Extended Essays in Chemistry
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An extended essay (EE) in chemistry provides students with an opportunity to investigate a specific aspect of a material of our environment. The essay must be characterized by a particular chemical emphasis within a more general set of research criteria. Chemistry is the science that deals with the composition, characterization and transformation of substances. A chemistry EE should incorporate chemical principles and theory, and emphasize the study of matter and of the changes it undergoes. The outcome of the research should be a coherent and structured piece of writing that effectively addresses a particular research question and arrives at a particular, and preferably personal, conclusion or response to the research question. |
Examples:
| Broad Topics | Focused Topics |
| Study of sea water | Determination of chloride, nitrate and calcium ion concentration in sea water |
| Study of milk | Spectrophotometric determination of vitamin B2 content in cow’s milk |
| Theoretical investigation of hydrazine | Investigating the possibility of substituting hydrazine for kerosene as a rocket fuel |
| DNA in plants | Extracting DNA from peas using two different primary alcohols |
Research in Chemistry
An EE in chemistry may be based on:
Since chemistry is an experimental science, students are strongly encouraged to undertake experimental work as part of their research, although this is not compulsory.
In order to place their research into the appropriate context, students should research the area of the investigation before commencing any experimental work. Where possible, they should consult original research using:
Many of the best essays are written by students investigating relatively simple phenomena using apparatus and materials that can be found in most school laboratories, and this approach is to be encouraged.
Secondary Research
Students can also use data collected elsewhere. For example, for a research question that requires calculation of enthalpy changes in reactions, students can obtain average bond enthalpies from databases and manipulate these in order to answer the question.
However, to achieve high marks, students must devise their own method to analyse the secondary data in a way that leads to a specific answer to their research question.
Examples:
| Topic | The effect of storage temperature on alkaline battery discharge time |
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| Research question | What is the effect of storage temperature on the operational lifespan of an alkaline battery? |
| Approach | Experimental: set of 3 batteries is subjected to 5°C, 20°C, 30°C, 40°C, 50°C for a specific period of time, after which the batteries are discharged. Voltage is measured before and after storage period. |
| Topic | Investigation of changing reflux time on the yield of aspirin |
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| Research question | Does increasing reflux time increase the percent yield of aspirin for the reaction between acetic anhydride and salicylic acid? |
| Approach | Experimental: aspirin is produced from acetic anhydride and salicylic acid at varying reflux time intervals. |
| Topic | Replacement of coal with natural gas for electric power generation |
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| Research question | What would be the reduction in CO 2 emission (measured as % change by mass) in Germany of replacing all coal-fired power plants with modern CH 4 power stations? |
| Approach | Data based: calculate the CO 2 emission per kWh using public domain data for the heat of combustion, composition and efficiency of coal and natural gas power plants. |
| Topic | Periodic properties of super-heavy elements 113–118 |
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| Research question | Can the physical and chemical properties of the undiscovered elements be predicted using the law of periodicity? |
| Approach | Literature based: examine the ionization potential, electron affinity and other periodic trends, predict if the super-heavy elements obey the periodic law. |
Chemistry Sources
Even students doing primary research will still need to reference secondary sources. And students relying entirely on secondary sources will need to find sources not only of written information but also experimental data which they can analyze.
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In Context Databases Gale In-Context databases offer topic pages and the Topic Finder search feature. This video will show you how to use topic pages.
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Gale OneFile Databases Gale OneFile databases have two features to help you find search words as well as topics and sub-topics. Use the "subject guide search" feature in Gale OneFile databases to help you find good search terms.(tutorial video). Use the "topic finder" to help you find good topics and sub-topics (tutorial video)
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Environmental Studies and Policy
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National Science Digital Library The NSDL is an open access library of digital content relevant to all aspects of hard and applied sciences. |
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Writing the Essay
An essay in the sciences requires is more than just generating and presenting data. Analysis of the data is also essential. The main body of the essay should consist of an argument or evaluation based on the data or information presented. You can gather your own data through a variety of methods, or rely on secondary data. You should use graphs, tables, or diagrams to point out the significance of your findings.
You should ensure that the main body of the essay is well structured and has an obvious logical progression. You can use numbered and headed paragraphs to impose a clear structure. Your evaluation should show that you understand the the data they have collected and its significance to the world.
In your analysis, you should also describe and explain the limitations imposed on the research by factors such as
Students should also consider biological limitations such as:
Safety and Ethics in Choosing a Topic
In all cases where human subjects are used as the basis for an investigation, clear evidence of informed consent must be provided in accordance with the IB guidelines.
Some topics may be inadmissible because their means of investigation are unethical. For example, investigations that:
Some topics may be unsuitable because of safety issues. Adequate safety apparatus and qualified supervision is required for experiments involving dangerous substances such as:
Other topics may be unsuitable because the outcome is already well known and documented in standard textbooks.
