ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: crawlingvines on October 20, 2018, 11:12:54 pm
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I've gotten through a good chunk of practice exams now and the one topic I'm consistently losing marks on is electrolysis. I'm fine with calculations and theory-based questions but when it comes to writing half-equations for never-before-seen cells, my brain pretty much implodes on itself.
An obvious remedy is practicing writing half-equations but I'm really struggling to develop my own technique when it comes to quickly digesting what reactants are involved and their oxidative/reductive strengths. Any tips?
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I've gotten through a good chunk of practice exams now and the one topic I'm consistently losing marks on is electrolysis. I'm fine with calculations and theory-based questions but when it comes to writing half-equations for never-before-seen cells, my brain pretty much implodes on itself.
An obvious remedy is practicing writing half-equations but I'm really struggling to develop my own technique when it comes to quickly digesting what reactants are involved and their oxidative/reductive strengths. Any tips?
I also have issues with this and have decided to simply memorise some cells.
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I find labeling everything i can get my hands on helps quite a bit. for example if an equation for discharging at the cathode is given i label it in big lettters "DISCHARGE REDUCTION", therefore when it comes to recharging i know instantly that it becomes "RECHARGE OXIDATION" and oxidation always occurs at the anode. another great rule is strongest oxidising and strongest reducing always react. i know its simple but its not as intuitive as you may think. When i see the word solution i write in big letters "H20". Ussully vcaa loves mixing up the equations, writing the the oxidation reaction on top of the reduction reaction. a move which is counter intuitive to students, as the Electrochemical series shows something else, i recommend re-writing it in a way which suits you. also make sure to keep an eye out on electrolytes common ones include acidic (h+ions and oh- ions) be sure to include that when writing up any equations. VCAA are very pedantic about electrolysis and redox, as differing from the answer is easy but detrimental.
TL;DR vcaa understands the way we all think, their aim is too mess with any pre-held intuitions. label everything and re-write it to suit your needs. :)
I've found it useful to make a table like this
(https://i.imgur.com/KdZGxkG.png)
During questions. Ensures i don't mess up. Obviously without the colours tho.