INTRODUCTION TO ANACHEM

• Modern techniques such as atomic absorption spectroscopy and ICP-MS (Inductively coupled plasma mass spectrometry) are able to quickly detect the presence and concentrations of elements using a very small amount of sample.
• Course Units: 5 units (3 units lecture, 2 units laboratory)
• In Quantitative chemistry, determination of the proportion of components in a substance is a type of analysis.
• Divisions of Gravimetric Analysis include Analysis involving the accurate measurement of weight of substance being determined which may be isolated in pure form or converted to another substance of known composition by making it react quantitatively with another substance usually a precipant.
• All zeroes which are simultaneously to the right of the decimal point and at the end of the number are always significant.
• Chemical, Physical, and Biological are divisions of analysis based on the materials used.
• Zeroes in between the decimal point and the first (if <1) or last (if >1) non-zero digits are not significant.
• Volumetric Analysis, Gravimetric Analysis, and Special Methods are divisions of quantitative analysis.
• Divisions of Volumetric Analysis include Neutralization, Precipitation, Compleximetry, and Oxidation-reduction.
• Qualitative Analysis is a method of analytical chemistry which seeks to find elemental composition of inorganic compounds and the functional group of organic compounds.
• Ultramicroanalysis, Microanalysis, Semi-microanalysis, and Macroanalysis are divisions of analysis based on sample size.
• Analysis can be based on sample size, the extent of determination, the nature of methods, and the materials used.
• Classical method, Instrumental method, and Miscellaneous or special method are divisions of analysis based on the nature of methods.
• In Qualitative Chemistry, Identification, Composition determination, and Ascertainment of impurities are types of analysis.
• Proximate analysis and Ultimate analysis are types of analysis based on the extent of determination.
• Quantitative Analysis in analytical chemistry, the measurements of quantities of substances produced in reactions rather than simply noting the nature of the reactions.
• Special Methods are types of analysis which require a distinct type of technique such as analysis of crude drugs, assay of fats and fixed oils, assay of volatile oils and assay of alkaloids.
• Analytical Chemistry: Branch of science that deals with the separation, identification and determination of the components in a sample.
• Analytical chemistry is particularly concerned with the questions of "what chemicals are present, what are their characteristics and in what quantities are they present?"
• 1st analytical group of cation

  Ammonia is used as a reagent to distinguish between the other two.
• PbCl 2 is soluble in hot water, and can therefore be differentiated easily.
• 1st analytical group of cation

  
  

  AgCl dissolves in ammonia due to the formation of the complex ion [Ag(NH 3 ) 2 ] + , while Hg 2 Cl 2 gives a black precipitate consisting of a mixture of chloro-mercuric amide and elemental mercury.
• The second analytical group of cations consists of ions that form acid-insoluble sulfides, including: Cadmium, Bismuth, Copper, Arsenic, Antimony, mercury
• 1st analytical group

  A filtrate obtained after first group analysis of Pb 2+ contains an appreciable concentration of this cation, enough to give the test of the second group, viz. formation of an insoluble sulfide.
• 1st analytical

  AgCl is reduced to silver under light, which gives samples a violet colour.
• Specialized Analytical Methods and Equipment include Distillation, Microscopy, Polarimeter, Refractometer, Dessicator, Oven, Moisture Balance, Chromatography, Spectroscopy, Polarography, and Biological tests.
• The most important cations in the first group are Ag + , Hg 2 2+ , and Pb 2+ , whose chlorides cannot be distinguished from each other by their colour and are all white solid compounds.
• Pb 2+ is usually also included in the 2nd analytical group.
• PbCl 2 is far more soluble than the chlorides of the other two ions, especially in hot water.
• The first analytical group of cations consists of ions that form insoluble chlorides, usually separated using hydrochloric acid at a concentration of 1 to 2 M.
• 1st analytical of cations

  Higher concentrations of Cl - cannot be used for the aforementioned reasons.
• Physico-Chemical Methods are analysis based on some specific physical or chemical property or properties of the substance being analyzed with the use of instruments such as: spectrophotometer, chromatograph units, polarographer, polarimeter, flourometer.
• 2nd analytical group

  
  

  The sulfides of As 3+ , As 5+ , Sb 3+ , Sb 5+ , Sn 2+ , Sn 4+ are soluble in yellow ammonium sulfide, where they form polysulfide complexes.
• Nitrates can be reduced to ammonia.
• The 2nd analytical group of cations includes reagents that give sulfide in solutions, such as Hydrogen sulfide and CH3CSNH 2 (Thioacetamide/ATK).
• Acids beside HCl are rarely used in the test with the sulfide ion.
• The 412nd analytical group of cations includes cations whose precipitates are almost indistinguishable, except for CdS which is yellow.
• After separation, the easiest way to distinguish these ions is by testing flame colour: barium gives a yellow-green flame, calcium orange-red and strontium deep red.
• Cations which are left after carefully separating previous groups are considered to be in the 5th analytical group.
• All the precipitates, except for HgS, are soluble in dilute mineral acids.