...Atoms, Molecules, and Elements Atoms, Molecules, and Elements Take a look out the window. Consider that everything that you can and cannot see is composed of atoms. Some of these may be bonded with other atoms to form molecules. All matter is composed of atoms that are too small to see. Weather the matter is liquid, gas or solid, pure or a mixture. It is the basis for elements that make up what we know today as our periodic table. Demetri Mendeleev was trying to organize the elements into a table by weight when he noticed that as the weights increase occasionally the properties of one element would resemble those of an element he already listed so he placed these elements in a column under the ones they resembled chemically ( Capri, PhD, 2003). Each chemical in the vertical rows on the periodic table are considered families or groups because they have properties that are similar to each other. All the chemicals in group 1A of the periodic table are considered alkali metals. Alkali metals are similar in that each of them has only one atom in the outermost shell and they are very reactive when combined with other elements. All elements in column 7A are halogens. Halogens are also highly reactive oxidizing agents that are called “salts”. All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1 ( Bodner Research Web, n.d.). Noble gases can be found in Column 8A. These elements are all considered to belong in this column because they are all...
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...What is a molecule? Well, simply put it's just a group of atoms bonded together. However, there are special molecules; these are polar and nonpolar molecules. Molecules make us up, they are made up of atoms. Which have electrons, electrons are little balls with a negative charge, and like magnets opposite attract. This brings us to electronegativity. Electronegativity is a measure of the tendency towards an atom to attract a bonding pair of electrons. What is a polar molecule? Simply put, it's a particle that has two or more covalently bonded atoms. (A covalent bond is a bond where two atoms share their electrons to become stable ) With an asymmetric distribution of changes, this occurs to molecules that are asymmetric along at least one axis....
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...STRUCTURAL ORGANIC CHEMISTRY. THE SHAPES OF MOLECULES. FUNCTIONAL GROUPS I n this chapter we first briefly review the most important types of covalent bonds encountered in organic substances and the ways in which these bonds are represented in structural formulas. Next we consider the sizes and shapes of organic molecules and how structural formulas written in two dimensions can be translated into three-dimensional models that show the relative positions of the atoms in space. We also discuss models that reflect the relative sizes of the atoms and the way in which the atoms may interfere with each other when in close quarters (steric hindrance). Then we go on to further important aspects of structure-the functional group concept and position isomerism. Our aim is to have you become more familiar with the various kinds of organic compounds and begin to see how the practicing organic chemist visualizes molecules and correlates the diverse kinds of structures that he has to deal with in his work. 2-1 STRUCTURAL FORMULAS The building block of structural organic chemistry is the tetravalent carbon atom. With few exceptions, carbon compounds can be formulated with four 2-1 Structural Fbrmulas 31 covalent bonds to each carbon, regardless of whether the combination is with carbon or some other element. The two-electron bond, which is illustrated by the carbon-hydrogen bonds in methane or ethane and the carbon-carbon bond in ethane, is called a single...
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...201210135 Group Members: Chanelle Leach CH 112L-03 Kevion Young General Chemistry II Lab Zakita Jones February 25, 2014 –March 25, 2014 Labs # 3 and 4 Title: Chemical Bonding Lewis Structures and Shapes of Molecules and Ions References/Tools: 1. Chapter 9: Models of Chemical Bonding 2. Chapter 10: The Shapes of Molecules 3. The Modern Periodic Table 4. Electron Configuration (SPDF notation, Orbital diagram), Lewis Symbols, Lewis Structures, Molecular Formulas, and Molecular Diagrams 5. Ion and Molecules, Tetrahedral Geometry (109 degrees) , Planar Geometry (120 degrees), and Linear geometry (180 degrees) 6. Page 279 7. VESPR Theory (Chapter 10) (Valence Electrons Pair Repulsion Theory) Objective: To learn and study about chemical bonding, chemical formulas, Lewis structures, bond angles, geometry and shapes of molecules and molecular ions. Definitions/Concepts/Theories/Formulas Chapter 9 1. Ionic Bonding- the complete transfer of valence electrons between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the non-metal accepts those electrons to become a negatively charged anion. 2. Covalent Bonding- a chemical...
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...Chapter 10 Outline The Shapes of Molecules Introduction Whether we consider the details of simple reactions, the properties of synthetic material, or the intricate life-sustaining processes of living cells, molecular shape is a crucial factor. 10.1 Depicting Molecules and Ions with Lewis Structures Lewis structures, also called electron-dot structures or electron-dot diagrams, are diagrams that show the bonding between atoms of a molecule, and the lone pairs of electrons that may exist in the molecule. A Lewis structure can be drawn for any covalently-bonded molecule, as well as coordination compounds. Using the Octet Rule to Write Lewis Structures The octet rule tells us that all atoms want eight valence electrons (except for hydrogen, which wants only two), so they can be like the nearest noble gas. Use the octet rule to figure out how many electrons each atom in the molecule should have, and add them up. The only weird element is boron - it wants six electrons. Lewis Structures for Molecules with Single Bonds The atoms share a pair of electrons, and that pair is referred to as a bonding pair. The pairs of electrons which do not participate in the bond have traditionally been called "lone pairs". A single bond can be represented by the two dots of the bonding pair, or by a single line which represents that pair. The single line representation for a bond is commonly used in drawing Lewis structures for molecules. · Hydrogen atoms form one bond. · Carbon...
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...Chapter 2: Chemistry and molecules of life -Homeostasis- The maintenance of an internal environment -Energy- The ability to do work -Metabolism- Chemical reactions in a cell that allows it to use energy -Element- A chemically pure substance that cannot not be broken down -Matter- anything that takes of space -Atom- smallest unit of an element -Proton- positively charged particle inside nucleus -Electron- negatively charged particle around nucleus -Neutron- uncharged particle inside nucleus -Nucleus- core of an atom -Covalent Bond- strong bond from the sharing of electrons between two atoms -Molecule- atoms together by covalent bond -Organic Molecule- carbon based molecule with at least one C-H bond -Inorganic Molecule- lacks carbon and C-H bond -Carbohydrate- organic molecule made up of sugars -Protein- organic molecule made up of amino acid -Lipids- organic molecule that repels water -Nucleic Acids- organic molecule made of nucleotides DNA/RNA -Macromolecules- organic molecules made up of living organisms (carbohydrates,protiens,nucleic acids) -Monomer- one chemical subunit -Polymer- molecule made up of individual subunits -Monosaccharide- monomer of a carbohydrate -Amino Acid- monomer of a protein -Nucleotide- monomer of a nucleic acid -Cell- basic structure of living organisms -Phospholipid- lipid that forms a cell membrane -Phospholipid Bilayer- double layer lipid that characterizes biological...
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...Pure chemical substances are classified as ionic, metallic, covalent molecular and covalent network. In this essay I will describe the nature of each bonding present in these different types of substances and use this to explain the physical properties they exhibit and their structures. Ionic compounds are compounds that are composed of positive and negative ions. An ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. Usually, the positively charged portion consists of metal (cations) and the negatively charged portion is an (anion) or polyatomic ion. Ions in ionic compounds are held together by the electrostatic forces between oppositely charged bodies. The positive and negative ions in these compounds are thought to be arranged in an orderly three-dimensional lattice. For example, the structure of sodium chloride is shown. In the lattice, each positive sodium ion is surrounded by six negative chloride ions and each negative chloride ion is surrounded by six positive sodium ions. The position of the ions is fixed and apart from vibration about these fixed positions no other movement of the ions occurs in the solid compound. Each ion in an ionic solid is held in the crystal lattice by strong electrostatic attractions to the oppositely charged ions around it. These electrostatic forces between the positive and negative ions are called ionic bonds. Because ionic compounds have high melting points, in other words considerable...
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...Biology 10 Study Guide #1 1. List some of the characteristics that distinguish living from non-living things. 2. Outline the basic steps of inquiry included in the scientific method. 3. What is the difference between a hypothesis, a theory and an opinion? 4. What is homeostasis? 5. Be able to summarize the basic idea represented by each of the 10 majors themes that form the cornerstones for understanding Biology. Be able to provide an example for each of these. The Chemistry of Life: 1. If you were probing for life on a distant planet, what could you look for to determine whether it was even possible for life to exist, or to have existed, there. Why is each of things you’ve identified important to life. 2. Review the definition of an atom. What is meant by the idea that it is “the smallest unit of a pure substance that retains properties of that substance”? 3. Understand the nature and arrangement of the subatomic structure of atoms. Where are the subatomic particles found? 4. Why are we concerned about whether atoms are reactive or not? 5. What determines whether a particular element (type of atom) is reactive? 6. Understand the difference between inert elements and those that are reactive and capable of forming chemical bonds. What is the significance of the valance shell of electrons? 7. Why do atoms seek to form bonds with other atoms? How does this correlate with their stability? 8. Understand the nature of...
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...Name Lab Section Date The Mole Concept and Atomic Weights Text Reference: Tro, Chemistry: Structure and Properties Section 2.8 - Atoms and the Mole: How Many Particles? Section 1.9 – Atomic Mass: The Average of an Element’s Atoms The purpose of this activity is to better understand the concepts of relative atomic mass, counting by weighing and the mole. Per cent composition and average atomic mass are included. Part I. Relative Atomic Masses and the Mole – Early Method When John Dalton proposed his atomic theory, he stated that the atoms of each element had a characteristic mass. He carried out experiments to determine the relative atomic mass of each element. To do this, he had to establish a standard because a single atom was too small to weigh. The standard he chose was that the mass of hydrogen would be set equal to 1.000. In a simple experiment, Dalton would measure the grams of an element such as sulfur that reacted with 1.00 gram of hydrogen. For sulfur, the reacting mass was found to be 32.0 grams, and so 32.0 was the relative mass of sulfur with respect to the standard hydrogen. (Note: The current standard for atomic mass is the most abundant isotope of carbon, C-12, with an assigned mass of exactly 12.000 amu.) The following activity will demonstrate how the relative mass method works. 1. Weigh five of the red color balls to three decimal places. Be sure to tare out the mass of the plastic cup. Record the mass in the table below. 2. Weigh five...
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... A theoretical approach to describe the mechanisms of the isomerization and reduction of a double bond, involved in the lanosterol conversion to cholesterol was undertaken. Also, the 14α-demethylation and 4α-demethylation in this biosynthesis were studied, and some similarities were found between the two; however they are different and their mechanisms have not been explained yet. Ab initio calculations were performed in order to prove these mechanisms. Two different characteristics involved in this biosynthesis were explained, namely (i) the stability of each molecule during this reaction using total energy, hardness and dipole moment, and (ii) the explanation of proposed mechanisms [Steroid Biochemistry and Pharmacology, 1970, p. 57] of the two different reactions, using frontier orbitals and atomic charges. For this sequence of reactions, the hardness and dipole moment indicate the hydro-solubility of the molecules, which means that carrying properties change through cell membrane. It is possible to explain the reaction mechanisms using frontier molecular orbitals theory and the atomic charge. The localization of highest occupied molecular orbital, lowest unoccupied molecular orbital and the flow of atomic charge are in agreement with reported mechanisms [Steroids 8 (1966) 353; Medicinal Natural Products, 1997, p. 218; Biochemistry of Steroid Hormones, 1975. 1. Introduction Cholesterol is the main sterol in animal tissues and is an important constituent of...
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...around the glass closer to the side of the heavier substance (HCl, M = 36.4611 g/mole; dAve = 10.8 cm). The agar-water gel set up was composed of a petri dish of agar-water gel containing three wells. Drops of potassium permanganate (KMnO4), potassium dichromate (K2Cr2O7) and methylene blue were simultaneously introduced to each well. Methylene blue, having the largest molecular weight, displayed the smallest diameter (18 mm) and diffused at the slowest rate (0.3668 mm/min.). Thus, the higher the molecular weight, the slower the rate of diffusion. INTRODUCTION A substance in the gaseous or liquid state consists of molecules or atoms that are independent, rapid, and random in motion. These molecules frequently collide with each other and with the sides of the container. In a period of time, this movement results in a uniform distribution of the molecules throughout the system. This process is called diffusion (Everett and Everett, n.d.). Diffusion occurs naturally, with the net movement of particles flowing from an area of high concentration to an area of low concentration. Net diffusion can be restated as the movement of particles along the concentration gradient. 3 According to Meyertholen (n.d.), there are several factors which may affect the rate of diffusion of a substance. These factors include the size of the particle or the molecular weight of the substance, temperature or availability of energy...
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... |Iron (11) | |Cr+3 |1s22s22p63s23p63d54s2 |Chromium (111) | |Sr+2 |1s22s22p63s23p63d104s24p64d105s2 |Scandium | |Ni+2 |1s22s22p63s23p64s23d8 |Nickel (11) | |Cu+2 |1s22s22p63s23p63d104s1 |Copper (11) | 2. What is a molecule? Give 3 examples for diatomic molecules and draw their Lewis dot structures. In your structures, show the lone pair of electrons (unshared) and shared pair of electrons. A molecule is a neutral group of atoms joined together by covalent bonds. 3) Cobalt, a...
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...[pic] Official TCC Course Syllabus |Discipline Prefix: CHM |Course Number: 111 |Course Title: College Chemistry I | | |Course Section: D04B | | |Credit Hours: 4 |Lecture Hours: 3 |Clinical Hours: |Lab Hours: 3 | |Contact Hours: 6 |Studio Hours: N/A |Semester: Fall | |Meeting Days/Time/Location: Fridays/1:30pm-4:20pm/Science Building | Instructor Information Name: Dr. Shahin Maaref Office Location: JD-30 Office Hours: TRF 9:00am-11:00am, TR 4:30pm-5:30pm & by appointment Contact Information: 822-7692 Blackboard site: http://learn.vccs.edu Instructor email address: smaaref@tcc.edu Course Information Course Description Explores the fundamental laws, theories, and mathematical concepts of chemistry. Designed primarily for science and engineering majors. Requires a strong background in mathematics. Part I of II. Prerequisites and/or Co-requisites Prequisites - None Corequisites – None It is recommended to have H.S. chemistry or CHM01 as prerequisites and MTH 03 or MTE 06 level or higher. ...
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...Chemistry 105 Spring, 2013 Unit 2 Summary 4/25 Outcomes: 1. To review air quality issues related to fossil fuel consumption and the limitations of this resource. 2. To define energy, work, heat, and temperature in scientific (thermodynamic) terms, and how the terms calorie, nutritional Calorie, joule, and kilojoule are related. 3. To describe the First Law of Thermodynamics as the conservation of energy, and the interplay of kinetic, potential, heat and work energy. To describe and apply the Second Law of Thermodynamics from several points of view: randomness, chaos, probability, distribution of matter and energy, energy efficiency. 4. To know that we measure energy only through change, such as with a calorimeter. 5. To use potential energy diagrams to represent changes that take place in reactions 6. To use the terms endothermic and exothermic to describe the entry or exit of heat from chemical systems (and that the opposite change must take place in the surroundings). 7. To know that energy changes in reactions come from changes in chemical bonds, and how they can be estimated from differences in bond energies of bonds broken vs. formed. 8. To express and interpret these changes in potential energy diagrams and apply these skills to the combustion of fuels. 9. To view and describe recent trends in energy source utilization. 10. To give specific details on the composition of coal and its impacts on environmental quality. Assignments: Read §4.1 – 4...
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...CHAPTER 3 MASS RELATIONSHIPS IN CHEMICAL REACTIONS This chapter reviews the mole concept, balancing chemical equations, and stoichiometry. The topics covered in this chapter are: • Atomic mass and average atomic mass • A vogadro’ s number, mole, and molar mass • Percent composition calculations • Empirical and molecular formula determinations • Chemical equations, amount of reactant and product calculations • Limiting reagents and reaction yield calculations Take Note: It is absolutely essential that you master the mole concept to do well on the quantitative aspects of AP Chemistry!! When solving quantitative problems on the Free Response section of the AP exam, supporting work must be shown to receive credit. Using dimensional analysis is a very powerful technique in solving problems. Be sure to report your answer to the correct number of significant figures (see Chapter 1 in this review book). Atomic mass and average atomic mass Atomic mass is the mass of an atom in atomic mass units (amu). One amu is defined as 1/12 of one C-12 atom. The C-12 isotope has a mass of exactly 12.000 amu. The C-12 isotope provides the relative scale for the masses of the other elements. Average atomic mass is the value reported on the periodic table, which takes into account the various isotopes of an element and their respective frequencies. To calculate the average atomic mass of an element, add up the different masses of the isotopes (using amu) multiplied by each isotope’s abundance...
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