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A versatile, simple instrument, the isothermal heat conduction calorimeter, for studying processes in biology, physics, and chemistry is discussed with presentation of five related experiments for students involving heat capacity of solids, acid-base titration, enthalpy of vaporization of solvents, cement hydration and insect metabolism. It is surprising that these calorimeters are not commonly used in teaching as in industry monitoring calorimetry based on the heat-flow calorimeter principle is being rapidly developed, and the applications can be made into interesting student experiments.

The status of procedural knowledge of sophomore science and chemical engineering students at the University of Cape Town has been investigated. Little difference was seen in the two groups. A model of progression of student ideas about experimental data was developed using extensive data from high school students. The status of procedural understanding was investigated in freshman physics students to extend the model. One seventh of the students thought the purpose of replicating measurements was identification of a recurring value. This was disappointing. More than 40% of students replicate measurements to take a mean, but seem to see the relationship of spread to mean only when the means are the same. A third of them intend to calculate the spread. More than 50% try to draw a best fit for a straight line graph. Findings will affect design of the the new practical manual. The design and sequencing of experiments of a new sophomore course will be affected. Mode of presentation of titration exercises is to be reviewed.

Capacities of major types of scientific calculators are compared. Calculators of four types were applied to solving a quadratic equation and a graphic calculator was applied to various chemical problems, equilibrium ones, and graphic display of a concentration-vs-time and acid-base titration curves. The graphic scientific calculators with their built-in mathematical program packages were found to be very effective. It can be helpful for a teaching institution to have a calculator policy and for it to adopt a certain scientific calculator for use by its students. Balancing a reaction with matrix algebra has been covered previously .

A general computer simulator can be used to teach chemistry students about acid-base titrations. An similar algorithm might be used for expert systems. General equations based on well, known principles, for instance the Guldberg-Waage law of chemical equilibrium and conservation of mass and charge, can be used to calculate titration progress curves. The titration curve is essentially inverted to make it amenable to closed-form mathematical description.

The outcome of a project at the University of Melbourne in 1992 on imparting the knowledge of quantitative volumetric analysis skills to first year chemistry students showed that the laboratory skills of a group can grow significantly with computer-assisted learning. The feedback data from the tutorial and from video observation during the first laboratory session has indicated a good improvement in the learning and application of skills.

A chemistry software package, EQUIL has been developed that can produce almost any titration data a person can imagine. The advantage of the EQUIL software is that a person can turn on or off activity coefficients, and enter competing equilibria that can affect pH and buffer dilutions. It should be noted that in the place of the real titration experiments this program is a valuable source of easily simulated titration data.

Computer spreadsheets can be used in school laboratories to plot pH titration curves and have the advantage of allowing students to make instant investigations on the effect that parameter changes would have on the pH curve. An examination of the use of a spreadsheet for illustrating the effect of a strong acid titrated with a strong alkili, a strong acid titrated with a weak alkali and a weak acid titrated with a strong alkili, is presented.

Wingz, a Macintosh spreadsheet program by Informix Software, has a scripting feature which makes advanced titration plots easier and more accurate. This allows students to deal easily with a high degree polynomial. The scripting feature builds the plot with each calculation, and Wingz can generate three dimensional plots.

Studies on the determination of S(IV) and the formation of adducts relative to coulometric titrations in wine samples are presented for use in an instrumental analysis course for chemistry or pharmacy studies. Sulfites in white wines are measured. Kinetics of the reaction of iodine with S(IV) in the sample as an additive and on the release of S(IV) from the adduct are discussed.

An electroanalytical method for the microscale determination of vitamin C, ascorbic acid, has been developed for students in an instrumental analysis course at the Chemistry Inst. of the University of Brasilia. It combines simplicity and low cost with high precision and accuracy, yet is useful in colored sample solutions. Weight titration of the acid is carried out using (diacetoxyiodo)benzene (IBDA) as titrant in semi-aqueous medium and differential electrolytic potentiometry for the end-point location.

An undergraduate experiment in redox titrimetry involving determination of free lime in clinker and cement using iodometry can teach students several skills, extraction, filtration, redox and acid-base titrations, and statistical data analysis.Free lime is first extracted with nonaqueous ethylene glycol, the suspension filtered and allowed to react with a known excess of hydrochloric acid and the excess acid determined by iodometry. In speed, sensitivity and precision, the method is better than the classical British Standard (BS) method, which is discussed. It shows students how traditional wet chemistry can be used in industry and lets students learn about cement processing.

Students in sophomore-level quantitative analysis can learn by carrying out a practical experiment in titrimetry and atomic absorption spectroscopy that tests reduction of calcium concentrations by the Brita(R) water filtration system. The experiment is based on a classical Ca(super.2+) -EDTA complexometric titration. Students learning titration technique are more interested in experiments that pertain to something of significance to them,

A circular dichroism spectrophotometry experiment has been developed for chemistry students learning about acid-base titration of (S)-aspartic acid. The ionization constant of the protonated amino group is determined. To find the end points of an acid-base titration an unusual method is made possible because the analyte is a chiral molecule. The experiments can be used in analytical, physical or organic chemistry an in biochemistry lab courses at the intermediate or advanced level when students have background to integrate information from the different processes and where a CD spectrophotometer is available. An empty fume cupboard with a metal or ceramic tray is needed to prepare the stock solutions containing sodium perchlorate.

An approach to teaching conductimetric titrations of soluble acid-base systems using a predict-observe-explain activity is presented. The activity provides a contrast between weak and strong acids. It intgrates real-time computer-based gathering of data while improving the learning experience through scientific predictions.

Information about redox titration, which is an important technique taught in most general chemistry laboratory courses, is presented. Redox titration requires students to learn about titrating, oxidizing, and reducing agents. The details of an experiment in which percentage of iodine in povidone iodine is determined by titration with sodium thiosulfate are also presented.

Collaborative learning activities were suggested in order to teach science and for this a teaching activity was modeled based on collaborative identification scheme called as The Great Wakonse Earthquake. The earthquake was a fictitious scenario introduced as the motive for the participants to study suspect drinking water and introduce them to the concept of titration in chemistry.

A good understanding of dimensional analysis is a needed prerequisite to adequately perform and report quantitative chemical analyses in support of chemical processes. Some common teaching and learning misconceptions related to the volumetric dilution equation are discussed.

Students of geochemistry can learn by carrying out the determination of the surface chemical properties of a solid. Students can gain a basic understanding of geochemical modeling and some knowledge of a nalytical techniques including acid-base titrations, and UV or flame atomic absorption spectroscopy (FAAS) spectrophotometry. Students can use Microsoft Excel for calculations and for presentation of results.

A procedure for a m icroscale quantitative analysis of hard water samples using an indirect potassium permanganate redox titration has been developed for students of chemistry . The article focus is on analysis of the quality of data obtained using microscale techniques. It includes a comparison of student lab data in which accuracy and precision of microscale and mac roscale data are compa red. Loss of calcium oxalate precipitate during filtration is potentially a source of determinate error.

Experimental design for the undergraduate chemistry curriculm is discussed relative to multiplexed modeling using titrimetry and Microsoft Excel spreadsheets. A counterfeit coin activity with one counterfeit lead coin and 25 silver coins and a pan balance is presented. An experiment in which vinegar acidity is determined using titration is presented. It is simple and amenable to multiplexing in the design. In industry experiment design and optimization are important for economic reasons, but students will find their interest piqued by the prospect of finding ways to do less work.

Use of an automatic pipet and only 1-5 mL of analyte and a similar amount of titrant for microscale pH titrations is discussed. The fundamental equivalence concept is learned as it would be with macroscale titrations, but students would still need to do exercises to learn about macroscale glassware. Acid-base indicators can be used if an accuracy of 5-10% is acceptable, but accuracies approaching 1% can be achieved when computer analysis is used. Students learn about the automatic pipet and small volumes make replicate analyses not too costly. Students can see the impact of the technique on the precision of analysis quickly. The technique can be used at any level.

Chemical speciation can be used as a guide to understanding chemical titrations. Speciation modeling can be a quick, easy method of monitoring changes in experimental conditions. Chemical speciation is the oxidation state, concentration and composition of each of the species present in a chemical mixture. Titrimetric analysis often is used without gaining understanding of the underlying chemical principles, and if something goes wrong people usually cannot correct mistakes. Determination of magnesium and total magnesium and calcium in a mixture using ethylenediaminetetraacetic acid (EDTA) with the indicator Eriochrome black T (EBT) is the example discussed.

Students in undergraduate analytical chemistry courses can learn from carrying out an indirect potentiometric titration of Fe(III) with Ce(IV) using Gran's method. Some problems with other Gran's method experiments are avoided in this one. Ideal Gran plots can be obtained in almost all of the titration curve before the equivalence point.

Use of ascorbic acid, or vitamin C, as a standard for iodometric titrations is discussed. The substance is excellent, fast, accurate and easy-to-use for the standardization of iodine solutions. Students can analyze vitamin pills for the amount of ascorbic acid and standardize a solution in one lab period accurately and precisely.

Six automatic titrators have been integrated into experiments in three courses at the University of Florida in the analytical and physical chemistry laboratories. They are used in almost every week school is in session, mostly in introductory analytical chemistry laboratory. About 350 students in various scientific disciplines go through the course in a year. They get experience with automated analyses after they master fundamental techniques. Because small volumes can be accurately delivered, consumption of reagents has gone down, as has waste.

Expanded dimensional analysis and dating analogies are useful to analyze the results of concentrating or diluting unknown solutions before titrating them. The normality of an unknown 10 L NaOH solution is determined in three steps before titration with 1 L of 0.1 N HCl solution. The process of these three steps are described and chemistry students are taught that the concentration does not matter whether diluted or concentrated through imagining male and female dorms where the number of men and the number of women is equal regardless of how many rooms are in each dorm.