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GCSE Science required practical's

For anyone doing AQA science, does anyone understand the chemistry paper 1 foundation required practical activity 9: that is based electrolysis
I've watched videos but I don't seem to get it anyway, can anyone explain what is supposed to take place?
is there a specific part that you dont understand (eg equipment, set up, process etc) so i can be more specific or would you rather go over the whole thing?
Yeah i just don't get the practical as a whole, and I don't really understand what the investigator during the practical is trying to look for.
Also the independent and dependant variable and the hypothesis.
Original post by Megan Bancal
Yeah i just don't get the practical as a whole, and I don't really understand what the investigator during the practical is trying to look for.
Also the independent and dependant variable and the hypothesis.

okay so you have an electrolyte which is either an aqueaous solution (something dissolved in water) or a molten substance (melted and kept really hot) and for based electrolysis its the first one.

in your electrolyte, you have an anode (positively charged, and where oxidation happens) and a cathode (negatively charged, and where reduction happens) which are joined to a cell (but you dont really need to know about that) the molecule(s) in the elctrolyte 9dissolved in the water) will split up and become ions. the negative ions will be attracted to the anode, and the positive ions to the cathode. the water molecules will also split up and the positive hydrogen ions will be attracted to the cathode and the negative hydroxide ions will be attracted to the anode.

Now, at the cathode, the ion which is LESS reactive will be 'sacrificed' and will undergo reduction, so you need to know the reactivity series to know whether the other ion is more or less reactive than hydrogen. if its less reactive, the metal will form around the cathode (you know its a metal beacuse metals form positive ions), however if hydrogen is less reactive, hydrogen gas will form and you will see bubble in the electrolyte**.

At the anode, if the ion is a halide, group seven, it will be produced as a gas. also, if the ion is simple(it has the number two or less in the subscript), it will be produced as a gas and for both of these you will see bubbles. however, if the ion is not a halide AND it is complex (if it has the number three or greater in the subscript) oxygen gas will be formed instead.

thats basically it. because the practical is about a productive process to create something, and not an experiment to observe something, there is no independant, dependant, or control variables, and you wouldnt be asked for a hypothesis for the same reasons.

the practical just isnt about looking for something, its about creating something.
** they might ask you how you could test/prove that the gas is hydrogen, in which case you would do the squeaky pop test.https://www.youtube.com/watch?v=4uqlaVTKy4U (link for a video on the test incase youre not sure what it is or how to explain it)

https://www.youtube.com/watch?v=GrgYXk_NCec this is the link for a cognito video on electrolysis of aqeous solutions And cognito now has a site where you can log in, choose your exam board, and see videos for bio chem and phys as well as past papers, exam questions and short recap quizzes that i find really useful

https://filestore.aqa.org.uk/resources/chemistry/AQA-8462-PRACTICALS-HB.PDF is the link for the teaching handbook for chemistry which gives you a rundown of all the practicals and is quite hepful for seeing what is required for you to know about each practical

im sure you will do really well and i wish you the best of luck for your gcse xxxxx
(edited 1 year ago)

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