Flammability Limits: Thermodynamics and Kinetics
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Types of Chemical Reactions and Solution Stoichiometry
Types of Chemical Reactions 4 and Solution Stoichiometry Contents 4.1 Water, the Common Solvent 4.2 The Nature of Aqueous Solutions: Strong and Weak Electrolytes • Strong Electrolytes • Weak Electrolytes • Nonelectrolytes 4.3 The Composition of Solutions • Dilution 4.4 Types of Chemical Reactions 4.5 Precipitation Reactions 4.6 Describing Reactions in Solution 4.7 Stoichiometry of Precipitation Reactions 4.8 Acid–Base Reactions • Acid–Base Titrations 4.9 Oxidation–Reduction Reactions • Oxidation States • The Characteristics of Oxidation–Reduction Reactions 4.10 Balancing Oxidation– Reduction Equations • The Half-Reaction Method for Balancing Oxidation–Reduction Reactions in Aqueous Solutions Yellow lead(II) iodide is produced when lead(II) nitrate is mixed with potassium iodide. 126 Much of the chemistry that affects each of us occurs among substances dissolved in water. For example, virtually all the chemistry that makes life possible occurs in an aqueous environment. Also, various medical tests involve aqueous reactions, depending heavily on analyses of blood and other body fluids. In addition to the common tests for sugar, cholesterol, and iron, analyses for specific chemical markers allow detection of many diseases before obvious symptoms occur. Aqueous chemistry is also important in our environment. In recent years, contami- nation of the groundwater by substances such as chloroform and nitrates has been widely publicized. Water is essential for life, and the maintenance of an ample supply of clean water is crucial to all civilization. To understand the chemistry that occurs in such diverse places as the human body, the atmosphere, the groundwater, the oceans, the local water treatment plant, your hair as you shampoo it, and so on, we must understand how substances dissolved in water react with each other. -
Chapter 17: Electrochemistry
4/12/2021 17.1 Electrochemistry Chapter 17: Deals with chemical reactions that produce electricity and the changes associated Electrochemistry with the passage of charge through matter. Reactions involve electron transfer – oxidation/reduction (redox) Example: A typical AA alkaline battery is rated at 1.5 V. This means the electrical potential difference between the +/– terminals is 1.5 V. It is the chemical reactions in the battery that give rise to this difference. 1 2 1 2 Redox Recap Assigning oxidation numbers Oxidation number rules: 1.) Ox. # = 0 for an atom in pure, elemental state 2+ 2.) Ox. # = <charge> for monatomic ion: Ox. # = 2 for Ca Oxidation number: +1 –1 3.) Sum of all Ox. #’s for atoms in polyatomic ion = charge on polyatomic ion Total contribution to charge: +2 –2 = 0 4.) Sum of all Ox. #’s = charge on species: H2O Ox.(H) = 1, Ox(O) = –2 Oxidation number: +1 +6 –2 Total contribution to charge: +2 +6 –8 = 0 3 4 3 4 1 4/12/2021 Redox terminology Redox terminology applied Oxidation – the loss of electrons OIL RIG – “oxidation is losing, Reduction – the gain of electrons reduction is gaining” 0 +2 –1 +2 –1 0 “Substance X undergoes oxidation.” – X lost electrons 0 +2 –2 +2 –2 0 “Substance Y was reduced.” – Y gained electrons Oxidizing agent – the species that undergoes reduction What was oxidized? Zn Oxidizing agent = CuCl2 Reducing agent – the species that undergoes oxidation What was reduced? Cu2+ Reducing agent = Zn “Substance Z is the oxidizing agent.” – Z gains electrons What is the spectator ion? Cl– (Think: Travel agent – allows someone else to travel) 5 6 5 6 17.1 Balancing redox reactions Example: Balancing redox reaction in acidic solution 1.) Assign oxidation states to all atoms. -
1 Refinery and Petrochemical Processes
3 1 Refinery and Petrochemical Processes 1.1 Introduction The combination of high demand for electric cars and higher automobile engine effi- ciency in the future will mean less conversion of petroleum into fuels. However, the demand for petrochemicals is forecast to rise due to the increase in world popula- tion. With this, it is expected that modern and more innovative technologies will be developed to serve the growth of the petrochemical market. In a refinery process, petroleum is converted into petroleum intermediate prod- ucts, including gases, light/heavy naphtha, kerosene, diesel, light gas oil, heavy gas oil, and residue. From these intermediate refinery product streams, several fuels such as fuel gas, liquefied petroleum gas, gasoline, jet fuel, kerosene, auto diesel, and other heavy products such as lubricants, bunker oil, asphalt, and coke are obtained. In addition, these petroleum intermediates can be further processed and separated into products for petrochemical applications. In this chapter, petroleum will be introduced first. Petrochemicals will be intro- duced in the second part of the chapter. Petrochemicals – the main subject of this book – will address three major areas, (i) the production of the seven cornerstone petrochemicals: methane and synthesis gas, ethylene, propylene, butene, benzene, toluene, and xylenes; (ii) the uses of the seven cornerstone petrochemicals, and (iii) the technology to separate petrochemicals into individual components. 1.2 Petroleum Petroleum is derived from the Latin words “petra” and “oleum,” which means “rock” and “oil,” respectively. Petroleum also is known as crude oil or fossil fuel. It is a thick, flammable, yellow-to-black mixture of gaseous, liquid, and solid hydrocarbons formed from the remains of plants and animals. -
Dehydrogenation by Heterogeneous Catalysts
Dehydrogenation by Heterogeneous Catalysts Daniel E. Resasco School of Chemical Engineering and Materials Science University of Oklahoma Encyclopedia of Catalysis January, 2000 1. INTRODUCTION Catalytic dehydrogenation of alkanes is an endothermic reaction, which occurs with an increase in the number of moles and can be represented by the expression Alkane ! Olefin + Hydrogen This reaction cannot be carried out thermally because it is highly unfavorable compared to the cracking of the hydrocarbon, since the C-C bond strength (about 246 kJ/mol) is much lower than that of the C-H bond (about 363 kJ/mol). However, in the presence of a suitable catalyst, dehydrogenation can be carried out with minimal C-C bond rupture. The strong C-H bond is a closed-shell σ orbital that can be activated by oxide or metal catalysts. Oxides can activate the C-H bond via hydrogen abstraction because they can form O-H bonds, which can have strengths comparable to that of the C- H bond. By contrast, metals cannot accomplish the hydrogen abstraction because the M- H bonds are much weaker than the C-H bond. However, the sum of the M-H and M-C bond strengths can exceed the C-H bond strength, making the process thermodynamically possible. In this case, the reaction is thought to proceed via a three centered transition state, which can be described as a metal atom inserting into the C-H bond. The C-H bond bridges across the metal atom until it breaks, followed by the formation of the corresponding M-H and M-C bonds.1 Therefore, dehydrogenation of alkanes can be carried out on oxides as well as on metal catalysts. -
Gas Stoichiometry 84 Mins
Chemistry 20 Unit 4 Lesson 3 - Gas Stoichiometry 84 mins Gas Stoichiometry - gas volume, pressure and temperature, molar If 275 g of propane burns in a gas barbecue, what volume, and the ideal gas law volume of oxygen measured at STP is required for the reaction? PV = nRT C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) 760.000 mmHg = 101.325 kPa = 1.00000 atm 275 g V = ?? R = 8.31451 LkPa/molK 44.11g/mol 32.00 g/mol STP = 0.00 °C, 101.325 kPa 1 mol nC3H8 = 275g × = 6.23 mol 44.11g/mol SATP = 25.00 °C, 100.00 kPa 5 mol of O2 nO2 = 6.23 mol × = 31.2 mol 1 mol of C3H8 nRT 31.2 mol ×8.31451×273.15K VO2 = = = 699 L P 101.325 kP a Gravimetric and Gas Stoichiometry Overview 1. Write a balanced chemical equation and list the A typical Alberta home heated with natural gas (assume measurements, unknown quantity symbol, and methane, CH4(g)) consumes 2.00 ML of natural gas conversion factors for the measured and required during the month of December. What volume of oxygen substances. at SATP is required to burn 2.00 ML of methane 2. Convert the measured quantity to a chemical measured at 0 °C and 120 kPa? amount using the appropriate conversion factor. 3. Calculate the chemical amount of the required CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) substance using the mole ratio from the balanced 2.00 ML V = ??? equation. = M = 4. Convert the calculated chemical amount to the 2.00 × 106L 32.00g/mol final quantity requested using the appropriate M = 16.05 conversion factor. -
Thermal Conductivity Correlations for Minor Constituent Fluids in Natural
Fluid Phase Equilibria 227 (2005) 47–55 Thermal conductivity correlations for minor constituent fluids in natural gas: n-octane, n-nonane and n-decaneଝ M.L. Huber∗, R.A. Perkins Physical and Chemical Properties Division, National Institute of Standards and Technology, Boulder, CO 80305, USA Received 21 July 2004; received in revised form 29 October 2004; accepted 29 October 2004 Abstract Natural gas, although predominantly comprised of methane, often contains small amounts of heavier hydrocarbons that contribute to its thermodynamic and transport properties. In this manuscript, we review the current literature and present new correlations for the thermal conductivity of the pure fluids n-octane, n-nonane, and n-decane that are valid over a wide range of fluid states, from the dilute-gas to the dense liquid, and include an enhancement in the critical region. The new correlations represent the thermal conductivity to within the uncertainty of the best experimental data and will be useful for researchers working on thermal conductivity models for natural gas and other hydrocarbon mixtures. © 2004 Elsevier B.V. All rights reserved. Keywords: Alkanes; Decane; Natural gas constituents; Nonane; Octane; Thermal conductivity 1. Introduction 2. Thermal conductivity correlation Natural gas is a mixture of many components. Wide- We represent the thermal conductivity λ of a pure fluid as ranging correlations for the thermal conductivity of the lower a sum of three contributions: alkanes, such as methane, ethane, propane, butane and isobu- λ ρ, T = λ T + λ ρ, T + λ ρ, T tane, have already been developed and are available in the lit- ( ) 0( ) r( ) c( ) (1) erature [1–6]. -
Measurements of Higher Alkanes Using NO Chemical Ionization in PTR-Tof-MS
Atmos. Chem. Phys., 20, 14123–14138, 2020 https://doi.org/10.5194/acp-20-14123-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Measurements of higher alkanes using NOC chemical ionization in PTR-ToF-MS: important contributions of higher alkanes to secondary organic aerosols in China Chaomin Wang1,2, Bin Yuan1,2, Caihong Wu1,2, Sihang Wang1,2, Jipeng Qi1,2, Baolin Wang3, Zelong Wang1,2, Weiwei Hu4, Wei Chen4, Chenshuo Ye5, Wenjie Wang5, Yele Sun6, Chen Wang3, Shan Huang1,2, Wei Song4, Xinming Wang4, Suxia Yang1,2, Shenyang Zhang1,2, Wanyun Xu7, Nan Ma1,2, Zhanyi Zhang1,2, Bin Jiang1,2, Hang Su8, Yafang Cheng8, Xuemei Wang1,2, and Min Shao1,2 1Institute for Environmental and Climate Research, Jinan University, 511443 Guangzhou, China 2Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, 511443 Guangzhou, China 3School of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), 250353 Jinan, China 4State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou, China 5State Joint Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, 100871 Beijing, China 6State Key Laboratory of Atmospheric Boundary Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese -
Stoichiometry: Predicting Amounts in Reactions
Name: Per: 4-4c: Stoichiometry: Predicting Amounts in Reactions Stoichiometry is the process of determining how much product is made or how much reactant is needed during a chemical reaction. As we know, in chemical reactions atoms are conserved. We show this in a balanced chemical equation. The balanced chemical equation tells us two things: 1. Which substances begin with (reactants) and end with (products) during the rearrangement process. 2. The ratio of particles involved. This ratio can be seen either as a ratio of individual particles OR as a ratio of moles. In the lab it is only practical to work with moles of substances rather than individual atoms or molecules, and so we interpret our equations as a ratio of moles, or a mole ratio. Example: 2 Mg + 1O2 → 2 MgO means for every 2 moles of Mg burned, 1 mole of O2 is required to produce 2 moles of MgO, or a ratio of 2 moles Mg : 1 mole O2 : 2 moles MgO We can use this mole ratio relationship to make predictions about how much we need of something, or how much we can make from what we have. Making Predictions In every reaction, there are three stages we need to consider to make good predictions: 1. Before: What we have before the reaction takes place. 2. Change: How much of each substance is formed (products) or rearranged (reactants) 3. After: How much of each substance is present after the reaction is complete. (difference between the Before and the Change) Some good organization can help us in making good predictions. -
Stoichiometry's PCK of University Chemistry Professors Abstract Keywords -...DR ANDONI GARRITZ RUIZ
Stoichiometry’s PCK of University Chemistry Professors Kira Padilla and Andoni Garritz Facultad de Química, Universidad Nacional Autónoma de México Ciudad Universitaria, Avenida Universidad 3000 04510 México, Distrito Federal, México Phone: (5255) 56223711 Fax: (5255) 56223439 Emails: [email protected]; [email protected] Abstract The purpose of this paper is to document the Pedagogical Content Knowledge (PCK) for a set of four university chemistry professors teaching Stoichiometry; i.e. the study of the mass and amount of substance ratios between two or more substances undergoing a chemical change or, in brief, ‘the science of chemical calculations’. This topic can be taught with a simple algorithmic purpose (going for immediate procedures without much understanding about what to do and/or why doing it) or it can be used to reinforce crucial concepts on the chemical reaction or even the particulate constitution of matter. A discussion is presented on the approach given by these four professors in their General Chemistry classes, which has been classified as Conceptual, Representational, Contextual and Procedural. Results are conclusive on the various pedagogical focuses on three of the approaches (Representational, Contextual and Procedural), and the equivalence of the four professors Conceptual approach. Results also reveal a link between Conceptual and Procedural knowledge. Keywords Pedagogical content knowledge, Content Representation, Conceptual profile zones, Stoichiometry, University level Introduction Shulman (1986, 1987) introduced the term pedagogical content knowledge (PCK) in order to draw attention to the value of the special amalgam of content and pedagogical knowledge that a teacher needs to be an outstanding one. Stoichiometry is a specific topic of the College General Chemistry course which PCK deserves to be documented and commented, as it has been pointed out by De Jong, Veal & Van Driel (2002). -
Development of Health-Based Alternative to the Total Petroleum Hydrocarbon (Tph) Parameter
INTERIM FINAL PETROLEUM REPORT: DEVELOPMENT OF HEALTH-BASED ALTERNATIVE TO THE TOTAL PETROLEUM HYDROCARBON (TPH) PARAMETER Prepared for: Bureau of Waste Site Cleanup Massachusetts Department of Environmental Protection Boston, MA Prepared by: Office of Research and Standards Massachusetts Department of Environmental Protection Boston, MA and ABB Environmental Services, Inc. Wakefield, MA AUGUST 1994 INTERIM FINAL PETROLEUM REPORT: DEVELOPMENT OF HEALTH-BASED ALTERNATIVE TO THE TOTAL PETROLEUM HYDROCARBON (TPH) PARAMETER TABLE OF CONTENTS Section Title Page No. EXECUTIVE SUMMARY .................................................................................................. v AUTHORS AND REVIEWERS .......................................................................................... ix 1.0 INTRODUCTION.......................................................................................................1-1 1.1 Background ...............................................................................................1-1 1.2 Purpose......................................................................................................1-2 1.3 Approach ...................................................................................................1-6 2.0 HAZARD IDENTIFICATION FOR PETROLEUM HYDROCARBONS.....................2-1 2.1 Composition of Petroleum Products...........................................................2-1 2.2 Toxic Effects of Whole Products................................................................2-5 2.2.1 Gasoline.........................................................................................2-5 -
2. Alkanes and Cycloalkanes
BOOKS 1) Organic Chemistry Structure and Function, K. Peter C. Vollhardt, Neil Schore, 6th Edition 2) Organic Chemistry, T. W. Graham Solomons, Craig B. Fryhle 3) Organic Chemistry: A Short Course, H. Hart, L. E. Craine, D. J. Hart, C. M. Hadad, 4) Organic Chemistry: A Brief Course, R. C. Atkins, F.A. Carey Hazırlayanlar : Prof. Dr. Pervin Ünal Civcir ve Doç. Dr. Melike Kalkan 2. ALKANES AND CYCLOALKANES 2.1 Nomenclature of alkanes 2.2 Physical Properties of Alkanes 2.3 Preparation of Alkanes 2.3.1 Hydrogenation of Alkenes and Alkynes 2.3.2 Alkanes From Alkyl Halides 2.3.2.1 Reduction 2.3.2.2 Wurtz Reaction 2.3.2.3 Hydrolysis of Grignard Reagent 2.3.3 Reduction of Carbonyl Compounds 2.3.3.1 Clemmensen Reduction 2.3.3.2 Wolf- Kıschner Reduction 2.3.3.3 Alkanes from Carboxylic Acids 2.4 Reactions of Alkanes 2.4.1 Radicalic substitution reactions 2.4.2 Combustion Reactions 2.4.3 Nitration 2.4.4 Cracking 2.5 Cycloalkanes 2.5.1 Nomenclature of Cycloalkanes 2.5.2 Conformations of Cycloalkanes 2.5.3 Substituted Cycloalkanes 2.5.3.1 Monosubstitued Cycloalkanes 2.5.3.2 Disubstitued Cycloalkanes Hazırlayanlar : Prof. Dr. Pervin Ünal Civcir ve Doç. Dr. Melike Kalkan 2.1 Nomenclature of Alkanes Alkanes with increasing numbers of carbon atoms have names are based on the Latin word for the number of carbon atoms in the chain of each molecule. Nomenclature of Straight Chain Alkanes: n CnH2n+2 n-Alkane n CnH2n+2 n-Alkane n CnH2n+2 n-Alkane 1 CH4 methane 6 C6H14 hexane 11 C11H24 undecane 2 C2H6 ethane 7 C7H16 heptane 12 C12H26 dodecane 3 C3H8 propane 8 C8H18 octane 13 C13H28 tridecane 4 C4H10 butane 9 C9H20 nonane 14 C14H30 tetradecane 5 C5H12 pentane 10 C10H22 decane 15 C15H32 pentadecane 2.2 Physical Properties of Alkanes (i) The first four alkanes are gases at room temperature. -
(C2–C8) Sources and Sinks Around the Arabian Peninsula
Atmos. Chem. Phys., 19, 7209–7232, 2019 https://doi.org/10.5194/acp-19-7209-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Non-methane hydrocarbon (C2–C8) sources and sinks around the Arabian Peninsula Efstratios Bourtsoukidis1, Lisa Ernle1, John N. Crowley1, Jos Lelieveld1, Jean-Daniel Paris2, Andrea Pozzer1, David Walter3, and Jonathan Williams1 1Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz 55128, Germany 2Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ, UMR8212, IPSL, Gif-sur-Yvette, France 3Department of Multiphase Chemistry, Max Planck Institute for Chemistry, Mainz 55128, Germany Correspondence: Efstratios Bourtsoukidis ([email protected]) Received: 29 January 2019 – Discussion started: 14 February 2019 Revised: 25 April 2019 – Accepted: 29 April 2019 – Published: 29 May 2019 Abstract. Atmospheric non-methane hydrocarbons source-dominated areas of the Arabian Gulf (bAG D 0:16) (NMHCs) have been extensively studied around the and along the northern part of the Red Sea (bRSN D 0:22), but globe due to their importance to atmospheric chemistry stronger dependencies are found in unpolluted regions such and their utility in emission source and chemical sink as the Gulf of Aden (bGA D 0:58) and the Mediterranean Sea identification. This study reports on shipborne NMHC (bMS D 0:48). NMHC oxidative pair analysis indicated that measurements made around the Arabian Peninsula during OH chemistry dominates the oxidation of hydrocarbons in the AQABA (Air Quality and climate change in the Arabian the region, but along the Red Sea and the Arabian Gulf the BAsin) ship campaign.