Dates back to prehistoric times ( looong time ago ) Is separated into four different time periods Prehistoric
More information1.02 Scientific Method
1.02 Scientific Method Dr. Fred O. Garces Chemistry 100 Miramar College 1 Science and the meaning of life Ever since humans had the ability to think and reason, they have been trying to answer some basic
More informationCHAPTER - 3 Atoms and Molecules
CHAPTER - 3 Atoms and Molecules CONCEPT DETAILS KEY CONCEPTS : [ *rating as per the significance of concept] 1. Laws of Chemical Combination *** 2. John Daltons Atomic Theory ** 3. Atoms, ions & Chemical
More informationChemistry. Chemistry is. The Study of Matter Change Study Study of the Composition of Substances & the Changes They Undergo. Matter: Mass: Volume:
Chemistry 9/4/2005 Chemistry: Chapters 1 & 2 1 Chemistry is The Study of Matter Change Study Study of the Composition of Substances & the Changes They Undergo 9/4/2005 Chemistry: Chapters 1 & 2 2 Matter:
More informationChapter 7 Notes. Matter is made of tiny particles in constant motion
Chapter 7 Notes Section 7.1 Matter is made of tiny particles in constant motion Atomic Theory Greek philosophers (430 BC ) Democritus and Leucippus proposed that matter is made of tiny particles called
More informationAtomic Masses and Molecular Formulas *
OpenStax-CNX module: m44278 1 Atomic Masses and Molecular Formulas * John S. Hutchinson This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 3.0 1 Introduction
More informationChapter 11. Preview. Lesson Starter Objectives Pressure and Force Dalton s Law of Partial Pressures
Preview Lesson Starter Objectives Pressure and Force Dalton s Law of Partial Pressures Section 1 Gases and Pressure Lesson Starter Make a list of gases you already know about. Separate your list into elements,
More informationVocabulary atom atomos Dalton's atomic theory law of constant composition law of definite proportions law of multiple proportions matter.
1.3 Early Atomic Theory Lesson Objectives The student will: define matter and explain how it is composed of building blocks known as atoms. give a short history of how the concept of the atom developed.
More informationA brief history of Chemistry. Science 9- Mr. Klasz
A brief history of Chemistry Science 9- Mr. Klasz What is a pure substance? An element is a pure substance. A compound is made up of two or more elements which have been chemically compounded together.
More informationThe History of Atomic Theory Chapter 3--Chemistry
The History of Atomic Theory Chapter 3--Chemistry In this lesson, we ll learn about the men whose quests for knowledge about the fundamental nature of the universe helped define our views. The atomic model
More informationProperties of Gases. Molecular interactions van der Waals equation Principle of corresponding states
Properties of Gases Chapter 1 of Atkins and de Paula The Perfect Gas States of gases Gas laws Real Gases Molecular interactions van der Waals equation Principle of corresponding states Kinetic Model of
More information3.01 Understanding Atoms
3.01 Understanding Atoms The Events Leading to the Discovery of the Building Block of Matter Dr. Fred Omega Garces Chemistry 111 Miramar College 1 3.02 Atomic Evolution Environmental Problems in our Lifetime
More information-Dense and soft, which we are using to drink water, or in general all other liquids. They have
National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) Associate Professor Andrey OLCHAK, DSc EdEx Course How Our World Is Designed? Supporting material Primary Elements of Matter
More informationMatter What is Chemistry? Chemistry is the study of matter and the changes it undergoes.
Matter What is Chemistry? Chemistry is the study of matter and the changes it undergoes. What is matter? Matter is anything that has mass and occupies space. Chemists use a scientific method to study matter.
More informationChemistry Chapter 3. Atoms: The Building Blocks of Matter
Chemistry Chapter 3 Atoms: The Building Blocks of Matter I. From Philosophical Idea to Scientific Theory History of the Atom The Ancient Greeks were the first to come up with the idea of the atom. Democritus
More informationHie-Joon Kim. Professor Emeritus Seoul National University. Experience. Representative Publications
Hie-Joon Kim Professor Emeritus Seoul National University B.S. Chemistry, Seoul National University, Korea, 1970 Ph.D. Chemistry, University of Chicago, USA, 1977 Experience Professor, Department of Chemistry
More informationMatter and Energy Einstein (1905) E = mc2
Resumé What is Science? Domain: Science and the physical world Assumptions: A rational, causal, and understandable universe Methodology: The Scientific Method Observation, Hypothesis, Prediction, Testing
More informationCHAPTER 2 Building Blocks of Materials
CHAPTER 2 Building Blocks of Materials Matter is everything that is around us that we interact with anything that occupies space and has mass. A classification scheme that you have likely seen. Chapter
More informationPowerPoint lecture notes for Thornton/Rex s Modern Physics, 4e
PowerPoint lecture notes for Thornton/Rex s Modern Physics, 4e Prepared by: Anthony Pitucco, Ph.D. Pima Community College Dept of Physics, Chair Tucson, Arizona CHAPTER 1 The Birth of Modern Physics 1.1
More informationAtomic Structure. A model uses familiar ideas to explain unfamiliar facts observed in nature.
Atomic Structure 1 2 This model of the atom may look familiar to you. This is the Bohr model. In this model, the nucleus is orbited by electrons, which are in different energy levels. A model uses familiar
More informationChemistry 11. Unit 5 The Mole Concept
1 Chemistry 11 Unit 5 The Mole Concept 2 1. Atomic mass and Avodagro s hypothesis It has been studied that during a chemical reaction, atoms that make up the starting material rearrange to form new and
More informationHOMEWORK 11-1 (pp )
CHAPTER 11 HOMEWORK 11-1 (pp. 333 335) VOCABULARY Define. 1. Gay-Lussac s law of combining volumes of gases 2. Avogadro s law Answer each question. 3. Write and explain the equation that expresses the
More informationNuclear Chemistry. Atomic Structure Notes Start on Slide 20 from the second class lecture
Nuclear Chemistry Atomic Structure Notes Start on Slide 20 from the second class lecture The Birth of an Idea Democritus, 400 B.C. coined the term atom If you divide matter into smaller and smaller pieces,
More informationChapter 1: Matter, Energy, and the Origins of the Universe
Chapter 1: Matter, Energy, and the Origins of the Universe Problems: 1.1-1.40, 1.43-1.98 science: study of nature that results in a logical explanation of the observations chemistry: study of matter, its
More informationConceptual Physics Matter Atoms
Conceptual Physics Matter Atoms Lana Sheridan De Anza College July 20, 2017 Last time projectile motion orbits escape speed heliocentric model Kepler s laws review Overview matter atoms elements atomic
More informationCHEMISTRY. Matter and Change. Table Of Contents. Section 4.1 Early Ideas About Matter. Unstable Nuclei and Radioactive Decay
CHEMISTRY 4 Table Of Contents Matter and Change Section 4.1 Early Ideas About Matter Chapter 4: The Structure of the Atom Section 4.2 Section 4.3 Section 4.4 Defining the Atom How Atoms Differ Unstable
More information2 History of the Atomic
www.ck12.org CHAPTER 2 History of the Atomic Theory Chapter Outline 2.1 DEMOCRITUS IDEA OF THE ATOM 2.2 DALTON S ATOMIC THEORY 2.3 THOMSON S ATOMIC MODEL 2.4 RUTHERFORD S ATOMIC MODEL 2.5 BOHR S ATOMIC
More informationChapter Two: Early History of Chemistry. Three Important Laws. Dalton s Atomic Theory (1808) Three Important Laws (continued) Greek Explanation
Greek Explanation Chapter Two: ATOMS, MOLECULES, AND IONS Notes 2.1 In the Greek model they theorized there were four elements earth, water, air, and fire. These elements were characterized by the following
More informationOrigins of the Atom. Atoms: The Building Blocks of Matter. Let s Get Ready to Rumble. Aristotle s Theory of the Atom CHAPTER 3
Origins of the Atom CHAPTER 3 Atoms: The Building Blocks of Matter Let s Get Ready to Rumble The idea of the atom was met with great skepticism, especially among great thinkers. The most vocal critic of
More informationChem 161. Dr. Jasmine Bryant
Chem 161 Dr. Jasmine Bryant Chapter 1: Matter, Energy, and the Origins of the Universe Problems: 1.1-1.10, 1.14-1.22, 1.24-1.93, 1.96 Science: study of nature that results in a logical explanation of the
More informationCh 6 Gases 6 GASES. Property of gases. pressure = force/area
6 GASES Gases are one of the three states of matter, and while this state is indispensable for chemistry's study of matter, this chapter mainly considers the relationships between volume, temperature and
More informationIf You Cut a Piece of Graphite
Lecture Presentation Chapter 2 Atoms and Elements If You Cut a Piece of Graphite If you cut a piece of graphite from the tip of a pencil into smaller and smaller pieces, how far could you go? Could you
More informationName: Block Unit 3- The Atom
Name: Block Unit 3- The Atom DEMOCRITUS 1. Was Democritus a scientist? Notes 2. In what time of history did he live? 3. Describe Democritus thoughts about gold. 4. What was Democritus word for something
More informationAlthough different gasses may differ widely in their chemical properties, they share many physical properties
IV. Gases (text Chapter 9) A. Overview of Chapter 9 B. Properties of gases 1. Ideal gas law 2. Dalton s law of partial pressures, etc. C. Kinetic Theory 1. Particulate model of gases. 2. Temperature and
More informationUnit 2 continued-chemical Foundations Atoms, Ions, &Elements
Unit 2 continuedchemical Foundations Atoms, Ions, &Elements The Elements Most abundant elements in/on Earth: Oxygen 49.2% Silicon25.7% Most abundant in the human body: Oxygen65.0% Carbon18.0 % Hydrogen10.0%
More informationAmount of Substance and Its Unit Mole- Connecting the Invisible Micro World to the Observable Macro World Part 2 (English, mp4)
Amount of Substance and Its Unit Mole- Connecting the Invisible Micro World to the Observable Macro World Part 2 (English, mp4) [MUSIC PLAYING] Instructor: Hi, everyone. Welcome back. I hope you had some
More informationHow we found about ATOMS
How we found about ATOMS Isaac Asimov (Isaac Asimov is a master storyteller, one of the world s greatest writers of science fiction. He is also a noted expert on the history of scientific development,
More informationLesson 1.2 Classifying Matter
Lesson 1.2 Classifying Matter Vocabulary element atom chemical bond mixture molecule compound chemical formula What is Matter Made Of? What is matter? Why is one kind of matter different from another kind
More informationUnit 4 Class Notes Page
Name: Veritas: Unit 4 Class Notes Page 107 Unit 4 Class Notes Page 108 Name: Veritas: Unit 4, Worksheet 1 Types of Matter Read the following information on elements, compounds and mixtures. Fill in the
More informationCHAPTER -4 STRUCTURE OF ATOM CONCEPT DETAILS
CHAPTER -4 STRUCTURE OF ATOM CONCEPT DETAILS KEY CONCEPTS : [ *rating as per the significance of concept] 1. Dalton s Atomic theory ** 2. J J Thomson Experiments *** 3. Rutherford s Scattering Experiments
More informationParticle Theory of Matter. By the late 1700s, scientists had adopted the Particle Theory of Matter. This theory states that:
Particle Theory of Matter By the late 1700s, scientists had adopted the Particle Theory of Matter. This theory states that: all matter is made up of very tiny particles each pure substance has its own
More informationTHE ATOM atoms. electrons nucleus, protons neutrons atomic number atomic weight isotopes
1 THE ATOM All matter is made up of atoms. An atom is made up of two major parts: First, there is a cloud of electrons (very light, negatively charged particles filling most of the volume), and second,
More informationLecture Presentation. Chapter 2. Atoms and Elements. Christian Madu, Ph.D. Collin College Pearson Education, Inc.
Lecture Presentation Chapter 2 Atoms and Elements Christian Madu, Ph.D. Collin College If You Cut a Piece of Graphite If you cut a piece of graphite from the tip of a pencil into smaller and smaller pieces,
More informationUNIT 2 Atomic Structure
UNIT 2 Atomic Structure Section 1: History & Development of Atomic Theory (Chapter 3) History of the Atom Video The Greeks Democritus World made of empty space and tiny particles ( atoms ) Thought there
More informationAtoms, Molecules, Formula, and Subatomic Particles
Atoms Atoms, Molecules, Formula, and Subatomic Particles Atoms are the immensely small particles of which all matter is composed. How small are atoms? They are so small that they have only been able to
More informationCHEMISTRY Matter and Change. Chapter 4: The Structure of the Atom
CHEMISTRY Matter and Change Chapter 4: The Structure of the Atom CHAPTER 4 Table Of Contents Section 4.1 Section 4.2 Section 4.3 Section 4.4 Early Ideas About Matter Defining the Atom How Atoms Differ
More informationThe Phlogiston Theory
The Phlogiston Theory metal + heat = calx of metal + Ø e.g., zinc = zinc oxide + Ø phlogiston (Ø) is lost calx + charcoal(ø) + heat = metal + (fixed air) phlogiston (Ø) is gained Problem: Georg Ernest
More informationUNIT 5 : STATES OF MATTER Concept 1. INTERMOLECULAR FORCES
www.tiwariacademy.in UNIT 5 : STATES OF MATTER CONCEPT WISE HANDOUTS KEY CONCEPTS : 1. Intermolecular Forces 2. Gas Laws 3. Behaviour of gases Concept 1. INTERMOLECULAR FORCES Intermolecular forces- forces
More informationScience In Action 9 - Unit 1 Matter and Chemical Change Summary of Key Concepts and Review Questions Booklet
10. Matter can be described and organized by its physical and chemical properties Key Concepts Workplace Hazardous Materials Information System (WHMIS) and safety substances and their properties. Recognition
More informationChemistry and Atoms! 8 th grade history information to help you understand the background of how our knowledge grew through the years.
Chemistry and Atoms! 8 th grade history information to help you understand the background of how our knowledge grew through the years. Chemistry lies at the roots of civilization! Chemical reactions are
More informationElements. Chem101 - Lecture 2. Elements. Elements. Elements. Elements. Atoms and Molecules
Chem101 - Lecture 2 Atoms and Molecules Elements Elements are pure substances containing only one kind of atom (homoatomic). There are at last count 114 elements. (Your book indicates 112.). - 88 of these
More informationCHEMISTRY - ZUMDAHL 2E CH.1 - CHEMICAL FOUNDATIONS.
!! www.clutchprep.com CONCEPT: MATTER Chemistry is the study of matter and the changes it undergoes, with the being its basic functional unit. When two or more of these elements chemically bond together
More informationScience Class 9 th ATOMS AND MOLECULES. Symbols of Atoms of Different Elements. Atomic Mass. Molecules. Ions. Mole Concept. Finish Line & Beyond
Science Class 9 th ATOMS AND MOLECULES Symbols of Atoms of Different Elements Atomic Mass Molecules Ions Mole Concept Atom An atom is a particle of matter that uniquely defines a chemical element. An atom
More informationChapter 2: Atoms and Elements
C h e m i s t r y 1 A : C h a p t e r 2 P a g e 1 Chapter 2: Atoms and Elements Homework: Read Chapter 2: Work out sample and practice problems in textbook. Check for the MasteringChemistry.com assignment
More informationChemistry Physical and Chemical Changes in Matter
Physical and Chemical Changes in Matter Expanding Science Skills Series By Dr. Barbara R. Sandall Consultants: Schyrlet Cameron and Carolyn Craig COPYRIGHT 2010 Mark Twain Media, Inc. ISBN 978-1-58037-955-7
More information4.1 Defining the Atom > Chapter 4 Atomic Structure. 4.1 Defining the Atom. 4.2 Structure of the Nuclear Atom. 4.3 Distinguishing Among Atoms
Chapter 4 Atomic Structure 4.1 Defining the Atom 4.2 Structure of the Nuclear Atom 4.3 Distinguishing Among Atoms 1 Copyright Pearson Education, Inc., or its affiliates. All Rights Reserved. CHEMISTRY
More informationChapter 2: ATOMS. Outline of today s class:
Chapter 2: ATOMS Outline of today s class: The atomic idea (example for the significance of modern physics) Chemical elements, molecules, periodic table Temperature/warmth Units & powers of ten Examples
More informationInvestigating Atoms and Atomic Theory
Investigating Atoms and Atomic Theory Students should be able to: Describe the particle theory of matter. PS.2a Use the Bohr model to differentiate among the three basic particles in the atom (proton,
More informationTHE CORPUSCULAR NATURE OF MATTER AND ITS PHYSICAL STATES
THE CORPUSCULAR NATURE OF MATTER AND ITS PHYSICAL STATES In this unit we are going to study the matter from a microscopic point of view using the kinetic theory. We will understand the properties of the
More informationScientist wanted to understand how the atom looked. It was known that matter was neutral. It was known that matter had mass
Atom Models Scientist wanted to understand how the atom looked It was known that matter was neutral It was known that matter had mass They used these ideas to come up with their models, however science
More informationRemember that the size of an atom is on the order of m
Atomic hysics Remember that the size of an atom is on the order of 0-0 m rior to about 900, physics was generally concerned with describing macroscopic phenomena. macroscopic large scale, generally observable
More informationVijaykumar N. Nazare
Std-XI science Unit 1: Some Basic Concepts of Chemistry Vijaykumar N. Nazare Grade I Teacher in Chemistry (Senior Scale) vnn001@ chowgules.ac.in 1.1 IMPORTANCE OF CHEMISTRY Chemistry is the branch of science
More informationThe fundamental difference between. particles.
Gases, Liquids and Solids David A. Katz Department of Chemistry Pima Community College States of Matter The fundamental difference between states t of matter is the distance between particles. States of
More informationPhysics 205 Modern Physics for Engineers
Physics 205 Modern Physics for Engineers Instructor Professor Duncan Carlsmith Department of Physics duncan@hep.wisc.edu 262-2485 4285 Chamberlin Physics 205 Course Information http:// www.physics.wisc.e
More informationThe history of the concept of element, with particular reference to Humphry Davy
The history of the concept of element, with particular reference to Humphry Davy One of the problems highlighted when the recently implemented chemistry syllabus was being developed was the difficulty
More informationCHAPTER 3: MATTER. Active Learning Questions: 1-6, 9, 13-14; End-of-Chapter Questions: 1-18, 20, 24-32, 38-42, 44, 49-52, 55-56, 61-64
CHAPTER 3: MATTER Active Learning Questions: 1-6, 9, 13-14; End-of-Chapter Questions: 1-18, 20, 24-32, 38-42, 44, 49-52, 55-56, 61-64 3.1 MATTER Matter: Anything that has mass and occupies volume We study
More informationChapter 2: An Evolving Model
Physical Science 4010 Nuclear Technology Chapter 2: An Evolving Model Introduction The universe is made up of two things: Matter (physical, tangible stuff) Energy (more than just the ability to do work)
More informationParticle Charge Mass Location Proton + 1 In nucleus Neutron O 1 In nucleus Electron -- Small fraction of proton 1/1837
ATOM UNIT NOTES: Building Blocks of Matter: The atom is the smallest piece that keeps the properties/characteristics of that type of particle. They are the building blocks of matter. Atoms are made of
More informationChapter 2: ATOMS. Outline of today s class:
Chapter 2: ATOMS Outline of today s class: The atomic idea (example for the significance of modern physics) Chemical elements, molecules, periodic table Temperature/warmth Units & powers of ten Examples
More informationAtomic Theory. Introducing the Atomic Theory:
Atomic Theory Chemistry is the science of matter. Matter is made up of things called atoms, elements, and molecules. But have you ever wondered if atoms and molecules are real? Would you be surprised to
More informationChapter 4: Atomic Structure Section 4.1 Defining the Atom
Chapter 4: Atomic Structure Section 4.1 Defining the Atom Early Models of the Atom atom the smallest particle of an element that retains its identity in a chemical reaction Democritus s Atomic Philosophy
More informationTHE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL CERTIFICATE OF SECONDARY EDUCATION EXAMINATION
THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL CERTIFICATE OF SECONDARY EDUCATION EXAMINATION 032/1 CHEMISTRY 1 (For Both School and Private Candidates) Time: 3 Hours Thursday, 06 th November
More informationChapter 02 Test Bank: Atoms, Ions, and the Periodic Table
Introduction to Chemistry 4th Edition Bauer Test Bank Full Download: http://testbanklive.com/download/introduction-to-chemistry-4th-edition-bauer-test-bank/ Chapter 02 Test Bank: Atoms, Ions, and the Periodic
More informationChapter 1. Chemical Foundations
Chapter 1 Chemical Foundations Chapter 1 Table of Contents (1.1) (1.2) (1.3) (1.4) (1.5) (1.6) (1.7) Chemistry: An atoms-first approach The scientific method The early history of chemistry Fundamental
More informationCLIL Content Language Integrated Learning
Atomos CLIL Content Language Integrated Learning PET - Preliminary English Test Teacher: Mr Pierluigi Stroppa Tutor: Mrs Angela Valentini 1 Investigating atoms You should be able to: Describe the particle
More informationThe Fundamental Laws of Chemistry
The Fundamental Laws of Chemistry As we have discussed, matter can be classified into different categories based on directly observable properties, be they physical or chemical. Heterogeneous systems contain
More informationStructure of matter I
Structure of matter I "Could anything at first sight seem more impractical than a body which is so small that its mass is an insignificant fraction of the mass of an atom of hydrogen?" J.J. Thomson, about
More informationRepresenting Chemical Change
Representing Chemical Change As we have already mentioned, a number of changes can occur when elements react with one another. These changes may either be physical or chemical. One way of representing
More informationActivity 2 Elements and Their Properties
Activity 2 Elements and Their Properties Activity 2 Elements and Their Properties GOALS In this activity you will: Apply ancient definitions of elements to materials you believe are elements. Test some
More informationC1403 Lecture 3, Wednesday, September 14, Water
C1403 Lecture 3, Wednesday, September 14, 2005 o Water 1 Water, water, everywhere, Nor any drop to drink. Samuel Taylor Coleridge, The Rime of the Ancient Mariner, 1798. If there is magic on this planet,
More informationHIGH SCHOOL SCIENCE. Physical Science 9: Atomic Structure
HIGH SCHOOL SCIENCE Physical Science 9: Atomic Structure WILLMAR PUBLIC SCHOOL 2013-2014 EDITION CHAPTER 9 Atomic Structure In this chapter you will: 1. Compare and contrast quarks, leptons, and bosons.
More informationNatural Sciences 1: Laws and Models in Chemistry
Natural Sciences 1: Laws and Models in Chemistry Natural Sciences 1: Laws and Models in Chemistry, traces the efforts in Western thought to understand what makes up the physical world what remains the
More informationChapter 4. History of the atom. History of Atom Smallest possible piece? Atomos - not to be cut. Atoms and their structure
Chapter 4 Atoms and their structure History of the atom Not the history of atom, but the idea of the atom. Original idea Ancient Greece (400 B.C.) Democritus and Leucippus Greek philosophers. Looked at
More informationAP Atomic Structure Models
AP Atomic Structure Models What is a Model? On a scrap piece of paper, write down your definition of a model with at least two examples. A model is a representation of an object, idea, action, or concept.
More informationChapter 5. Stoichiometry
Chapter 5 Stoichiometry Chapter 5 Table of Contents (5-1) Counting by weighing (5-2) Atomic masses (5-3) Learning to solve problems (5-4) The mole (5-5) Molar mass (5-6) Percent composition of compounds
More informationAP CHEMISTRY READING GUIDE
Name: Due Date: AP CHEMISTRY READING GUIDE Chapters 1-3, Chemical Foundations & Stoichiometry Chapter 1 Chemical Foundations Define the following terms in your own words: Scanning Tunneling Microscope
More informationChemistry and Atoms! 8 th grade history information to help you understand the background of how our knowledge grew through the years.
Chemistry and Atoms! 8 th grade history information to help you understand the background of how our knowledge grew through the years. Chemistry lies at the roots of civilization! Chemical reactions are
More informationEXPERIMENT 17. To Determine Avogadro s Number by Observations on Brownian Motion. Introduction
EXPERIMENT 17 To Determine Avogadro s Number by Observations on Brownian Motion Introduction In 1827 Robert Brown, using a microscope, observed that very small pollen grains suspended in water appeared
More informationCHEMISTRY. Chapter 6 Electronic Structure of Atoms
CHEMISTRY The Central Science 8 th Edition Chapter 6 Electronic Structure of Atoms Kozet YAPSAKLI Who are these men? Ancient Philosophy Who: Aristotle, Democritus When: More than 2000 years ago Where:
More informationTHE ATOM Pearson Education, Inc.
THE ATOM Title and Highlight Right Side NOTES ONLY TN Ch 4.1-4.2 Topic: EQ: Date Reflect Question: Reflect on the material by asking a question (its not suppose to be answered from notes) NOTES: Write
More information4-1 Notes. Defining the Atom
4-1 Notes Defining the Atom Early Models of the Atom All matter is composed of atoms Atoms are the smallest particles of an element that retains their identity in a chemical reaction Greek philosopher
More informationCHEMISTRY - TRO 4E CH.2 - ATOMS & ELEMENTS.
!! www.clutchprep.com CONCEPT: GROUP NAMES AND CLASSIFICATIONS Ever wonder where did this periodic table ever come from? At the end of the 18 th century, Lavoisier compiled a list of the 23 elements known
More informationCHEMISTRY - MCMURRY 7E CH.2 - ATOMS, MOLECULES AND IONS.
!! www.clutchprep.com CONCEPT: GROUP NAMES AND CLASSIFICATIONS Ever wonder where did this periodic table ever come from? At the end of the 18 th century, Lavoisier compiled a list of the 23 elements known
More information