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JC Chemistry practical can be really exciting, albeit very stressful too. If you hope to do well for your upcoming practical exams, it would great if you could heed some of the advices below 🙂
Practical is primarily a test of your ability to follow instructions, pay attention to detail, and handle the apparatus safely. It is advisable to read all the steps carefully before you start the experiment. Reading through all the steps beforehand would ensure that you are well aware of everything you’ll need to do subsequently. You should ensure that you have all the apparatus you need.
For those who would like to take up the challenge of reading the instructions as you do the experiment, you’ll be in for an exciting session! You’ll probably be having a race with the magnesium ribbon, to see if it can dissolve faster than you transferring solutions from a measuring cylinder to a beaker.
Before the practical commences, you will definitely be given at least 5 minutes to do your washing. Make sure that you make good use of this time to wash EVERY single apparatus properly. Using a dirty/contaminated apparatus would affect your results and findings.
Titration would be most frequently conducted in JC. By the time you sit for your practical exams, you would have washed countless burettes and pipettes! Admittedly, it can be quite troublesome to wash burettes and pipettes as they need to be first washed with tap water, followed by deionised water and then the solution (and that’s not just 3 simple steps/gestures).
*Remember: DO NOT wash the conical flask with the solution! Deionised water only!!
Some students try to cut corners by skipping the deionised water step. However, doing so could compromise on the accuracy of the results. In other words, it is best not to risk it. Complete all the necessary washing steps so that your reading would be as accurate as possible.
You wouldn’t be penalised for an untidy bench, but you’re just short-changing yourself in ways that you didn’t realise. A tidy bench implies that every apparatus is in its own place and have been arranged in such a way that is convenient for you. Having proper organisation reduces the chances of you breaking any glassware, especially if you happen to be handling multiple apparatus all at once. If you are not careful enough, you might just unknowingly knock down something with your hand.
And as the apparatus attempts suicide and shatters into smithereens, your heart shatters in a similar fashion
You’ll need to be super careful and patient when it comes to titration! Normally, the first titration enables you to get a rough idea of the volume that should be released from the burette for complete neutralisation. That means that you don’t have to be that careful yet for the first titration.
After knowing the rough estimate of the volume required, do a quick release followed by dropwise near the “end mark”. The dropwise step must be done very carefully while you observe the colour of the solution in the conical flask. One drop too much and you may have to redo.
Ideally, it’s best if we could obtain two readings which are less than 0.10cm3 apart in just 2 tries as it will definitely save us a lot of time. However, when your results are questionable, you would probably want to try until you obtain two readings with a smaller difference between them. Otherwise, you may say goodbye to your accuracy mark too.
Other things to take note of:
- Do not leave the funnel in the burette after transferring the solution from the bottle into the burette.
- Read from the meniscus level when the solution in the burette is transparent. If KMnO4 is used, read from the fluid level instead.
Lighting up the Bunsen Burner
Pretty basic skill, but most people don’t pay enough attention when it comes to lighting the bunsen burner. How many of you actually ensure that the air hole is closed before lighting to prevent a strike back? Without having to survey the class, I can safely say “not many”. However, it is always important to practice “safety first” in the lab. Ensure that you don’t endanger yourself or anyone around you as you are conducting experiments.
When you are heating up a test tube, be sure to point the test tube away from your friends so that they would not be a victim of the spurts if the reaction becomes too vigorous.
Attention to detail
There are many nitty gritty details that you may close one eye to whenever you conduct experiments. However, it is these little things which would affect the overall result and data collected from your experiment. Therefore, when the instructions do highlight certain steps that you need to take, try your very best to fulfil them. Things such as “drying your beaker completely before adding solution x” and “using a 10cm3 measuring cylinder (in particular)” to transfer solution y to a 50cm3 beaker should be taken seriously and done to the best of your abilities.
Chemistry is all about the colour!
You’ll need to have a good eye so that you can correctly identify the colour and state of the substances and record your observations in a clear and concise manner. You’ll need to ask yourself questions like “Is this dark enough to be considered dark blue” and “Is this partially or fully soluble?” whenever you’re conducting Qualitative Analysis Experiments. If you don’t exactly know what the ideal/benchmark colour is, remember to make use of your usual practical lessons to find out from your teacher. Don’t be afraid to ask, or you’ll never learn! Try to remember the colours that you’ve seen as well so that you can identify them more easily in future!
Go for a colour vision checkup!
Now this is important. Perhaps you’ve always wondered why your titration results are always slightly off from the “model answer”. No matter what, go for a colour vision checkup. This is especially important as you’re dealing with small changes in colour shade in titration, and any colour deficiency can make the difference between a wrong titration result and a correct result.
If you discover you have a colour vision issue that can affect your practical work, get a doctor’s report, and apply to MOE for the appropriate assistance. Remember that MOE’s will take time to process and approve your application, so apply early!
Learning Chemistry at XMEducation
These are just some of the tips and tricks that you should know about in preparation for your practical exam. At XMEducation, we cover more than just theory in H2 Chemistry, as we do acknowledge that practical can be quite a difficult component as well. Not to worry though, because Chemists have all the solutions! (geddit?) Our Chemistry tutor, Miss Alice, has designed a comprehensive chemistry practical guide with all the useful planning and practical tips! Sign up here for a free trial class to find out about our teaching methods and how you can ace your chemistry today!