What an Extended Essay is 

Put simply an Extended Essay is a 40 hour in-depth study of a focused topic in an IB subject¹ of your choosing written with a limit of 4000 words.

You do not have to be actually studying the subject as one of your six Diploma subjects but it obviously makes much more sense if you are. Usually students choose one of their three Higher Level subjects but this is not a requirement as some Standard Level subjects particularly lend themselves to Extended Essays. Chemistry probably does not fall into this category but nevertheless each year some Standard Level chemistry students do choose to do their Extended Essay in chemistry and some of these are very successful. The reason for choosing a subject that you study is that you will have a grounding in the language and methodology of the subject. You can only do your Extended Essay in chemistry if there is a teacher on the staff of your school who is competent in chemistry and willing to supervise it.

There is no hard and fast rule about the 40 hours. It is only a guideline. However if you spend much more time on this, you would probably be better advised to spend the extra time trying to improve your knowledge and understanding of one or more of your six Diploma subjects. You are more likely to gain a higher overall total Diploma score by doing this as your Extended Essay together with your marks for Theory of Knowledge can only gain you a maximum of three bonus points. There is a rigid rule about the 4000 words. If you exceed 4000 words you will be penalised when the EE is marked externally. External examiners are clearly instructed that they should not read beyond 4000 words or take into account anything written beyond the 4000 word maximum. This means that if you exceed the word limit you will compromise the assessment of your extended essay across all the criteria. 

An Extended Essay is a research essay. You will need to consult a variety of different sources and extract relevant material. Once you have settled on a sharply focused research question you will need to develop a reasoned argument (looking at the strengths and weaknesses of claims and counter claims) to reach a conclusion.

An Extended Essay must be all your own work. If you use material that is not your own (e.g. a quotation) you must acknowledge its source in a recognised way. Your supervisor is allowed to give you support and guidance but neither they, nor anybody else, must do the work for you. 

Your Extended Essay fulfils many of the aspects of the IB Learner Profile. Through the process of independent learning you gain knowledge and understanding. You will need to engage in extensive reflection during the research process, retain an open-mind and present your argument in a balanced and fair way. The whole process involves considerable intellectual risk-taking. 

(¹ It is also possible to do a World Studies Extended Essay involving chemistry as one of the two interdisciplinary subjects. This provides you with the opportunity to undertake an in-depth interdisciplinary study of an issue of contemporary global significance.  The best topics involve connections between specific or local places, people, phenomena or experiences and the larger global framework in which they take place. You should talk with your supervisor if you are interested in pursuing this option.)