DOCSLIB.ORG

Elephant Toothpaste Lab

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Elephant Toothpaste Lab Elephant Toothpaste Lab This is a guideline to help you write up a formal lab report. This is not to be used as the formals lab report. You do not have to turn this in. Purpose: To break down a compound and release the maximum amount of substance in an elemental form. Background: (Sample) Hydrogen peroxide is an extremely reactive substance with the symbol H2O2 (water is H2O). That extra oxygen atom makes hydrogen peroxide a powerful oxidizer and it is widely used in strong concentrations as an industrial bleaching agent. It is corrosive to human skin in concentrations above 8% but very useful as an antiseptic at lower concentrations such as 3%. Hydrogen peroxide readily decomposes into water (H2O) and oxygen gas (O2) in the presence of even trace amounts of a proper catalyst. Catalysts are chemicals that increase the rate of a reaction. It this case, the catalyst is being used to increase the rate of breakdown of H2O2. Just a few grams of the catalyst potassium iodide (KI) causes nearly all of the hydrogen peroxide in a 30% solution to rapidly decompose. Significant quantities of heat and oxygen gas are released during decomposition making this an exothermic (heat releasing) reaction that should be handled with care. A squirt of detergent lowers the solutions surface tension so that the oxygen produced forms tiny bubbles which combine to make a very large volume of foam. Add something about the strength of catalysts. You will need to look this up before coming to class. Question: Which catalyst concentration will supply the most oxygen, 2M or saturated potassium iodide solution? Hypothesis: I hypothesize _______________________________________________________ because _____________________________________________________________________________. Materials: • 20 ml Hydrogen peroxide (30%) - This is ten times stronger than the normal hydrogen peroxide you can find at the store • 5ml potassium iodide solution, 2 M and saturated potassium iodide • 5ml Liquid soap (a small squirt will do) • 5 drops Liquid Food coloring running down the side of the graduated cylinder • Erlenmeyer flask about 250ml or graduated cylinder 200- 500ml in size • Lighter • Splints • timers • Safety glasses • Rubber gloves for clean-up Methods 1. Measure 20 mL of the 30% hydrogen peroxide into the Erlenmeyer flask or cylinder. It's best to place the cylinder in a large tray to make the clean-up as easy as possible. 2. Add a squirt (that's a technical term meaning about 5 mL) of dish soap to the graduated cylinder containing the 30% hydrogen peroxide. 3. Add a few drops (approximately 5 drops) of food coloring run down the sides of the cylinder to spice things up. 4. Add 5 mL of the 2M sodium iodide solution (2M refers to the molarity which is a concentration of the solution). The reaction takes place quickly, so it's important to stand back. 5. Determine how you will measure how much oxygen is present. Write it here. ( Hint - How can you detect whether or not you generated oxygen gas with this reaction?) 6. Use all possible observation skills to record what happens. Safety Precautions: Results: 1) Write a short paragraph describing what happened during this experience. This is the place to put your observations. ONLY include facts. DO NOT include an interpretation of the facts. Interpretation means describing why something happened. Include a table to illustrate the results you got from the different concentrations of KI. Discussion: This is where you interpret your experiment. These are guide questions. Use the checklist for your lab reports. Sample first sentence: This research demonstrated more oxygen was generated by ………. What reaction occurred during this experiment? Which of these products is in its elemental form? Why did this reaction occur and what made it occur so rapidly? What did you learn from this experiment? How did you control the variables in this experiment so that you know your results are just the result of testing the one independent variable you intended to change?. Conclusion: My hypothesis is (accepted or rejected) _________________________________________ because ___________________________________________________________________ __________________________________________________________________________. Practical application or Future research: Write a short paragraph about how the breakdown of hydrogen peroxide could be used by you personally or how knowledge of this process can benefit you or industry. (Yes, you will have to look this up). .
Load more

Recommended publications
  • 2-‐Bromobutane
    Practice Questions 1. What is true about the reaction between (R)-2-bromobutane and potassium cyanide as shown below? Br KCN a) The product is a racemic mixture. b) The product is (S)-2-cyanobutane. c) The mechanism proceeds through a stable intermediate. d) The mechanism proceeds through a single transition state step. e) Answers a and c. f) Answers b and d. 2. The following reaction goes through an SN2 mechanism. - - CH3CH2CH2Br + OH à CH3CH2CH2OH + Br At constant temperature, what is the effect on the rate of the reaction by simultaneously doubling the concentration of propyl bromide and OH- ion? a) It would increase the rate by six. b) It would double the rate. c) It would triple the rate. d) It would increase the rate by four. e) It would have no effect on the rate. 3. Which is the minor substitution product in the following reaction? a) I b) II c) III d) Equal amounts of I and II e) None of these products 4. What is the major product of the following reaction? a) I b) II c) III d) IV e) Equal amount of I and III 5. Consider the reaction between 2-bromo-2,4-dimethylpentane and sodium iodide, NaI, in acetone. Br NaI I acetone At constant temperature, what is the effect on the reaction rate if one simultaneously double the concentration of 2-bromo-2,4-dimethylpentane and sodium iodide? a) It would double the reaction rate. b) It would triple the reaction rate. c) It would quadruple the reaction rate. d) It would increase the reaction rate by 5.
    [Show full text]
  • Sodium Iodide Spotlight 352 Compiled by Vinícius Rangel Campos Vinícius Rangel Campos Was Born in Niterói/RJ, Brazil in 1986
    1186 SPOTLIGHT SYNLETT Sodium Iodide Spotlight 352 Compiled by Vinícius Rangel Campos Vinícius Rangel Campos was born in Niterói/RJ, Brazil in 1986. He This feature focuses on a re- received his Chemistry degree from the Universidade Federal Fluminense (UFF), Niterói/RJ, Brazil in 2009. He is currently in the agent chosen by a postgradu- final stages of his MSc. studies under the supervision of Professors ate, highlighting the uses and Anna Claudia Cunha and Vitor Francisco Ferreira in Organic preparation of the reagent in Chemistry at the Universidade Federal Fluminense. His research in- current research terest is focused on the design and synthesis of new bioactive com- pounds, such as quinone and 1,2,3-triazole derivatives. Instituto de Química, Universidade Federal Fluminense, UFF, CEP: 24020-141 Niterói, Rio de Janeiro, Brazil E-mail: [email protected] Introduction NaI R–I NaX + R–X acetone Sodium iodide (NaI) occurs as colorless, odorless or as a X = Cl or Br white crystalline solid; it is slightly hygroscopic, and a commercially available reagent. It is soluble in water, Scheme 1 alcohols, acetone, and other organic solvents and stable This reaction has been expanded to include the conversion under normal temperature and pressure (mp: 651 °C, of alcohols into alkyl halides by first converting the alco- d = 3.67 g/cm3).1 On a laboratory scale, sodium iodide hol into a sulfonate ester (tosylates or mesylates are usu- may be prepared by neutralizing a solution of sodium hy- ally used), and then performing the substitution.6 Other droxide or sodium carbonate with hydriodic acid.2 Sodi- applications using sodium iodide as reagent in organic um iodide is a very useful and versatile reagent for the synthesis have been reported.
    [Show full text]
  • Revision of KS4 the Periodic Table for KS5 Chemistry - Worksheet
    Revision of KS4 The Periodic Table for KS5 Chemistry - Worksheet 1. On the copy of the periodic table (next page) label the following: a. metals and non metals b. groups (with numbers) c. periods (with numbers) d. transition elements 2. How are elements in the periodic table ordered? 3. Find two examples where the mass number does not increase. 4. How many electrons does Magnesium have in its highest energy level? 5. How many electrons does Oxygen have in its highest energy level? 6. What do elements in the same group have in common? 7. What happens to reactivity in group 1 as you go down the group? 8. What happens to reactivity in group 7 as you go down the group? 9. Name 1 similarity and 1 difference between group 1&2 metals and the transition elements. 10. Write a word and symbol equation to show how sodium reacts with water. 11. If identical pieces of lithium and potassium were dropped into a bowl of water at the same time describe how their reactions would differ. 12. Complete the table with ticks to show which reaction will happen. Fluorine Chlorine Bromine Iodine Sodium fluoride Sodium chloride Sodium bromide Sodium iodide Extension Question Research the appearance and state of group 7 elements, use this knowledge to predict observation for the reaction in question 12. Revision of KS4 The Periodic Table for KS5 Chemistry Image credit to LeVanHan https://commons.wikimedia.org/wiki/File:Periodic-table.jpg Revision of KS4 The Periodic Table for KS5 Chemistry Revision of KS4 The Periodic Table for KS5 Chemistry - Worksheet (Answers) 1.
    [Show full text]
  • The Summer Assignment Will Receive a GRADE on the First Day of Class – August 9
    Bishop Moore AP Chemistry Summer Assignment June 2017 Future AP Chemistry Student, Welcome to AP Chemistry. In order to ensure the best start for everyone next fall, I have prepared a summer assignment that reviews basic chemistry concepts some of which you may have forgotten you learned. For those topics you need help with there are a multitude of tremendous chemistry resources available on the Internet. With access to hundreds of websites either in your home or at the local library, I am confident that you will have sufficient resources to prepare adequately for the fall semester. The reference text book as part of AP course is “Chemistry: The Central Science” by Brown LeMay 14th Edition for AP. Much of the material in this summer packet will be familiar to you. It will be important for everyone to come to class the first day prepared. While I review throughout the course, extensive remediation is not an option as we work towards our goal of being 100% prepared for the AP Exam in early May. There will be a test covering the basic concepts included in the summer packet during the first or second week of school. You may contact me by email: ([email protected]) this summer. I will do my best to answer your questions ASAP. I hope you are looking forward to an exciting year of chemistry. You are all certainly excellent students, and with plenty of motivation and hard work you should find AP Chemistry a successful and rewarding experience. Finally, I recommend that you spread out the summer assignment.
    [Show full text]
  • SN2 Reactions of Alkyl Halides
    SN 2 Reactions of Alkyl Halides OBJECTIVE To examine factors affecting the relative rates of the SN2 reaction of alkyl halides such as: • alkyl halide structure • nature of the leaving group • properties of the nucleophile • steric hindrance INTRODUCTION The alkyl halides play an important role in organic synthesis. They can be easily prepared from alcohols or alkenes, among other starting materials. They in turn can be used in the synthesis of a large number of functional groups. These syntheses are often carried out by nucleophilic substitution reactions in which the halide is replaced by some nucleophile. These substitution reactions can occur in one smooth step, or in two discrete steps, depending primarily on the structure of the alkyl group. These mechanisms are known as SN2 and SN1: In this laboratory period we will spend some time looking at SN2 reactions. To get started, let's propose a mechanism for the reaction: − − CH3Br + HO ! CH3OH + Br (1) • The rate of this reaction is directly proportional to the concentration of both methyl bromide and sodium hydroxide. − Rate = k[CH3Br][OH ] (2) • The reaction proceeds with inversion of configuration. Any ideas? This mechanism was initially elucidated by Sir Christopher Ingold and Edward Hughes, in the 1930s. They interpreted the second-order kinetic behavior to mean that the rate-determining step is a bimolecular, concerted process. δ− δ− − − HO + CH3Br ! HO − − CH3 − − Br ! CH3OH + Br (3) transition state c 2011-2013 Advanced Instructional Systems, Inc. and Maria Gallardo-Williams 1 Therefore the following mechanism was proposed | the backside attack of the nucleophile, with the leaving group leaving in a concerted step.
    [Show full text]
  • Chlorotrimethylsilane and Sodium Iodide
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Archive Ouverte en Sciences de l'Information et de la Communication Chlorotrimethylsilane and Sodium Iodide: A Remarkable Metal-Free Association for the Desulfurization of Benzylic Dithioketals under Mild Conditions Guangkuan Zhao, Ling-Zhi Yuan, Mouad Alami, Olivier Provot To cite this version: Guangkuan Zhao, Ling-Zhi Yuan, Mouad Alami, Olivier Provot. Chlorotrimethylsilane and Sodium Iodide: A Remarkable Metal-Free Association for the Desulfurization of Benzylic Dithioketals under Mild Conditions. Advanced Synthesis and Catalysis, Wiley-VCH Verlag, 2018, 360 (13), pp.2522-2536. 10.1002/adsc.201800437. hal-02394255 HAL Id: hal-02394255 https://hal.archives-ouvertes.fr/hal-02394255 Submitted on 4 Dec 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. FULL PAPER DOI: 10.1002/adsc.201((will be filled in by the editorial staff)) Chlorotrimethylsilane and Sodium Iodide: A Remarkable Metal- Free Association for the Desulfurization of Benzylic Dithioketals under Mild Conditions Guangkuan Zhao, Ling-Zhi Yuan, Mouad Alami* and Olivier Provot* BioCIS, Equipe Labellisée Ligue Contre le Cancer, Univ Paris-Sud, CNRS, University Paris Saclay, 92290, Châtenay- Malabry, France France Fax: (+33) 146-83-58-87, E-mail: [email protected] or [email protected] d: ((will be filled in by the editorial staff)) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.((Please delete if not appropriate)) Abstract.
    [Show full text]
  • Sodium Iodide, ACS Safety Data Sheet According to Federal Register / Vol
    Sodium Iodide, ACS Safety Data Sheet according to Federal Register / Vol. 77, No. 58 / Monday, March 26, 2012 / Rules and Regulations Date of issue: 05/05/2015 Revision date: 04/04/2018 Supersedes: 05/05/2015 Version: 1.1 SECTION 1: Identification 1.1. Identification Product form : Substance Substance name : Sodium Iodide, ACS CAS-No. : 7681-82-5 Product code : LC24645 Formula : NaI 1.2. Recommended use and restrictions on use Use of the substance/mixture : For laboratory and manufacturing use only. Recommended use : Laboratory chemicals Restrictions on use : Not for food, drug or household use 1.3. Supplier LabChem Inc Jackson's Pointe Commerce Park Building 1000, 1010 Jackson's Pointe Court Zelienople, PA 16063 - USA T 412-826-5230 - F 724-473-0647 [email protected] - www.labchem.com 1.4. Emergency telephone number Emergency number : CHEMTREC: 1-800-424-9300 or +1-703-741-5970 SECTION 2: Hazard(s) identification 2.1. Classification of the substance or mixture GHS-US classification Hazardous to the aquatic H400 Very toxic to aquatic life environment - Acute Hazard Category 1 Full text of H statements : see section 16 2.2. GHS Label elements, including precautionary statements GHS-US labeling Hazard pictograms (GHS-US) : GHS09 Signal word (GHS-US) : Warning Hazard statements (GHS-US) : H400 - Very toxic to aquatic life Precautionary statements (GHS-US) : P273 - Avoid release to the environment. P391 - Collect spillage. P501 - Dispose of contents/container to comply with local, state and federal regulations 2.3. Other hazards which do not result in classification Other hazards not contributing to the : None under normal conditions.
    [Show full text]
  • Nucleophilic Substitution Reactions of Organic Halides
    Exercise 10: Nucleophilic Substitution Reactions of Organic Halides Introduction: Substitution Reactions Substitution reactions are reactions where the two species involved exchange parts: Ex. Na C + Br C C + NaBr C There are two types of substitution reactions that commonly occur in organic chemical reactions, the SN2 and the SN1 reaction. They have different mechanisms which means their ability to occur is determined by factors like sterics around the alkyl halide, the choice of nucleophile used or even the solvent for the reaction. The SN2 Reaction (Substitution, Nucleophilic, Bimolecular) The SN2 type reaction is a one-step, concerted substitution process (make new bonds, break old bonds simultaneously). Both the alkyl halide and the nucleophile are involved (“bimolecular”) to determine the rate of reaction: Nuc X + X Nuc Factors that affect the SN2 Reaction: 1. Steric Congestion of Alkyl Halide -The more congested and sterically hindered the alkyl halide, the slower the reaction. Remember that alkyl halides have sp3 hybridized carbons, to which the halide is bonded. Fastest Slower Never CH3-X > RCH2-X > R2CH-X >>>>>>>>>>>>>>> R3C-X 2. The Leaving Group is what the halide is referred to in a substitution reaction and it is the group that must leave the alkyl halide. It is almost always expelled with a full negative charge in an SN2 reaction. The best leaving groups will be those that can best stabilize the anion (i.e. the weakest bases). Halides: I⊖ , Br⊖ > Cl⊖ >>> F⊖ (best) (worst) 3. The choice of solvent affects rate by affecting a reagent’s energy levels. Solvent molecules do what is called “solvation”, meaning they surround certain species in a reaction.
    [Show full text]
  • Synergistic Effects of Sodium Iodide and Sodium Dodecyl Sulfate at Low
    This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. pubs.acs.org/EF Article Synergistic Effects of Sodium Iodide and Sodium Dodecyl Sulfate at Low Concentrations on Promoting Gas Hydrate Nucleation Fariba Asadi, Ngoc N. Nguyen,* and Anh V. Nguyen* Cite This: Energy Fuels 2020, 34, 9971−9977 Read Online ACCESS Metrics & More Article Recommendations ABSTRACT: Surfactants and/or salts at low concentrations are inherently relevant to gas hydrate formation in nature and industry. However, the combined effects of surfactants and salts at low concentrations on gas hydrate formation are poorly understood. Here, we aim to fill this gap of knowledge by examining the effects of sodium dodecyl sulfate (SDS) and sodium iodide (NaI) at millimolar concentrations on methane hydrate formation. We show that adding NaI to dilute SDS solutions reduces the induction time significantly, promoting gas hydrate nucleation. Meanwhile, adding NaI adversely reduces the growth of methane hydrate. Fundamental studies based on sum frequency generation spectroscopy indicate an electrostatically aligned water layer at the gas− SDS solution interface caused by the charged interface as a result of surface adsorption of dodecyl sulfate anions. This aligned interfacial water layer hinders the nucleation of gas hydrate at the gas−SDS solution interface. Added NaI diminishes the alignment of interfacial water, thereby favoring the nucleation of the gas hydrate. Even though, the adverse (inhibiting) effect of added NaI on the methane hydrate growth remains a puzzling observation that requires further investigations.
    [Show full text]
  • Preparationbehaviorcertainhalo
    :O: UBRAR.YOF THE ' ' 00: ' °UNIVERSIlY OF MISSOURI . '. ~ . ..... .. '\ THE PREPARATION AND BEHAVIOR OF CERTAIN HALOGEN AND NITRO DERIVATIVES OF BEnZENE by Harry Fagan Yancey, A. B. 'II • • • 10 . ~ , " . - " .. .. .. ... .. ... ___..... .:J. .. ..:...;..: .. .:. .. ) . "" . ... .": ... ~ ... 10 ', ..... -. SUBMITTED IN PARTIAL FULFILLMENT OF THE RE­ QUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in the GRADUATE SCHOOL of the UNIVERSITY OF MISSOURI 1915 TABLE OF CONTENTS Page I Introduction 1- 4 II Experimental Part 5-18 1. Action of Sodium on Symmetrical Tribromo- trinitrobenzene. 5 2. Action of Sodium on l-Iodo-2.4,6-Tribromo- benBene. 5 3. Action of Sodium on Symmetrical Tribromo- iodobenzene and Ethyl Iodide. 8 4. Aotion of Sodium on Symmetrical Tribromo- benzene. 9 5. Prep'aration of l-Iodo-2,6-Dibromo-4-Ui- trobenzene. 10 6. Properties of 1-Iodo-2,6-Dibromo-4-Nitro- benzene. 11 7. Action of Sodium Ethylate on l-Iodo-2,6-Di- bromo-4-Nitrobenzene. 12 8. Preparation of l-Iodo-2,6-Dibromo-4,5-Dini- trobenzene. 13 9. Properties of l-Iodo-2,6-Dibromo-4,5-Dini- trobenzene. 13 10. Preparation of l-Chloro-2,6-Dibromo-4-Ni- trobenzene. 14 11. Action of Nitric Acid on 1-Iodo-2,4,6-Tri- bromobenzene. 17 12. Properties of l-Chloro-2,6-Dibromo-4-Nitro- benzene. 16 13. Preparation of l-Chloro-2,6-Dibromo-4,5-Di- nitrobenzene. 16 14. Properties of l-Ch1oro-2,6-Dibromo-4,5-Di- nitrobenzene. 16 III Discussion of Results 19-21 INTRODUCTION The common method for the preparation of diphenyl 1 and alkyl benzene derivatives is that of ~ittig.
    [Show full text]
  • Complete List of Chemicals These Chemicals Are Stored in an Adjacent Area
    Possible Hazards for FSCI - 210 Finger Print Dust (pulverized volcanic rock) Cyanoacrylate (super glue) Dried blood smears (human and canine) Hydrogen peroxide drops Ethyl alcohol drops Phenolphthalein drops Complete List of Chemicals These chemicals are stored in an adjacent area. Any could be used for another course in the same lab room as FSCI - 210 but at a different time. Exposure is possible but not probable. Acetanilide Ammonium Dichromate Acetic Acid, Glacial Ammonium Hydroxide Acetic Acid, 0.01M, 0.1M, 1M Ammonium Nitrate Acetic Anhydride Ammonium Nitrate, 0.1M Acetone Ammonium Oxalate Acrylic Acid Monohydrate Adhesive Side Powder, Dark Ammonium Persulfate Albumin, Egg Amyl Alcohol Alka-Seltzer Argon Spectrum Tubes All-Purpose Cleaner Arsenic Trioxide Aluminum (Foil) Ascorbic Acid (Vitamin C) Aluminum (Wire) Aspirin (Acetylsalicylic Acid) Aluminum Nitrate – 9-hydrate Barium Chloride-anhydrous Aminobenzoic Acid, 3- Barium Chloride-2-hydrate Ammonia (household) Barium Hydroxide – Anhydrous Ammonia Tablets #1, #2 Barium Hydroxide – 8-hydrate Ammonium Acetate Barium Nitrate Ammonium Acetate, 0.1M Basic Yellow Ammonium Bicarbonate Benzil Ammonium Chloride Benzoic Acid Benzophenone Copper(II) Nitrate–2½-hydrate Bleach Copper(II) Sulfate–Anhydrous Bogen Universal Indicator Copper(II) Sulfate–5-hydrate Boiling Chips, pumice Cyanoacrylate Cyclohexane Boric Acid Cyclohexanol Boric Acid, 0.1M Cyclohexanone Brass Cyclohexene Bromcresol Green Indicator Deet (N,N-diethyl-m-toluamide) Bromoethane (Ethyl Bromide) Dessicant Bromothymol Blue Dichlorobenzene-p
    [Show full text]
  • Method 360.2
    METHOD #: 360.2 Approved for NPDES (Issued 1971) TITLE: Oxygen, Dissolved (Modified Winkler, Full-Bottle Technique) ANALYTE: CAS # O Oxygen 7782-44-7 INSTRUMENTATION: Titration, Probe STORET No. 00300 1.0 Scope and Application 1.1 This method is applicable for use with most wastewaters and streams that contain nitrate nitrogen and not more than 1 mg/L of ferrous iron. Other reducing or oxidizing materials should be absent. If 1 mL of fluoride solution is added before acidifying the sample and there is no delay in titration, the method is also applicable in the presence of 100 200 mg/L ferric iron. 1.2 The Dissolved Oxygen (DO) Probe technique gives comparable results on all samples types. 1.3 The azide modification is not applicable under the following conditions: (a) samples containing sulfite, thiosulfate, polythionate, appreciable quantities of free chlorine or hypochlorite; (b) samples high in suspended solids; (c) samples containing organic substances which are readily oxidized in a highly alkaline solution, or which are oxidized by free iodine in an acid solution; (d) untreated domestic sewage; (e) biological flocs; and (f) where sample color interferes with endpoint detection. In instances where the azide modification is not applicable, the DO probe should be used. 2.0 Summary of Method 2.1 The sample is treated with manganous sulfate, potassium hydroxide, and potassium iodide (the latter two reagents combined in one solution) and finally sulfuric acid. The initial precipitate of manganous hydroxide, Mn(OH)2 , combines with the dissolved oxygen in the sample to form a brown precipitate, manganic hydroxide, MnO(OH)2 ,.
    [Show full text]