by Splash
NB: Since writing these reports are a component of school internal assessment, this guide may not be 100% compatible with other schools- if your teacher has differing advice, then make sure you follow his/her advice and avoid mine like a chemist would avoid having a bubble bath with sodium metal 
. Also example sections are quoted verbatim from what I wrote in the actual SAC-to give an indication of what may be required in SAC conditions (again, very dependent on school)- and I have not had this checked/edited externally. This is just a guide on what worked for me 
While writing practical reports for VCE Chemistry are not directly a requirement in the end of year exam- although the final question often assesses critical analytical skills of a report or experiment- they make up an important contribution to one’s overall VCE Chemistry SAC marks, which in turn contribute 40% to one’s overall study score. Now from experience, the skills in writing these reports and performing well in tests/exams are actually quite different, and performing well in one is not always conducive to performing well in the other.
So what makes practical reports so different? Well although both types of SACs seek to critique our overall understanding of the underlying chemical concepts, tests/exams tend to focus more on short answer questions, often simply with numerical answers, or concisely written explanations. Practical reports, on the other hand, require a more theoretical (imo) understanding of the chemistry behind the observations in an experiment, and writing skills become a pretty significant factor. There are often people who know the content back to front, but have difficulty explaining/communicating it on paper- so here’s some things that worked for me- organised into each “part” of a practical report.
Introduction: Here I provided a rather general summary of the investigation, defining through the specific context of the experiment the analytical technique for chemical process involved. In this sense, provide the experiment’s context by introducing the chemicals used as well. Personally my teacher liked introductions fairly to the point, and full of chemistry lingo. For our criteria sheet anyway, the intro was mainly for providing a brief preface, and wasn’t worth that many marks.
Example (from Unit 4 SAC 1 report-on Collision theory):
Spoiler
“Different reactions occur at varying rates, due to a range of contributing factors, which at an atomic level is explored through the Collision Theory. The collision theory dictates that in order for a fruitful reaction to occur, the reactant particles must collide, and with enough energy to overcome the activation energy barrier- the energy required to break reactant bonds so new ones can form. Thus the rate of reaction can be seen as the number of successful collisions in a given amount of time. The number of successful collisions is dependent on different factors; in this experiment the variables particle size, temperature, and concentration will be tested via an acid-base reaction between sodium hydrogen carbonate and citric acid, both which are ingredients in effervescent antacid tablets.”
Usually here all that’s required is a couple of sentences describing the practical’s purpose. Be direct and to the point. Not much to say here- often if your teacher hands out practical sheets (containing method and materials), on there is a quasi-aim I often just rewrote.
Example (from Unit 3 SAC 1b report- on Gravimetric analysis):
Spoiler
“To use gravimetric analysis to calculate the mass of sulfur as sulphate in a sample of Yates ‘Thrive’ fertiliser, and therefore verify the authenticity of their statement that their fertiliser’s sulfur content in their fertiliser is 17%.”
In science experiments, making predictions have a significant influence on how we view the science we are exploring. Our preconceived ideas of the chemistry (or biology or physics) can dictate what we are experimenting, and how the practical is structured. Thus while predictions are not an official (I only speak for VCE Chemistry as I studied it) section of a VCE Chemistry report, they are necessary in developing an insightful discussion into the concepts involved and the significance of our results- especially if one contradicts the other. We should also just appreciate that predictions or hypothesis are often the catalyst for performing these experiments, for example..
STORY TIME!:In the rigorous journey of deducing the structure of DNA, one stormy night in 1953 (ok- I don't really know if it was stormy, but for storytelling purposes just go with it
) scientists James Watson and Francis Crick analysed x-ray diffraction images taken of DNA, curious of its true structure.
Then they thought, through model building and other scientific knowledge, that DNA is a double helix, consisting of a phosphate based backbone and nucleotide "steps". Since they were clever cookies, they later published a paper suggesting that given the complementary nucleotide step pairing in the DNA double helix, one strand of the DNA molecule is used as a template that information is copied from. They also realised that Splash is bad at expression, and were angry that they could not hire literally lauren to do the storytelling instead.
"The hypothesis we are suggesting is that the template is the pattern of bases formed by one chain of the deoxyribonucleic acid and that the gene contains a complementary pair of such templates." (Source: James Watson and Francis Crick's 1953 Nature paper: A Structure for Deoxyribose Nucleic Acid)
It was this prediction, that gave birth to the experiment by Matt Meselson and Frank Stahl on DNA "semi-conservative replication"; the "most beautiful experiment in molecular biology". The experiment harnessed the power (i.e. differing weights) of nitrogen isotopes, bacteria cultures, and a lonely centrifuge, and after 13 years in Azkaban, scientific results were obtained- their hypothesis was correct.
Then the sun came out and fertiled the soils. The farmers cheered, and the butterflies danced amongst the gum trees... Everyone was happy, and it was all thanks to "predictions".
The end.
Back to a VCE perspective: For example, for the classic acid-base titration practical, we can predict to observe a colour change; based on our knowledge of how an acid-base reaction will potentially change the concentration of hydrogen ions, and thus the colour of the indicator. We can go further with our predictions too- consider some questions such as: "what would happen to the calculated concentration of an aliquot of NaOH(aq) if the burette was rinsed with water instead of the titre solution?"
Risk Management: Your teacher should provide you with a “Risk Assessment and Management summary table” if the experiment requires it. Here, you really just copy the codes and safety precautions from a given table- and for our class, we actually did this part of the report together in class (and the marks allocated were either full marks-for those who bothered to fill it out- or no marks- for those who didn’t bother).
Safety is the number one priority
I'm sure breaking bad would have ended much sooner if Walt didn't write his risk management forms when he was a student.
Here is an image of one of the forms I filled out (this one is from Unit 3 SAC 1):
Method: We were told to simply write “Please refer to procedure sheet for experiment”, but I do believe marks were deducted for those who didn’t write anything here- as it remains a component of the report.
Results: In the procedure sheet given, there should be an outline on how to best display your results. When writing results it is really important to present your work neatly and organised, meaning ruled lines, neatly drawn diagrams/visuals, and readable labels. In this sense, results can be very neatly displayed in tables (if applicable). Calculations should also be clearly set out, without skipped steps, and with correct symbols/notation.
Furthermore, it is often in this section that people would lose marks for incorrect scientific notation, whether it be incorrect state symbols, unbalanced equations, incorrect omissions of ion charges, no units, wrong number of significant figures, or omitting the word ‘ions’ when referring to ion reactant particles. It also helps to provide both qualitative (through observations) and quantitative (through calculations) results if possible.
Example (from Unit 4 SAC 1):
Discussion: This sections is where the marks really come from. Here, I would analyse my results, their credibility, and use these results to explain the chemical concepts explored by the experiment. Really show off your understanding of the chemistry involved here- but make sure your explanations agree with the results! Even better- use chemistry jargon in your explanations (you’ll find these words are rewarded with ticks when they are marked)!
I often broke my discussion into sections/paragraphs, depending on the experiment itself, and in each paragraph I would critically interpret what my results meant for that particular section. For further insight, I highly recommend also delving into the experiment’s limitations, and means to improve it next time.
Some questions to ask yourself when writing up the discussion:
Spoiler
You might consider answering questions like: (source: teacher's notes)
• What do your results mean?
• Are there common trends?
• Can inferences (explanations, deductions, conclusions) be made?
• Where there any unexpected or surprising results?
• Did you encounter any major problems while performing this practical?
• Did you have to modify the method in any way during the practical?
• How accurate is the data collected in this practical? How do you know this?
• Are there any aspects of this practical that will cause errors in the results?
• What sorts of things did you have to be especially careful of during the practical?
• Are there any things you could improve on if you were to repeat the practical?
• What are the limitations of doing the practical this way?
Example (Unit 3 SAC 2 report- on organic chemistry and chemical pathways):
Spoiler
“Overall, the range of tests did indicate each organic compound analysed had different and unique chemical properties, often due to their characteristic functional groups.
(first section on solubility) A solubility test was performed on all organic compounds analysed. The results have demonstrated that cyclohexane, cyclohexane, and 2-chloro-2-methylpropane all did not dissolve in water, but ethanol and ethanoic acid did. By analysing the chemical structure of both cyclohexane and cyclohexane, it can be seen that there are no components with largely differing electronegativity values and thus, the strongest forces within the molecule are dispersion forces- not strong enough to attract and be continuously surrounded by water molecules. While 2-chloro-2-methylpropane does contain greater intramolecular forces in a chlorine to carbon dipole-dipole bond, it is also not powerful enough to attract and be dissolved in water. This is largely due to the non-polar hydrocarbon chain the chlorine is covalently bonded to; there are too many non-polar components to change the molecule’s overall property to polar (in hindsight this could have been expressed much better).
Interestingly, however, the chloralkane did dissolve in ethanol, which can be explained by ethanol containing a polar component in its hydroxyl functional group, and a non-polar component embodying the rest of the molecule. Thus the non-polar component of the chloroalkane and ethanol are mutually attracted, and the polar components of both are also mutually attracted. The solubility of ethanol and ethanoic acid is due to their respective hydroxyl and carboxyl functional groups, which both contain oxygen that can hydrogen bond with the hydrogen in water molecules.
An interesting improvement would be to also test the solubility of larger alkaniols and carboxylic acids (e.g. decanol or nonanoic acid) to see if they’re still soluble, while testing smaller chloroalkanes such as chloromethane to see if it becomes soluble.
(second section on combustion) The next test was to test how well cyclohexane and cyclohexene could combust. The results clearly demonstrated cyclohexane undergoes complete combustion, meaning all carbon reacts with oxygen and all reactants formed carbon dioxide and water, evidenced by a clean red flame. Contrarily, cyclohexene revealed a dirty, black, sooty flame, signifying an incomplete combustion reactions, as not all carbon has reacted fully (e.g. could be carbon residue, or carbon monoxide). This suggests the two molecules react differently, at different rates, and produce different products, due to cyclohexane’s single carbon-carbon bonds, and cyclohexene’s carbon-carbon double bond influencing the proportion of the elements making up the molecule/s.
(third section on the ability different homogenous series have to undergo addition and substitution reactions)
The next test was performed on cyclohexane, cyclohexene, and 2-chloro-2-methylpropane to investigate their ability to undergo addition and substitution reactions. Bromine was added to cyclohexane and cyclohexene, but cyclohexane did not mix. Cyclohexene did mix however, indicating a different reaction occurred, which by analysing its chemical equation is revealed to be an addition reaction. It was only when cyclohexane was heated in sunlight that it reacted, evidenced by a colour change from red/brown to colourless. This was a substitution reaction as there is no double bonds in an alkane (all single bonds), so hydrogen must be displaced and substituted by bromine. This also shows substitution reactions require more energy to over and thus an improvement would be to test reaction rate between addition and substitution reactions at different temperatures. Contrarily, 2-chloro-2-methylpropane did not show any signs of a reaction, so instead, silver nitrate had to be added to the reacted solution to produce silver chloride- a white precipitate. Ultimately this form of evidence is indirect however, as the reaction was confirmed by the presence of these chloride ions as the precipitate. An improvement would involve ascertaining direct evidence; the reaction could be confirmed by the presence of methyl propan-2-ol, which could be done by analysing the product using Proton Nuclear Magnetic resonance spectroscopy. This is because 2-chloro-2-methylpropane would should one peak, representing one hydrogen environment, while methyl propan-2-ol would show two peaks.
(fourth section on esterification) After this an esterification reaction was performed, mixing ethanol with ethanoic acid to produce ethyl ethanoate.The reaction was confirmed by a strong smell, akin to nail polish remover, indicating the production of an ester. However, a more accurate alternative would be to use mass spectrometry to confirm the production of ethyl ethanoate, which would show a parent ion at a m/e ratio of 86, which signifies its molar mass as well.
(fifth section on ethanol undergoing a redox reaction) A redox reaction on ethanol was also performed, evidenced by a colour change from purple to yellow/brown. The ethanol was reacted with potassium permanganate, of which the ethanol was oxidised to form ethanoic acid. Thus it can be seen that a redox reaction can be used in reaction pathways to change the homologous serios a molecule belongs to, by changing its functional group. From the equation (in the results section) it can also be seen an acidic environment was required for the reaction to occur. However, like precious tests, the production of ethanoic acid from ethanol was only seen through the colour change of manages ions forming.Therefore a much better improvement would be to use an acidity test on the solution as ethanol is neutral and ethanoic acid is slightly acidic. Proton NMR and IR spectroscopy are also valid alternative. In proton NMR, ethanol will show 3 peaks while ethanoic acid will show two. In IR spectroscopy, ethanol will show a narrow O-H stretch at a wave number of around 3300 cm^-1 while ethanoic acid will show a much broader O-H stretch.
(sixth section on acidity) An acidity test, using coloured litmus paper was also applied to both ethanol and ethanoic acid, with the red and blue litmus paper maintaining their colours for ethanol, suggesting ethanol had a neutral pH. While the red litmus paper did not change for ethanoic acid, the blue litmus paper changed to red, indicating an acidic pH (<7). From this an acid-base reaction was performed, reacting the ethanoic acid with sodium hydrogen carbonate. The reaction was evidenced by bubbling-due to the formation of carbon dioxide. In this sense it can be seen that the hydroxyl functional group does not affect pH, while the carboxyl functional group makes the molecule more acidic. An alternative test would be to test the pH of ethanoic acid through a titration. It is also important to note that the previous reaction pathway altered the acidity of the molecule, by changing the molecule’s functional group via a redox reaction.”
(wow this was a long discussion- but hopefully it can act as a sample on a method of organising discussion ideas - for example note the improvements at the end of each section)
The conclusion really just brings the experiment to a close- a quick statement on the experiment’s success (did we achieve our aim?). It also helps to very briefly restate the main results of the practical- and what we gained/learnt from the practical.
Example (from Unit 3 SAC 2):
Spoiler
“Although some inference was required for tests with indirect evidence, the experiment successfully demonstrated that organic molecules of different homologous series contained different chemical and physical properties and could undergo different reaction types based on the functional groups they contained. The experiment also successfully showed how a reaction pathway can change the homologous series an organic compound belongs to, its functional groups, and its chemical and physical properties.
1. Write in a logical and organised manner- make it easy for your teacher to understand your thought process and explanations!
2. Use Chemistry jargon
3. Be critical and insightful in your analysis of the results
4. Be pedantic with notation and calculation accuracy (helps to set these out really clearly)
5. Use different mediums to display results (e.g. tables, graphs)- it makes it more readable
6. Really demonstrate your understanding of the concepts explored by the experiment
7. Try to give improvements/alternatives and critique accuracy of results
8. It may help to write in the 3rd person as it comes off as more professional (as far as writing a report for VCE goes)
9. If anyone has any other quick tips let me know and I’ll add them here![/li][/list]
Hope this helps!
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