Octahedral to Square Planar Transition in Nickel Chelates
As this experiment is part of a subject on inorganic chemistry focussing of the fundamentals of aqueous transition metal chemistry, its aim is primarily to investigate the transformation between octahedral and square planar geometries in nickel chelates and help develop an understanding of the application of crystal field theory to the transformation. Students have already undertaken a course in physical chemistry and have covered the introductory theory in equilibrium thermodynamics. The experiment in its current form applies this knowledge and relates it to the relative stability of the complexes in equilibrium, thus reinforcing previously gained knowledge
Volumetric analysis: Accuracy and precision of a pipette
This experiment is designed to introduce students to volumetric analysis, and in particular to develop the student’s skill of accurate pipetting. Many of the students in the unit have had no previous chemistry background, and therefore do not know how to use a pipette. The experiment is followed up with an experiment in the following week that moves onto using volumetric glassware (including volumetric flasks and burettes) to perform a titration. The experiment also enables the students to recognise the difference between accuracy and precision and undertake a titration based calculation (in preparation for the experimental based activities the following week).
Chemical Reactions: Observing chemical changes
This experiment is designed for students who may have no chemistry background at all, as their very first general chemistry laboratory experience (Semester 1). Previously we had commenced the laboratory program with emission spectroscopy based experiments which was quite theoretical and some students found the experience quite overwhelming. The purpose of this experiment was to ease the students into the laboratory program by introducing them to the concept that chemicals can undergo changes which we can observe in various different ways. We can represent the chemical changes that are occurring by writing a chemical reaction in the form reactants à products.
Ion Exchange Chromatography
Ion exchange chromatography is a critical analytical technique routinely used for the separation of compounds based on their charge for a wide range of purposes. This experiment provides students with experience executing the technique, and also builds knowledge of the theory behind how the process works by using ion exchange columns to identify products of hydrolysed copper complexes. In so doing students are also exposed to and gain an understanding of the relationships between the strength of reaction conditions and products produced as a consequence.
This is a new experiment which is designed to engage students in their chemical studies and to enable them to investigate a topic of general and scientific interest. It is submitted to test whether it reaches the goal of being engaging for a first year science student who does not necessarily view themselves as a likely chemistry major.
Properties of Gases
This experiment allows students to experience the behaviour of gases. In particular, students discover for themselves via the experiment the basis for the ideal gas law, i.e. that all gases have the same kinetic energy at a given temperature. Students also observe the effect of temperature on gas pressure and discover the effect of aqueous solubility of CO2 on pH, i.e. the basis for the increasing acidity of the seas due to the build-up of CO2 emissions in the atmosphere.
Preparation of biodiesel from waste vegetable oil
This experiment synthesises biodiesel fuel by the transesterification of used vegetable oil via an acid catalysed reaction. The product biodiesel is characterized by simple viscosity and flammability tests. This experiment was first used at Cornell College, Iowa, and reported in Journal of Chemical Education in early 2011. Reactions of acid derivatives, such as esters are a standard part of university chemistry curricula. This transesterification reaction is an example of “green chemistry” which both reduces waste (used vegetable oil) and produces a useful produce (fuel) from a renewable feedstock.
Ester Hydrolysis and Acid Identification
In this experiment students are required to identify an unknown ester by hydrolysing it to the corresponding acid, which is in turn identified by its melting point. The experiment involves a number of basic synthetic organic chemistry techniques, including performing a reaction (ester hydrolysis) under reflux, reaction work-up and product purification (recrystallisation), and identification of an unknown compound.
Preparation, Distillation and Spectroscopic Identification of 2-Chloro-2-methylpropane
The experiment aims to introduce the use of synthetic glassware to the students. In particular, they are required to perform distillations – a procedure that they have only dealt with theoretically in lectures. The experiment also reinforces concurrent lecture material which introduces the idea of functional group transformations by providing an example of this synthetic tool. As such it both develops new practical skills and supports theoretical learning.
Synthesis of 6-Methylazulene
Synthesis of 6-methylazulene and exploration of its chemistry. A third year organic chemistry prac in the domain of synthesis and electrophilic aromatic substitution.
Anion incorporation into layered solids
This experiment was developed from industry-focussed research conducted at the home institution. It provides an introduction to layered solids and the phenomenon of intercalation with coupled interpretation of analytical data. It also utilises materials (gibbsite) produced in a regionally significant industry.
Determination of vanillin in imitation vanilla essence
In this experiment students will determine the concentration of vanillin in imitation vanilla flavouring. In this experiment students apply key principles of analytical chemistry to the analysis of a common food additive (vanillin). This includes calibration curves, extractions, Beer’s law and spectrophotometry.
Thermodynamics of the NO2 – N2O4 Equilibrium by FTIR
This experiment investigates the thermodynamics of a simple equilibrium process, namely the dimerisation of NO2 to N2O4 and is directly integrated with the lectures where the NO2 / N2O4 equilibrium is used as an example for the determination of thermodynamic parameters. It does so by measuring a portion of the infra-red spectrum as a function of temperature. The portion of the spectrum analysed allows the calculation of absorbance and hence concentration of the two species present in the mixture. This in turn enables calculation of the equilibrium constant K as a function of temperature. The temperature dependence of K allows determination of the enthalpy change for the process via the Van’t Hoff isochor equation. Using this value and the standard Gibb’s free energy change for the reaction at 25 °C (determined from interpolation of the results for K), the standard entropy may be estimated.
The most important concepts that the students will learn in this practical relate to the thermodynamical properties that allow us to predict the direction of spontaneous chemical change. These concepts range from simple Le Chatelier’s Principle, to more challenging concepts of chemical entropy. Students will learn, by experiment and experience, that temperature changes are often associated with chemical change, but that spontaneous changes can be accompanied by either an increase or decrease in temperature (exothermic or endothermic processes).
Reactions in Non-Ideal Solution – The Effect of Ionic Strength on the Rate of Reactions Between Ions in Aqueous Solution (the Kinetic Salt Effect)
In this experiment the Kinetic Salt Effect (the impact that increasing ionic strength has on the rate of a reaction in ionic solution) is explored. Students compare their findings to theoretical predictions. While being a simple experiment it offers several points of consideration for the student, making it an effective learning tool.
Laser-Based Liquid Prism Sucrosemeter
In this experiment students construct their own sucrosemeter using a He-Ne laser and hollow equilateral prism. Sugar solutions are placed in the prism and the diffraction of a laser beam through these solutions can be monitored as a function of concentration, enabling determination of ‘real’ unknown solutions (cordial, soft drinks etc.). If available, a commercial refractometer is an ideal addition to the experiment as students can compare the results of their constructed sucrosemeter to the commercial one.
Redox Reactions Including Galvanic Cells
The experiment aims to link theoretical knowledge of electrochemistry presented in lectures with actual physical examples. Spontaneous redox reactions are observed in test tubes and students are asked to write chemical equations to explain their observations and then draw conclusions about what has occurred at a molecular level. Galvanic cells are constructed and the theoretical knowledge of half-cells, EMF, the Nernst equation, and solubility are related with actual measurements collected in a practical situation.
Determination of the Universal Gas Constant
This is a first year general chemistry experiment, which is conducted by students pursuing their studies in sciences, pharmacy, engineering etc. It gives the students an understanding of methods of collection of gases, consolidates on theoretical aspects of kinetic theory of gases dealt in lectures and helps them to recognise the different units in which the properties of matter can be expressed and also emphasises on their mathematical skills to interconvert units.