ASSESSMENT TASK 3
Chemical Monitoring and Management INTRODUCTION
This task incorporates the 3 assessment components.
Knowledge and understanding of: the practice of chemistry, applications and uses of chemistry and their implications for society and the environment, and current issues, research and development in chemistry bonding, energy, chemical reactions, carbon chemistry and stoichiometry
Skills in: planning and conducting first-hand investigations gathering and processing relevant information from secondary sources
Skills in: communicating information and understanding developing scientific thinking and problem-solving techniques
This task assesses knowledge and understanding and skills associated with Core 3: Chemical Monitoring and Management.
This task relates to the following outcomes:
H3, H4, H8, H9, H11, H14
This task will be marked out of 25.
You have 60 minutes to complete this task.
Part of this task involves analysis of stimulus material provided to students. The stimulus material should be brought to class on the date of the assessment task and used during the assessment task. The material may be annotated by the student in preparation for the task. No other notes, texts or other material may be used during the assessment task.
Atomic absorption spectroscopy (AAS)
Summarised from: http://en.wikipedia.org/wiki/Atomic_absorption_spectroscopy
Atomic absorption spectroscopy (AAS) is a spectroanalytical procedure for the quantitative determination of chemical elements, employing the absorption of optical radiation (light) by free atoms in the gaseous state.
In analytical chemistry the technique is used for determining the concentration of a particular element (the analyte) in a sample to be analysed. AAS can be used to determine over 70 different elements in solution or directly in solid samples employed in scientific research.
Atomic absorption spectroscopy was first used as an analytical technique, and the underlying principles were established in the second half of the 19th century by Robert Wilhelm Bunsen and Gustav Robert Kirchhoff, both professors at the University of Heidelberg, Germany.
The modern form of AAS was largely developed during the 1950s by a team of Australian chemists. They were led by Sir Alan Walsh at the CSIRO (Commonwealth Scientific and Industrial Research Organisation), Division of Chemical Physics, in Melbourne, Australia.
The chief difference between line source LS AAS and continuum source CS AAS
We have to distinguish between line source AAS (LS AAS) and continuum source AAS (CS AAS). In classical LS AAS, as it has been proposed by Alan Walsh, the high spectral resolution required for AAS measurements is provided by the radiation source itself that emits the spectrum of the analyte in the form of lines that are narrower than the absorption lines. The advantage of this technique is that only a medium-resolution monochromator is necessary for measuring AAS; it has the disadvantage that usually a separate lamp is required for each element that has to be determined. In CS AAS, in contrast, a single lamp, emitting a continuum spectrum over the entire spectral range of interest is used for all elements. Obviously, a high-resolution monochromator is required for this technique.
High Resolution Continuum Source Atomic Absorption Spectrometry (HR-CS AAS)
Summarised from: http://www.isas.de/Enhancements-in-HR-CS-AAS.555.0.html
The High Resolution Continuum Source Atomic Absorption Spectrometry (HR-CS AAS) has been developed in Berlin to overcome fundamental limitations of the well-established AAS technique. As a result, two novel instruments have already been introduced into the market.
High-resolution continuum source atomic absorption spectrometry (HR-CS AAS) is probably the most innovative technique in the field of atomic