The density of solids - Journal of Chemical Education (ACS Publications)

Displacement and Flotation: An Introductory Experiment in Forensic Chemistry. Lisa A. Saccocio and Mary K. Carroll. Journal of Chemical Education ...
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Speclflc-Documented Assertion of the Term "Carbonlum" as Correct and the Term "Carbocatlon" as Incorrect To the Editor;

I t is the purpose of this letter to assert that the term "carbocation" has been incorrectly and inconsistently replacing the term "carbonium ion" in some quarters, by defining the basis for the use of thesuffix "-onium" as applying to species containing more bonds than usual, as well as a ~ o s i t i u echaree at the atom in ouestion . . . asammonium. oxonium, sulfonium, and phosphonium . . . so that consistency-with-definition demands a "carbonium" species to he the likes of the mass spectrometrically detected CH&+(pentavalent). Hence, accordina to this definition. the likes of the species CR3+,though posit&ely charged a t the atom in question, is stated to possess less bonds than its usual four . . . and therefore must he given a term other than "carhonium" . . .and is consequently dubbed "carbocation". The followiue enumerates a snecific-documented asnertion that the original term "carhonium" is actually correct, while the recently introduced term "carhocation" is incorrect in its definition, inconsistent in its application, and unnecessary to invoke as a new classification term. (1 I The species, CR1'. is universally asserted rn be ~ p and ' hence possesrrs its uruol rhree groups.. . not lese bonds. as stated in the a h o w definition. Therefwe, the ahwe definition is based on an incorrect premise. (2) The mass spectrometrically detected CHs+ cannot he sp3hypervalent, hut its orbital hybridization could represent another oxidation state of carbon .. . just as there is normally trivalent "nitrous" and normally pentavalent "nitric". (3) The same texts, that replace the term "carbonium ion" with the term "carbocation" are calling the hypovalent,+ NOz, "nitronium," instead of "nitrocation", and the hypovalent,+ CI,+ Br, etc., "haloniurn" instead of "halocation" or no term, whatsover) .. . in the familiar electrophilic aromatic substitution .. . in embarrassing inconsistency with their crusade to revise and upgrade the nomeudature. (4) H2S04,sulfuric acid, is ostensibly hexavalent sulfur, as is its dehydration product, S03,sulfurictrioxide.. .but only the latter,in fuming sulfuric acid, will sulfonate benzene . . . by virtue of the resonance polarization of a sulfur-to-oxygen bond, resulting in a hypovalency of sulfur. Using the "carbonium" terminology, this would be "sulfonium character"; hut using "carbocation" terminology, this would be "sulfocation" character. ..that enables the electroohilic aromatic sulfonation. The "earhoeation" adherents term thdorotonated sulfhvdrvl . . eroun " . to he a sulfonium. as do those texts using "carbonium" nomenclature . . . to the latters' inconsistency, except that sulfur trioxide is given no "named" cationic character of the sulfur.

Furthermore, the application of the term ''carbocation" has been based on incorrect premises, and the error compounded by inconsistency of leaving the noncarbon cations with their original "onium" nomenclature. M. Gerald Schwartz Salve Regina College Newpnt, RI 02840

m e Density of Solids To the Editor:

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Electrolysis Omlsslon To the Editoc

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In conclusion, the term, "carbocation" is a n unnecessary replacement for the term "carhonium", the latter serving sufficiently for all positively charged species, regardless of number of bonds to the atom in question.. . with the provision, however, that cations (or cationic character) of different oxidation states of the atoms in question would need to he distinguished by nomenclature . . . as "enium", "inium", and "onium", for example.

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The experiment described in this Journal [1984,61,242] by Dale Burgess augmented with the "Density of Liquids" and entitled "Density Determination" is assigned to those in general chemistry at my school. - An irregular shapedobject, a regular shaped object, and two liquids are given for the required determinations. The irregular shaped object is weighed and then immersed in a liquid whose density is less than than of the selected object and will not act as a solvent on the obiect. The volume of the chosen liquid is recorded before and after immersion. The density of the object is the weight divided by the volume difference. The regular shaped object (a sphere, a cylinder, a cube, or a block) is weighed then measured with either a centimeter ruler or a micrometer caliper. The volume of the sphere, the cylinder, the cube, or the box are calculated by V = 4ar3/3, V = *r2h, V = P, and V = lwh after the dimensions are measured, and these volumes are divided into the respective weights to obtain the density. Suitable-size, calibrated beakers are weighed when empty and a specified volume of the chosen liquids are poured into the beakers and weighed again. The weight difference in each case divided by the specified volume is the denisty for the selected liquids. After completion a signed written report from each student is required by a specific deadline. The written format for all assigned experiments is (1)Name of Experiment, (2) Purpose, (3) Apparatus (Materials), ( 4 ) Description, ( 5 ) Data, (6)Calculations, and (7) Results and Conclusions. William D. Hill Jr. North Carolina Central University

Journal of Chemical Education

In a recent note we described a simple, compact electrolysis assembly for overhead projector demonstrations using two pencils as electrodes. We mentioned that we had seen Henry Bent use pencils as electrodes, but we failed to acknowledge Walter Selig's article [J. Chem. Educ. 1984, 61, 801 that describes electrodes made from pencils. We regret this oversight. Kenneth E. Kolb and Doris K. Kolb Bradley University Peoria. IL 61625

NOTICE TO AUTHORS Submlsslon Papers intended for publication in the Journal of Chemical Education should be suhmitted to J. J. Laeowski. Editor. , Department of Chemistry, University of exi is, ~ u k i nTX 78712. Papers for the Secondary School Section should be suhmitted to Mickey Sarquis, Secondary School Editor, Journal of Chemical Education, University of MiamiMiddletown, Middletown, OH 45042. In addition, papers intended for one of the Journal feature columns should be sent directly to the column editor a t the address given in the column heading the last time it appeared. Manuscript The manuscriot suhmitted should not have been ouhlished elsewhere'nor should it he under consideration for another publication. Quadruplicate typewritten c o d e s (theoriiinal and t h r c ~ c o p i & )musr heaubmitted. ~ y p i n g uf both text and ret'erences should bedouble-spaced with 1 in. margins on standard 8'12 X I 1 typing paper. Mimeographed copy and poor-quality, dot-matrix printer copy are not acceptable; use a t least a near-letter-quality printer for word processor print-outs. The title of the article should be followed bv the name and business or institutional address of the author. Full first names are encouraged; however, the author should use initials if helshe normallv uses that form in other publications. If the paper has been presented at a meeting, a footnote giving name of the society, date, and occasion should be included but should not he numbered. Organization. Papers may be organized into sections with headings and subheadings; however, it is Journal policy not to number sections or to publish papers in outline format. Sections may he referred to in the text either by section headings or by "above" and "below". Eouations and Reactions. Eauations (includine those for chemical reactions) that will be Ieferred to in the text should be numbered sequentially in parentheses at the right-hand margin; alphabetical subdesignations such as (13a), (13b) should be avoided. Except a t the beeinnine of a sentence. references to numbered'equations siould-he abbreviated (e.g., eq 1, eqs 1-3). If structures for compounds are numbered, they should be designated with bold-faced Arabic numerals, not Roman numerals. Reaction schemes should be treated either as figures, if they are long or complexly branched, or as equations if they are relatively simple. They should not he referred to as "Schemes" nor numbered senarately from figures or equations. Correct treatment of figures and tables is given in the section on illustrations below. Acknowledgment. The Acknowledgment should he placed at the end of the text but before the Literature Cited. rather than in the form of a footnote. Journal style does not use professional, social, or academic titles under most circumBtances in either the text or the Acknowledgment. General Considerations. The usual editorial customs, as exemolified in the most recent issues of the Journal. should he foilowed as closely as possible. In general, the Journal follows the principles and practices suggested in The ACS Style Guide [Dodd, Janet S., Ed. American Chemical Soci-

ety: Washington, DC, 19861. The major deviations are treated in detail in this Notice. Since the Journal receives far more material than it can publish and since publication costs are very high, manuscripts should be limited to not more than 20 typewritten pages, including figures, tables, and literature citations. Manuscripts describing experiments should not exceed eight typewritten pages.

References and Footnotes In articles with six or more literature references, each reference should be designated by an italic or underlined numher enclosed in parentheses; this number should be on the same line as the rest of the text, (e.g., "This topic has been discussed by Smith (6)").References are to be assembled, arranged numerically in order of first appearance in the text, and placed at the end of the article under the heading Literature Cited. In the Literature Cited the numbers are followed by a period rather than parentheses, are not underlined, and are placed flush with the margin: " , if the ~-~ reference exceeds one iine, the succeeding line or lines should be indented. The list of references should he tvned. .. . doubled-spaced, using the bibliographic style outlined below. The Literature Cited section should contain only literature citations. The citation may contain short comments pertaining to the reference; any notes amplifying the text should be handled separately as footnotes, designated by a superscript, and numbered sequentially throughout the text. The footnotes should he collected, double-spaced, on a separate sheet at the end of the article, not interspersed throughout the text. In papers containingfive or fewer literature references it is usually desirable that the references he handled as footnotes. Such references should he designated by superscripts (e.g., "This topic has been discussed by Smith'") and numhered in sequence with any explanatory footnotes. The footnotes should be placed at the end of the text in numerical order. They should follow the same bibliographic style as shown below for Literature Cited. Explanatory notes, such as present address and corresponding author, should be designated beside the author's name by superscripts numbered in sequence with other footnotes in the article. When q ~ w i i i rliterature cirnrions are not made but \\hen it wemsdesiral~leto append agenernl hihlioyraphy, nrrange113.nuthors' last uamrs. mew sho~lldbe tnadci~ll~habetically Bibllographlc Style The Journal of Chemical Education has changed its standard bibliographic style to resemble more closely those in other American chemical journals. The new style began with the January 1986 issue. All manuscripts should now conform to the new style: Those t h a t do not will be returned f o r revision before being considered f o r publication. The basic elements of the new style, with extensive examples, are outlined below. Journals

Manuscripts that deviate significantly from J o u r n a l style will be returned to the author f o r emendation before they will be considered f o r publication.

I. Pfluger, R. W.; Lyster, M. A.; Lowe, J. A., 111. J . Org. Chem. 1982,

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47.1160-1 166.~ ~

2. Blake, P.; Henri-Rousseau, 0.;Merad, M. J. Chem. Educ. 1984, 61,957-961.

Note that all parts of the author's name except the last name Volume 64 Number 1 January 1987

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should he in the form of initials only. All authors' names should he eiven: do not use "et al." in the references ihowever, it is acceptable in the text). The name of the jourha~is underlined (includine J. Chem. Educ.): this is followed hv the year, volume (in Lrabic, not ~oman,'numerals),and firdt and last page numbers. Reference to journals that renumber their pages with each issue should contain the issue number in parentheses after the volume number. 3. Nassau, K. Sci Am. 1980,243 (4), 124.

Serial publications, such as Aduances i n . . ., and Annual Reviews, that appear in hard cover and are listed as serials in the Chemical Abstracts Seruice Source Index should be treated as journnls. Standard prxticeshould he followed inahhrevisring juurnal nnnies. Three abbreviations that authors should be particularly careful to observe are: '

Aust. =Austria(") Austral. = Australia(n) Educ. = Education

Books Reference to a whole book 4. Holmes, B. E.; Setzer, D. W. Physical Chemistry of Fast Reoc-

tions; Plenum: New York, 1980; Vol2, p 83. Reference to a whole hook of collected writings with a general editor 5 Benfry, O'P.. Ed. Classier irz the T h w q of Chrmtcol Cnmhnnl i v n ; Dover: New York. 1963.

Reference to a contribution in a book edited by other(s) 6. Pollard, R. T. fn Comprehensive Chemical Kinetics, 4th ed.; Bramford, C. H.; Tipper, C. F. H., Eds.; Elsevier: New York,

1977; Vol. 17, Chapter 2. The following abbreviations are used for the subsections of a book (Chapter and Part are spelled out): P PP Vol. (for a specificvolume) vol. (for number of volumes) Sect.

Names of publishing companies should be in the shortest recognizable form, for example, John Wiley & Sons, Inc. becomes simply Wiley. Place of publication should include only the name of the city if i t is a major, well-known one (e.g., use New York, not New York, NY). If thestate name is used it should he in the form of the standard postal abbreviation (e.g., Reading, MA). UnpublishedMaterials

Material accepted for publication but not yet published 9. Stankovich, M.; Fox, B. Biochim. Biophys. Acta, in press. Unpublished results 10. Wulff, W. D.; Chan, K. S.; Tang, P. C., unpublished results

Theses 11. Fisher, W. G. PhD Thesis, Cornell University, 1978.

lllustratlons and Tables

Not all articles lend themselves to illustration, but articles that do should be accompanied by as many pertinent illustrations as possible. The best possible selection of illustrations available will be made by the editorial staff. Include three cooies of the illustrations olus the original. As a rule. apparat"s, pa;ticularly if complicated, is best presented h i means of line drawings. P h o t o a r a ~ h sare sometimes sufficient, however. When-both caGbiobtained, it is generally desirable to include both with the manuscript. Illustrations must be in standard reproducible form. Photographs should be black-and-white glossies. Line drawings should be done in black ink with all lettering done by stencil or press-on methods. Typewritten designations are not heavy enough to reproduce satisfactorily, nor will those produced by the normal dot-matrix printer. The most common shortcoming of submitted illustrations is lettering that is too small in the original to be readable when the f&e is reduced tu column (re rnounlvd on srnndord 8'h X I 1 width. Firure, alr~~uld paper if they are not already that size; they should not exceed page size a s they cannot be reduced properly if they do. Tables should be placed on separate sheets a t the end of the paper, not interspersed through the text. All photographs, line drawings, a n d tables must b e provided with self-explanatory titles o r legends. The legends for the illustrations should be typed in numerical order, double-spaced, on a separate sheet. All figures and tables must be mentioned in the text. Each illustration should be marked in blue pencil on the margin with the name of the author, the figure number, and the title of the article to which it refers. Common Errors

Since the Journal will return manuscripts that do not conform to its style, the following list of the most common errors has been compiled to assist authors in checking their manuscripts before submission. The details of the correct format or style for each of these errors can be found in the preceding sections. Manuscript not double-spaced Manuscriot minted an both sides of the oaoer

The various categories of unpublished materials should he handled as shown in the examples below. Material submitted for publication but not yet accepted 7. Mitchell, N. J.;Hayes,S. C. submitted for publication inscience.

Personal communications (address and date optional) 8. Henderson, D. N.; Rankin, J. E., U. Northern South Dakota,

personal communication, 1962.

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Journal of Chemical Education

References cited out of order Explanatory footnotes included in the Literature Cited Literature Cited not double-spaced Figures and tables without captions Figures, captions, footnotes, and tables interspersed in text Figures with typewirtten lettering Figures with lettering too small to reproduce clearly