qualitative analysis 1

Download Qualitative analysis 1

Post on 18-Jul-2015




1 download

Embed Size (px)


Qualitative Analytical Chemistry

Qualitative Analytical ChemistryDr Mark SelbyE-Block E413D (GP)m.selby@qut.edu.au

Increasing chemical literacyDeveloping skills and knowledge that are relevant to chemical industry and research.Achieving this:Practical skills through the laboratory programDeveloping chemical concepts (mental models) through simulations --- a work in progressAlignment of fundamental principles taught in lectures with practical work in the laboratory (where possible)ObjectivesLiteracy, in its most common usage, is defined as the ability to read and write. These are basic skills and the absence of one or both is considered to be a handicap in an industrialized society.

In pursuit of chemical literacy: A place for chemical reactionsDouglas Bond J. Chem. Educ., 1989, 66 (2), p 157

we start with the hypothesis that a chemically literate person is one who is curious about chemical phenomena and makes an effort toward satisfying that curiosity. If this person is a chemist or chemistry student, he or she will regard the need to satisfy this curiosity as more orless a full-time effort

There are some scientific values or attitudes that must be part of this curiosity that give some meaning to the search and that make it possible to deal with the uncertainties that will arise.Chemical LiteracySee information on pages 12 17 of the Practical Manual and the notes under the heading Review in these PowerPoint slides.Handwritten reports are acceptable and will not result in any reduction in grades.Over the course of the semester in this unit you should be developing your skills in writing reports that will meet a standard acceptable to industry or research.Improvement in writing reports is to be judged by the structuring of the report, the standard of written communication, quality of recorded observations and discussion of results, and the use of chemical equations.The mechanics of writing your report (i.e., handwritten versus word-processing) is of secondary importance (but word processing may be expected in Industry or research).

Writing chemical equationsTools for writing reportsThe nuts and bolts of word processing for chemistryThe RSC font:

The Royal Society of Chemistry font is a specialist chemistry font that may be downloaded free and used on PCs and Macs. This font allows chemical symbols to be introduced easily into Word documents.


Fonts for Chemistry

Chem97 Font:

ChemFont97 is a Windows font package that simplifies the entry of chemical equations and notation. The font includes all upper and lower case Greek characters, superscripts, subscripts, many chemistry-specific symbols like reaction arrows. ChemFont97 comes in two styles: serif, which is like Times New Roman, and sans-serif, which is like Arial.

6Office 365 University

Handy cloud storage . Always have your work with you.

Wolfram AlphaWolfram Alpha solves chemical equations and provides comprehensive chemical data.

Apps for Android and iPad.Handy for Mol. Wt.

Collaborate but dont plagiarise. Make sure you understand the difference!See for instance:http://www4.caes.hku.hk/writing_turbocharger/collaborating/default_answers.htmCollaborate but dont PlagiariseSingle atom anions are named with an -ide suffix: for example, F is fluoride.Compounds with a positive ion (cation), the name of the compound is simply the cation's name, followed by the anion. For example, CaF2 is calcium fluoride.Cations able to take on more than one positive charge are labeled with Roman numerals in parentheses. For example, Cu+ is copper(I), Cu2+ is copper(II). An older, out-dated notation is to append -ous or -ic to the root of the Latin name to name ions with a lesser or greater charge. Under this naming convention, Cu+ is cuprous and Cu2+ is cupric.

IUPAC nomenclature Things you should already knowBut probably need to revise!Oxyanions (polyatomic anions containing oxygen) are named with -ite or -ate, for a lesser or greater quantity of oxygen. For example, NO2 is nitrite, while NO3 is nitrate. If four oxyanions are possible, the prefixes hypo- and per- are used: hypochlorite is ClO, perchlorate is ClO4.The prefix bi- is an out-dated way of indicating the presence of a single hydrogen ion, as in "sodium bicarbonate" (NaHCO3). The preferred method specifically names the hydrogen atom. Thus, NaHCO3 would be called "sodium hydrogen carbonate".The prefix thio indicates the substitution of oxygen by sulfur, so that thiosulfate ion is a sulfate ion SO42- with one oxygen replaced by a sulfur as in S2O32-.The preferred IUPAC name for the protonated species H2S2O3 is thiosulfuric acid.IUPAC nomenclature Monatomic anions:

Cl chlorideS2 sulfide P3 phosphidePolyatomic ions:

NH4+ ammonium H3O+ hydronium NO3 nitrate NO2 nitrite ClO hypochlorite ClO2 chloriteClO3 chlorate ClO4 perchlorate SO32 sulfite SO42 sulfate HSO3 hydrogen sulfite HCO3 hydrogen carbonateCO32 carbonate PO43 phosphate HPO42 hydrogen phosphate H2PO4 dihydrogen phosphate CrO42 chromate Cr2O72 dichromate BO33 borate AsO43 arsenate C2O42 oxalate CN cyanide SCN thiocyanate MnO4 permanganateList of common ion namesHydrates are ionic compounds that have absorbed water. They are named as the ionic compound followed by a numerical prefix and -hydrate. The numerical prefixes used are listed below:

For example, CuSO4 5H2O is "copper(II) sulfate pentahydrate".

Naming hydratesmono-di-tri-tetra-penta-hexa-hepta-


Acids are named by the anion they form when dissolved in water. If an acid forms an anion ending in ide, then its name is formed by adding the prefix hydro to the anion's name and replacing the ide with ic. Finally the word acid is appended.For example, hydrochloric acid forms a chloride anion. With sulfur, however, the whole word is kept instead of the root: i.e.: hydrosulfuric acid. Secondly, anions with an -ate suffix are formed when acids with an -ic suffix are dissolved, e.g. chloric acid (HClO3) dissociates into chlorate anions to form salts such as sodium chlorate (NaClO3); anions with an -ite suffix are formed when acids with an -ous suffix are dissolved in water, e.g. chlorous acid (HClO2) disassociates into chlorite anions to form salts such as sodium chlorite (NaClO2).

Naming acidsThe four oxyacids of chlorine are called hypochlorous acid (HClO), chlorous acid (HClO2), chloric acid (HClO3) and perchloric acid (HClO4).Their respective conjugate bases are the hypochlorite (ClO-), chlorite (ClO2-), chlorate (ClO3-) and perchlorate (ClO4-) ions.The corresponding potassium salts are potassium hypochlorite (KClO), potassium chlorite (KClO2), potassium chlorate (KClO3) and potassium perchlorate (KClO4).

Oxyacids of chlorineAcidFormulaAnions

NotesSulfuric acidH2SO4sulfate ,SO42- and hydrogen sulfate, HSO4-Thiosulfuric acidH2S2O3thiosulfate, S2O32

Aqueous solutions decompose:{write equation}Sulfurous acidH2SO3Sulfite, SO32- and hydrogen sulfite, HSO3-Aqueous solutions decompose:{write equation}Oxyacids of sulfurOnly the most common oxyacids are shown in the table below: Hint: see Prac. Manual pages 25 and 26When the metal has more than one possible ionic charge or oxidation number the name becomes ambiguous. In these cases the oxidation number (the same as the charge) of the metal ion is represented by a Roman numeral in parentheses immediately following the metal ion name. For example in uranium(VI) fluoride the oxidation number of uranium is 6. Another example is the iron oxides. FeO is iron(II) oxide and Fe2O3 is iron(III) oxide.An older system used prefixes and suffixes to indicate the oxidation number, according to the following scheme (next page):

Traditional namingThis system has partially fallen out of use, but survives in the common names of many chemical compounds: e.g., "ferric chloride" (instead calling it "iron(III) chloride") and "potassium permanganate" (instead of "potassium manganate(VII)").Traditional namingOxidation stateCations and acidsAnionsLowesthypo--oushypo--ite-ous-ite-ic-ateper--icper- -ateHighesthyper--ichyper--ateWhen naming a complex ion, the ligands are named before the metal ion.Write the names of the ligands in alphabetical order (numerical prefixes do not affect the order.) Multiple occurring monodentate ligands receive a prefix according to the number of occurrences: di-, tri-, tetra-, penta-, or hexa. Polydentate ligands (e.g., ethylenediamine, oxalate) receive bis-, tris-, tetrakis-, etc.Anions end in ido. This replaces the final 'e' when the anion ends with'-ate', e.g. sulfate becomes sulfato. It replaces 'ide': cyanide becomes cyanido.Neutral ligands are given their usual name, with some exceptions: NH3 becomes ammine; H2O becomes aqua or aquo; CO becomes carbonyl; NO becomes nitrosyl.Naming complexesWrite the name of the central atom/ion. If the complex is an anion, the central atom's name will end in -ate, and its Latin name will be used if available (except for mercury).If the central atom's oxidation state needs to be specified, write it as a Roman numeral in parentheses.Name cation then anion as separate words.

Examples:[NiCl4]2 tetrachloridonickelate(II) ion [CuNH3Cl5]3 amminepentachloridocuprate(II) ion [Cd(en)2(CN)2] dicyanidobis(ethylenediamine)cadmium(II) [Co(NH3)5Cl]SO4 pentaamminechloridocobalt(III) sulfateNaming complexesSolubleInsolubleGroup I and NH4+ compoundsCarbonates (Except Group I, NH4+ and uranyl compounds)Nitrates, chlorates (all are highly soluble)Sulfites (Except Group I and NH4+ compounds)Acetates (Ethanoates) (Except Ag+ compounds)Phosphates (Except Group I and NH4+ compounds)Chlorides, bromides and iodides (Except Ag+, Pb2+, Cu+ and Hg22+)Hydroxides and oxides (Except Group I, NH4+, Ba2+, Sr2+ and Tl+)Sulfates (Except Ag+, Pb2+, Ba2+, Sr2+ and C


View more >