GCSE: Chemistry Essays, Coursework and Assignments

"#1# In this essay, the student presents the write-up of an experiment into rates of reaction in a clear, logical order. A good level of understanding is demonstrated, with key terms being explained such as what the independant and dependant variables are. The candidate begins with a solid hypothesis to investigate and ends with a conclusion to analysise the results, in which there are comments on whether the original idea was correct or not. This is important as, even if your hypothesis was wrong, it indicates you can, not only, correctly carry out an experiment but also identify what the results show. #2# As already mentioned, this student set out with a clear aim for the task. They carried out the investigation to the level of detail expected at GCSE level, with a written explanation of the method and all the background formulae. The conclusion is logical based on the evidence and the student does a good job of summing up the results of the experiment, however, and improvement would be to also add some information on why these results occurred as opposed to linking to a website with an explanation. In general though, the candidate displayed strong understanding as well as additional skills such as drawing the diagrams and graphs which is very important for scientific subjects. There is a good discussion on errors that could have been made, although this could have been expanded on a little. It is important to understand errors in experiments as they can have a huge bearing on the results and a more insightful analysis of this could have really made the essay stand out. #3# The investigation is easy to follow because of the precise use of language and the fact that there are little-to-no grammatical or spelling errors; technical terms are also used when necessary. A good feature is the use of subtitles for each paragraph as they make the logical progression of the task clear to see. It makes life of the examiner a lot easier too, as it immediately shows that the student knows what the subject well and has hit all the assessment objectives. One criticism that could be made is that, perhaps, the student has stuck to the structure too rigidly and shows a lack of creativity, but at GCSE level, this is unlikely to be marked down at all, especially in a scientific subject."

"#1#There is not so much a posed question for this piece as more an instruction to discuss and inform about the nature of the atom, which the candidate does very well. The piece includes a good look at the history of the atom and its fundamentals which is essential to understanding the atom and, by extension, chemistry. One thing that could be done better is to give examples of chemical properties, such as reactivity to illustrate the nature of the periodic table to have atoms with similar chemical properties situated together. An example of this could be the high activity of the group 1 alkali metals. The explanation of isotopes is good, however the section about sub-atomic particles should come before this to allow the candidate to elaborate more about protons. #2#Most points have been made in the above section due to this being a piece that does not require a large amount of analysis. One thing that I would say however is that there should be a conclusion for a piece such as this – the candidate could talk about how this knowledge of the atom is applied in modern chemistry, however the topic is broad enough that a look specifically at just the atom in itself still works well. #3#The candidate’s quality of writing is extremely good – sentences and paragraphs are constructed well allowing effective conveyance of meaning. Terms are defined precisely and succinctly lending a lean flow to the piece. One thing though, the paragraph on sub-atomic particles is repeated at the end of the piece – it does not elaborate on anything and so should be deleted. Overall the piece is very good – an accurate informative description of the atom is given, with a look at different properties and aspects of the atom."

"#1# The author has carried out two different experiments in order to work out the formula for Hydrated Iron (II) sulphate. They have then compared the two methods and come to a conclusion as to which was the best, as well as calculating a correct formula (FeSO4:7H20) in one of the experiments – the one they decided was the best. They have shown a clear method and have carried out their experiment well (their data has no obvious anomalies, and they have worked out a correct formula). They also repeated the experiment to increase the reliability of their results, and considered the spread of the data when comparing the two methods. #2# The author has used their results to work out the correct formula for Hydrated Iron (II) Sulphate, and have shown their workings clearly. They have mentioned potential causes of uncertainty, such as the precision of measuring instruments, and used this to suggest improvements to their experiment, although they occasionally conflate the terms ‘error’ and ‘uncertainty’. Sources of uncertainty are not in themselves errors, but are opportunities for errors to occur. I would have mentioned the greater number of sources of uncertainty in the second experiment due to the larger number of measurements when comparing the experiments, and then compared the percentage uncertainties in each experiment. It may not have been necessary at GCSE to calculate the values of all the uncertainties, but I would have calculated the easier ones such as the precision of measuring equipment (half the smallest measurement possible) in order to gain more marks and be able to compare the experiments more. #3# The author’s spelling and grammar is very good throughout. The report is very well laid out, with clear headings and sections. However, I would have included sections on ‘reducing uncertainties’ and ‘safety precautions’, rather than briefly discussing them in the conclusion. A report should usually allow the reader to easily carry out the experiment themselves, so this information should be easy to find in the report as it is very important. It may also have been useful to include a labelled diagram of the setup of the equipment for the same reason. Overall, the report is very well written and shows a good understanding of the chemistry involved and an ability to perform complicated calculations based upon real data. "

"#1#Overall an exemplary piece of work for this level of qualification. Sets out in the introduction some of the science behind the rates of reaction and states what he is trying to measure. In the main body of text goes into the science behind rates of reaction to a very concise and clear extent, and explains the science very well. Later on goes into the aim of the experiment which actually differs slightly from the intentions displayed in the introduction, so the aim should be rewritten to reflect the overall intentions of the experiment as they are only investigating the concentration of the liquid which is stated as the dependent variable, not what in general affects the rate of an experiment. Conclusion adequate and very detailed. #2#The level of analysis is very detailed and consulted from a wide range of sources for this level. Able to set out the experiment well, and provides a well thought out and accurate evaluation and conclusion for this experiment that reflects a student at the top level of GCSE grades. #3#Punctuation, grammar and spelling all fine. Writer communicates meanings very clearly and all of the chemistry is correct."

"#1# An excellent coursework that produces a very detailed series of tests for identification of organic compounds. This is an A Level coursework however it is classified under GCSE. This coursework might be extremely confusing for the GCSE level chemistry. The coursework is very clear and easy and well-organised to give the reader a very complete information about this procedure. The usage of diagram/chart to show the series of the reactions is incredible however for this level of coursework, diagrams for the apparatus used for each test should be included. #2# The analysis of the experiment is good and produces a very detailed manual for the reader. However there can be some debate concerning some stages of the test. The usage of Universal indicator might not be accurate as the pH of phenol is above 5 and very close to 6 which is not easily detected by Universal indicator so usage of a digital pH meter or blue litmus paper would be a better option. I can also point out at the test used to distinguish between an alcohol and an ester. This test definitely works unless a tertiary alcohol is used as stated however we do not know if the alcohol is tertiary or not. so it is better to use Phosphorus pentachloride (PCl5) to detect alcohols as all alcohols produced steamy fumes of Hydrogen Chloride with PCl5. In another part of the coursework, If Brady's reagent test is negative it would only conclude that alcohol or ester is the compound since the posiblity of Phenol & Carboxylic acid is already eliminated before doing the test with the Brady's reagent. However in general this is a very excellent coursework. #3#The grammar, spelling and the usage of technical terms are completely fine and there is nothing to be pointed out."