DOCSLIB.ORG

Take Home U2 Reactions.Pub

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Take Home U2 Reactions.Pub ts In a chemical reaction, there is a ncep change in the way atoms and Find these Co molecules combine. Signs of a chemical Words to Know reaction include: color or temperature in the word search below. change, or the production of light, electricity, or a new material. matter - anything that fills space and has mass ACID INDICATOR W ATOM ION atom - a very, very small particle that makes up all BASE LIGHT o matter BUBBLES MATTER r molecule - a small particle made of two or more CHEMICAL BOND MIXTURE d connected atoms CONCENTRATION MOLECULE CheM LaB ion - an atom or molecule with an electrical charge ELECTRON OMSI s electron - a negatively charged part of an atom ENDOTHERMIC REACTION chemical bond - formed when electrons are EQUILIBRIUM SOLUTION Take-Home Activities transferred or shared between two atoms EXOTHERMIC TEMPERATURE t chemical reaction - an interaction of atoms or o molecules to form new elements or molecules exothermic reaction - a chemical reaction that I E M E E L T W M K G W E C O gives off heat and that may feel hot S L B I S L O Q A U O V U I E k endothermic reaction - a chemical reaction that M E U T X A U J T A C I D M X n absorbs heat and that may feel cold O C B G H T B C T X H U F R O mixture - two or more materials that are mixed I T B N S G U Y E M X K A E T o together but not chemically bonded w solution - a completely uniform mixture Q R L A E J I R R L S T I H H concentration - the relative amount of a particular F O E A S L D L E F O O X T E atom or molecule in a solution. A large amount is W N S K G E G A A M M M N O R a high concentration; a small amount is a low C O N C E N T R A T I O N D M concentration M F E Q U I L I B R I U M N I acid - a compound that increases the number of I N D I C A T O R T C M K E C hydrogen ions (H+) in solution with water. All S O L U T I O N C B C A E D M acids have a pH below 7. B O N D N O B L A C I M E H C base - a compound that decreases the number of H O R N G C E I O N I M E Q C Chemical hydrogen ions (H+) in solution with water. All bases have a pH above 7. E R U T A R E P M E T V H K G pH - a scale that measures relative acidity and basicity Reactions indicator - a chemical that changes color with changes in pH. equilibrium - a point reached during a chemical reaction when no further changes occur This project funded by © 2006 OMSI Cloudy Globs Glow Fast, Glow Slow Gas Production Can you make a white gel from two clear liquids? Alter the rate of a reaction! Blow up a balloon! Materials: Materials: Materials: two small jars or glasses (about 4-oz) two clear glasses or jars baking soda warm water water tablespoon alum (in the spice aisle at grocery stores) ice one plastic bottle (1 liter or 20 ounces) 1/2 teaspoon measure two identical “lightsticks” small cup 1 teaspoon measure a dark room or area vinegar ammonia funnel To do and notice: one large balloon (8” or 9” size) To do and notice: 1. Run hot water from the faucet until it is quite hot. To do and notice: 1. Fill one jar half full with warm water. (Caution: be careful not to burn yourself.) Fill one glass 1. Measure 2 tablespoons of baking soda. Pour with the hot water. the baking soda into the plastic bottle. 2. Add ½ teaspoon alum. Stir or shake to mix the water and • What does the baking soda look like? alum completely. 2. Fill the other glass with ice and water. 2. Rinse and dry the tablespoon. Measure 3 3. To the other jar, add 2 teaspoons ammonia. tablespoons vinegar. Pour the vinegar into • What do the solutions look like in each jar? 3. Activate both lightsticks by the small cup. • Are the solutions clear or cloudy? bending them until they snap and • What does the vinegar look like? ammonia then shaking them. 4. Pour the ammonia into the jar with • What do you observe? 3. Using the funnel, pour the vinegar into the balloon. water and alum. • What happens? 4. Put one lightstick in each jar. 4. Attach the lip of the balloon onto the mouth of the bottle. Be careful not to spill the vinegar. 5. Allow the jar with the new mixture to 5. Turn out the lights or take the jars to a dark room or lift sit for a while. closet. 5. After the balloon is attached, lift the • What do you see at the bottom of • Which lightstick is glowing brighter? water and alum balloon to dump the vinegar into the bottle. the jar? • Which lightstick glows longer? • What do you hear? • What do you see? A closer look: A closer look: • What is happening to the balloon? Alum dissolves in water to make a clear solution. Energy transfer is part of all chemical reactions. The Ammonia (NH ) reacts with water to make a clear A closer look: 3 reaction in lightsticks releases energy in the form of light. solution of ammonium hydroxide (NH OH), or household When you mix vinegar and baking soda, their molecules 4 This process is called “chemiluminescence.” ammonia. When you mix these two clear solutions interact and make new substances. together, they react to form a new compound. A temperature change can cause a chemical reaction to go Baking soda, also called sodium bicarbonate, has the faster or slower. Heat speeds the rate of the chemical Alum contains aluminum When alum reacts with ammonia, formula NaHCO3. Vinegar, also called acetic acid, has reaction, so the lightstick in hot water is brighter. Cold aluminum hydroxide (Al(OH) ) is formed as a product of the formula CH3COOH. When they recombine they 3 slows the rate of the reaction, so the cold lightstick’s the reaction. Aluminum hydroxide does not dissolve in make sodium acetate (NaCH3COO), water (H2O), and supply of chemicals lasts longer. (Depending on the brand water and forms cloudy white globs. As the globs settle, carbon dioxide (CO2). you use, they may last 20 minutes to several hours.) they form a solid gel at the bottom of the jar. Carbon dioxide is the gas that creates bubbles inside © 2006 OMSI the bottle and inflates the balloon. .
Load more

Recommended publications
  • Synthesis of Alum from Aluminum
    Synthesis of Alum from Aluminum Taken from Central Oregon College Chemistry Manual OBJECTIVES: To carry out a series of reactions to transform a piece of aluminum foil into crystals of alum and to gain familiarity with using stoichiometry to determine the yield for the reaction. SAFETY AND DISPOSAL: Strong acids and bases are corrosive and should be handled with care. Immediately wipe up any spills and wash hands with plenty of soap and water. Work in the mini-hoods whenever possible to avoid breathing in fumes. All solutions can be disposed of down the sink with running water. The alum can be safely disposed of in the trash but has a number of uses and can be used for other laboratories, place alum crystals into the designated container. INTRODUCTION: Aluminum is a material that you may have had some experience with and paid little attention to, but has some very interesting characteristics. Here are some fun facts about aluminum metal: 1. Aluminum is the third most abundant element in the earth's crust. 2. The supply of aluminum ore is not inexhaustible. 3. The winning, or extraction of the metallic form an impure ionic source, of aluminum from aluminum ore is very costly from an energy point of view. 4. The above point explains why Napoleon III used aluminum dinnerware for his state dinners. Lesser guests were served on plates of gold or silver. 5. The process of obtaining pure metallic aluminum from aluminum oxide in a reasonably energy efficient manner, which made it possible for aluminum to be the inexpensive metal we know today, was developed in a home laboratory shortly after the chemist finished his undergraduate degree.
    [Show full text]
  • Uilitgd States Patent [19] [11] Patent Number: 4,647,386 Jamison [45] Date of Patent: Mar
    UIlItGd States Patent [19] [11] Patent Number: 4,647,386 Jamison [45] Date of Patent: Mar. 3, 1987 [54] INTERCALATED TRANSITION METAL Attorney, Agent, or Firm-—Robert E. Harris BASED SOLID LUBRICATING COMPOSITION AND METHOD OF SO [57] ABSTRACT , FORMING A solid lubricating composition and method for form ing such a composition are disclosed. The composition [76] Inventor: Warren E. Jamison, 528 Parkview Ave., Golden, Colo. 80401 is formed by intercalating a transition metal that has been chemically reacted with chalcogen to form a lay [21] App]. No.: 538,137 ered structure. The transition metal is selected from [22] Filed: Oct. 3, 1983 niobium, tantalum, tungsten and/or an alloy including one or more, and the transition metal is chemically [51] Int. Cl.4 ......................................... .. C10M 125/22 combined with chalcogen selected from sulfur, sele [52] US. Cl. ...................... .. 252/25; 423/561 R nium and/or a combination which can also include [5 8] Field of Search ..................... .. 252/25; 423/561 R tellurium to form a layered transition metal dischal [56] References Cited cogenide prior to intercalation with a metal, preferably U.S. PATENT DOCUMENTS a coinage metal. The effect of intercalation is to expand the crystal lattice to create a composition having excel 3,573,204 3/1971 Van Wyk ............................ .. 252/12 Thompson 252/12 lent lubricating characteristics the performance of 3,763,043 10/1973 which is not adversely effected by operation in a high 3,769,210 10/1973 Cais et a1. ........ .. 252/25 4,040,917 8/1977 Whittingham . .. 204/36 temperature environment. 4,094,893 6/ 1978 Dines .................................
    [Show full text]
  • Synergy of Alum and Chlorine Dioxide for Curbing Disinfection Byproduct Formation Potential at Central Arkansas Water Corey W
    University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 5-2012 Synergy of Alum and Chlorine Dioxide for Curbing Disinfection Byproduct Formation Potential at Central Arkansas Water Corey W. Granderson University of Arkansas, Fayetteville Follow this and additional works at: http://scholarworks.uark.edu/etd Part of the Environmental Engineering Commons, and the Water Resource Management Commons Recommended Citation Granderson, Corey W., "Synergy of Alum and Chlorine Dioxide for Curbing Disinfection Byproduct Formation Potential at Central Arkansas Water" (2012). Theses and Dissertations. 310. http://scholarworks.uark.edu/etd/310 This Thesis is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected], [email protected]. SYNERGY OF ALUM AND CHLORINE DIOXIDE FOR CURBING DISINFECTION BYPRODUCT FORMATION POTENTIAL AT CENTRAL ARKANSAS WATER SYNERGY OF ALUM AND CHLORINE DIOXIDE FOR CURBING DISINFECTION BYPRODUCT FORMATION POTENTIAL AT CENTRAL ARKANSAS WATER A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering By Corey W. Granderson University of Arkansas Bachelor of Science in Civil Engineering, 2008 May 2012 University of Arkansas Abstract Central Arkansas Water (CAW), the water utility for Little Rock, AR, draws their source water from Lake Maumelle and Lake Winona. To curb disinfection byproduct (DBP) formation, CAW has begun retrofitting their two plants to use chlorine dioxide as an alternative primary disinfectant followed by free chlorine secondary disinfection in the distribution system. In this study, fluorescence parallel factor (PARAFAC) analysis was combined with free chlorine simulated distribution system (SDS) tests and DBP formation potential (DBPFP) tests to study the benefit of chlorine dioxide primary disinfection (CDPD) with alum coagulation.
    [Show full text]
  • Aluminum Discovered: H.C. Oersted in 1825 Name: from Alum, Used By
    Aluminum Discovered: H.C. Oersted in 1825 Name: From alum, used by ancient Greeks and Romans as an astringent and as a mordant in dyeing. Sir Humphrey Davy proposed the name aluminum, but changed it to aluminium to have it conform to the spelling of other metals. This spelling was used in the U.S. until 1925 when the ACS when back to the original spelling. The rest of the world uses the “-ium” ending. Occurrence: It is the most common metallic element in the Earth's crust and occurs in many different forms in nature some of which are: bauxite, cryolite (Na3AlF6), micas, feldspars, vermiculite, diaspore (AlO2H), gibbsite (Al(OH)3), garnet (Ca3Al2(SiO4)3), beryl (Be3Al2Si6O18), turquoise (Al2(OH)3PO4H2O/Cu), corundum (-Al2O3), other Al2O3 with impurities are ruby (Cr(III)), topaz (Fe(III)), sapphire, and oriental emerald. Bauxite deposits are common. Large reserves are found in Australia, Africa, Brazil, Central America, Guinea, and Jamaica. Isolation: Bauxite (AlO2H•nH2O) is dissolved in molten NaOH (1200 ºC) and is precipitated with CO2, then dissolved in cryolite at 950 ºC and electrolyzed (Bayer process). Cost of 1 gram, 1 mole: $0.08, $2.20 Natural Isotopes: 27Al (100%) Physical and Relatively low melting point Chemical High electrical conductivity Properties: Soft Low density Silvery white in color Non-magnetic Corrosion resistant Highly malleable and ductile Reactions: 2 Al + 6 HCl 2 AlCl3 + 3 H2 2 Al(OH)3 Al2O3 + 3 H2O Uses: Alloys for building construction, transportation, containers and packaging, electrical power lines, cookware, etc. Al3.6Zr(OH)11.6Cl3.2•xH2O•glycine is the active ingredient in some antiperspirants Al2O3 is a major component of Portland cement Beryllium Discovered: By L.-N.
    [Show full text]
  • 6. Water Treatment 71 6
    6. WATER TREATMENT 71 6. Water treatment 6.1 Introduction Water can be contaminated by the following agents: ■ Pathogens – disease-causing organisms that include bacteria, amoebas and viruses, as well as the eggs and larvae of parasitic worms. ■ Harmful chemicals from human activities (industrial wastes, pesticides, fertilizers). ■ Chemicals and minerals from the natural environment, such as arsenic, common salt and fluorides. Some non-harmful contaminants may influence the taste, smell, colour or temperature of water, and make it unacceptable to the community. Water from surface sources is often contaminated by microbes, whereas groundwater is normally safer, but even groundwater can be contaminated by harmful chemicals from human activities or from the natural environment. Rainwater captured by a rooftop har- vesting system or with small catchment dams is relatively safe, provided that the first water is allowed to flow to waste when the rainy season starts. The amount of water to be treated should also be assessed. This can be estimated by assuming that each person will need a minimum of 20–50 litres of water a day for drinking, cooking, laundry and per- sonal hygiene. A community should be consulted when choosing a water-treatment system and should be made aware of the costs associated with the technology. In particular, community members should be made aware of the behavioural and/or cultural changes needed to make the system effective over the long-term and thus be acceptable to them. Communi- ties may also need to be educated about protecting water sources from animal or human contamination, and mobilized. It should be emphasized that all the positive effects of a water-treatment system could be jeopardized if the water is not drawn, stored and trans- ported carefully and hygienically.
    [Show full text]
  • Ecotoxicological Review of Alum Applications to the Rotorua Lakes
    Ecotoxicological Review of Alum Applications to the Rotorua Lakes ERI Report Number 52 Client report prepared for Bay of Plenty Regional Council By Grant Tempero Environmental Research Institute Faculty of Science and Engineering University of Waikato, Private Bag 3105 Hamilton 3240, New Zealand Cite report as: Tempero, G.W. 2015. Ecotoxicological Review of Alum Applications to the Rotorua Lakes. ERI Report No. 52. Client report prepared for Bay of Plenty Regional Council. Environmental Research Institute, Faculty of Science and Engineering, University of Waikato, Hamilton, New Zealand. 37 pp. Disclaimer: The information and opinions provided in the Report have been prepared for the Client and its specified purposes. Accordingly, any person other than the Client, uses the information and opinions in this report entirely at their own risk. The Report has been provided in good faith and on the basis that reasonable endeavours have been made to be accurate and not misleading and to exercise reasonable care, skill and judgment in providing such information and opinions. Neither The University of Waikato, nor any of its employees, officers, contractors, agents or other persons acting on its behalf or under its control accepts any responsibility or liability to third parties in respect of any information or opinions provided in this Report. Reviewed by: Approved for release by: Nick Ling John Tyrrell Associate Professor Research Developer Environmental Research Institute Environmental Research Institute University of Waikato University of Waikato Page | II Lay Summary Alum dosing is a highly effective method for removing phosphorus from freshwater systems, and is currently being employed by the Bay of Plenty Regional Council to help meet water quality targets for lakes Rotorua, Rotoehu and Okaro.
    [Show full text]
  • Toxicological Profile for Aluminum
    ALUMINUM 145 4. CHEMICAL AND PHYSICAL INFORMATION 4.1 CHEMICAL IDENTITY Aluminum is a naturally occurring element that appears in the second row of Group 13 (IIIA) of the periodic table (O’Neil et al. 2001). Table 4-1 lists common synonyms and other pertinent identification information for aluminum and selected aluminum compounds. 4.2 PHYSICAL AND CHEMICAL PROPERTIES Aluminum is a silvery-white, malleable, and ductile metal. In moist air, a protective oxide coating of aluminum oxide is formed on its surface. In compounds, aluminum typically occurs in its +3 oxidation state (Lide 2005; O’Neil et al. 2001). Table 4-2 lists important physical and chemical properties of aluminum and selected aluminum compounds. ALUMINUM 146 4. CHEMICAL AND PHYSICAL INFORMATION a Table 4-1. Chemical Identity of Aluminum and Compounds Characteristic Information Chemical name Aluminum Aluminum chloride Aluminum chlorohydrate (anhydrous) Synonym(s) Aluminiumb; alumina fibre; Aluminum trichloride; Aluminol ACH; aluminum metana; aluminium aluminum chloride chloride hydroxide oxide, bronze; aluminum (1:3); Pearsall basic; aluminum chloride dehydrated; aluminium oxide; aluminum oxychloride; flake; aluminum powder; PAC 250A; Astringen; aluminum-27; Noral Chlorhydrol; Locron aluminum; PAP-1 d Chemical formula Al AlCl3 Unspecified 3+ - Chemical structure Al Al (Cl )3 Unspecified Identification numbers: CAS registry 7429-90-5 7446-70-0 1327-41-9 EINECS 231-072-3 231-208-1 215-477-2 NIOSH RTECS BD330000 BD0525000 No data EPA hazardous waste No data D003 No data code EPA Pesticide 000111 013901 No data Chemical Code DOT/UN/NA/IMCO UN 1309; UN 1396; IMO UN 1726; UN 2581; No data shipping 4.1; IMO 4.3; NA 9260 IMO 8.0 HSDB 507 607 No data ALUMINUM 147 4.
    [Show full text]
  • Preparation and Properties of Chalcogenide Glasses In
    PREPARATION AND PROPERTIES OF CHALCOGENIDE GLASSES IN As-Ge-S AND As-Ge-Se SYSTEMS A THESIS Presented to The Faculty of the Division of Graduate Studies and Research By Yogesh Mehrotra In Partial Fulfillment of the Requirements for the Degree Master of Science in Ceramic Engineering Georgia Institute of Technology June 1976 PREPARATION AND PROPERTIES OF CIIALCOGENIDE GLASSES IN As-Ge~S AND As-Ge-Se SYSTEMS Approved: Jq4eph if. Pentecost,- Chairman Willr" " " ' Airamrr cirapman~ 7 Date approved by Chairman>^y,..ixt»>/ Tj '>Tw ii ACKNOINTLEDGMENTS I wish to express my profound gratitude to Dr. J. L. Pentecost for his encouragement, guidance, advice, and patience during this invest­ igation. I also wish to thank Drs. W. E. Moody and A. T. Chapman for their suggestions while serving on the reading committee and Dr. J. K. Cochran for his interest and assistance in this project. A special word of thanks is also due to Mr. Thomas Macrovitch for his assistance in the experimental work. My appreciation is also expressed to Mr. Donald E. Lillie of the Glass Blowing Laboratory and to Dr. Earl Meeks and Messrs. Gerald Hill, James J. Gallagher, and Barry McManus of the Engineering Experiment Station for their valuable assistance in conducting various experiments. My profound thanks are due to Ms. Kathy D. Browning whose inspira­ tion helped me overcome many difficult moments in this investigation and to Ms. Betty Yarborough for her excellent typing. lil TABLE OF CONTENTS Page ACKNOWLEDGMENTS ii LIST OF TABLES v LIST OF ILLUSTRATIONS vii SUMMARY ix Chapter I. INTRODUCTION 1 II.
    [Show full text]
  • The Allure of Aluminium
    in your element The allure of aluminium Daniel Rabinovich outlines the history, properties and uses of aluminium — one of the most versatile, pervasive and inexpensive metals today, yet it was considered a rare and costly element only 150 years ago. t is hard to believe that aluminium was silver, which hampered the development a common Lewis acid, is extensively applied once more expensive than gold and that, of large-scale applications and motivated in Friedel–Crafts acylation and alkylation Iin the mid-nineteenth century, Napoleon the search for an alternative and more reactions, and aluminium chlorohydrate, III used silverware made of the light metal economical preparation process. Al2Cl(OH)5, is the active ingredient in when he really wanted to impress his guests It was only in 1886 that Charles M. Hall many antiperspirants. Large quantities at stately dinners. Even though element 13 in the US and Paul L. T. Héroult in France, of methylaluminoxane, a generic name is the most abundant metal in the Earth’s almost simultaneously and completely used to describe the ill-defined mixture of crust (~8%) and is present in more than independently, devised aluminium species obtained by partial hydrolysis of 270 different minerals, its high affinity for production processes that relied on the trimethylaluminium, are employed in the oxygen and the chemical stability of its electrolysis of alumina (Al2O3) dissolved Ziegler–Natta polymerization of olefins. oxides and silicates precluded its isolation in molten cryolite (Na3AlF6). An efficient The
    [Show full text]
  • Paramagnetism of Caesium Titanium Alum Lucjan Dubicki and Mark J
    Paramagnetism of caesium titanium alum Lucjan Dubicki and Mark J. Riley Citation: The Journal of Chemical Physics 106, 1669 (1997); doi: 10.1063/1.473320 View online: http://dx.doi.org/10.1063/1.473320 View Table of Contents: http://scitation.aip.org/content/aip/journal/jcp/106/5?ver=pdfcov Published by the AIP Publishing Articles you may be interested in Ab initio study of dynamical E × e Jahn-Teller and spin-orbit coupling effects in the transition-metal trifluorides TiF3, CrF3, and NiF3 J. Chem. Phys. 136, 084308 (2012); 10.1063/1.3687001 Multiple lines of conical intersections and nondegenerate ground state in T⊗t 2 Jahn–Teller systems J. Chem. Phys. 112, 8470 (2000); 10.1063/1.481449 Crystal-field splitting, magnetic interaction, and vibronic excitations of 244 Cm 3+ in YPO 4 and LuPO 4 J. Chem. Phys. 109, 6800 (1998); 10.1063/1.477326 Giant second-order Zeeman effect in titanium (III) doped caesium gallium alum J. Chem. Phys. 109, 2967 (1998); 10.1063/1.476885 Paramagnetism of caesium titanium alum and the Jahn–Teller interaction J. Chem. Phys. 107, 8275 (1997); 10.1063/1.475029 Reuse of AIP Publishing content is subject to the terms: https://publishing.aip.org/authors/rights-and-permissions. Downloaded to IP: 130.102.82.2 On: Tue, 18 Oct 2016 06:21:12 Paramagnetism of caesium titanium alum Lucjan Dubicki Research School of Chemistry, Australian National University, Canberra, 0200, Australia Mark J. Riley Department of Chemistry, University of Queensland, St Lucia, 4072, Australia ~Received 31 May 1996; accepted 16 October 1996! • Caesium titanium alum, CsTi~SO4!2 12H2O, is a b alum and exhibits a large trigonal field and a 2 dynamic Jahn–Teller effect.
    [Show full text]
  • Aluminium Ammonium Sulfate
    ALUMINIUM AMMONIUM SULFATE Prepared at the 29th JECFA (1985), published in FNP 34 (1986) and in FNP 52 (1992). Metals and arsenic specifications revised at the 63rd JECFA (2004). A group PTWI of 7 mg/kg bw for aluminium and its salts was established at the 33rd JECFA (1988) SYNONYMS Ammonium alum; INS No. 523 DEFINITION Chemical names Aluminium ammonium sulphate C.A.S. number 7784-25-0 Chemical formula AlNH4(SO4)2 · 12H2O Formula weight 453.32 Assay Not less than 99.5% of AlNH4(SO4)2 · 12H2O DESCRIPTION Large, colourless crystals, white granules, or a powder; odourless FUNCTIONAL USES Buffer, neutralizing agent, colour fixative CHARACTERISTICS IDENTIFICATION Solubility Freely soluble in water; insoluble in ethanol Test for aluminium Passes test (Vol. 4) Test for ammonium Passes test (Vol. 4) Test for sulfate (Vol. 4) Passes test PURITY Alkalis and alkaline earths Completely precipitate the aluminium from a boiling solution of 1 g of (Vol. 4 for TS solutions) the sample in 100 ml of water by the addition of enough ammonia TS to render the solution distinctly alkaline to methyl red TS, and filter. Evaporate the filtrate to dryness, and ignite. The weight of the residue does not exceed 5 mg. Fluoride Not more than 30 mg/kg See description under TESTS Selenium (Vol. 4) Not more than 30 mg/kg Test 0.2 g of the sample as directed in the Limit Test (Method II) Lead Not more than 3 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.” TESTS Fluoride Lime suspension Carefully slake about 56 g of low fluoride calcium oxide (about 2 mg/kg F) with 250 ml of water, and add 250 ml of 60% perchloric acid slowly and with stirring.
    [Show full text]
  • Alum from Scrap Aluminum
    1 Experiment 4: Synthesis of Alum from Scrap Aluminum Objective: In this experiment, you will be converting the aluminum metal from a beverage can into the chemical compound potassium aluminum sulfate, KAl(SO4)2•12 H2O, commonly referred to as alum. Introduction It had been a good year for the O’Keefe farm with just the right amount of sun and rain. In fact, the cucumbers had grown so well that Richard was afraid he wouldn’t be able to sell them fast enough. Faced with the prospect of a warehouse full of rotten cukes, he contemplated the idea of preserving them and selling them as “O’Keefe’s Farm Fresh Pickles”. He discussed the plan with his wife, Diane, who agreed it was a good idea and said she had a delicious pickling recipe that had been handed down to her from her mother. “I recall one of the ingredients was alum. I think it helps to keep the pickles firm and crisp,“ Diane said. “It just so happens that I know of a recipe for making alum from aluminum cans,” Richard said. “We can use some of those soda pop cans that have been piling up, and that should save us some money.” “How can you convert aluminum metal into an aluminum salt?” Diane asked. Richard explained the chemistry behind the process: One of the interesting properties of aluminum is that it is amphoteric, meaning it will dissolve in both strong, aqueous acids and strong, aqueous bases (see Tro, pp 824-5). In both cases, the formation of hydrogen gas is observed: + 3+ 2 Al (s) + 6 H (aq) → 2 Al (aq) + 3 H2 (g) – – 2 Al (s) + 6 H2O (l) + 2 OH (aq) → 2 Al(OH)4 (aq) + 3 H2
    [Show full text]