Chemistry 🤦‍♀️

[BrokenWing]

ds has been looking for comparative data (table or graph) between electrolyte concentration and voltage for toooooo long, especially for a Friday night! I've tried for 30 mins (my Friday used to be more fun than this!) and now completely fed up.

Any chemistry buffs have any ideas where to find? It needs to be something he can quote as a reference.

<a class="break-all" href="https://www.google.com/url?sa=t&source=web&rct=j&url=www.sciencedirect.com/topics/engineering/electrolyte-concentration&ved=2ahUKEwjkntCC9fnmAhVhu3EKHThQBXMQFjACegQIDRAI&usg=AOvVaw12dEeU7GcA9fBDx3vlqJ44" rel="nofollow" target="_blank">Does this help?

Saw that page during my Google too, but need to pay to get into the article so can't use/reference, and the graph didn't make sense to us (we are expecting voltage to increase)

www.researchgate.net/figure/The-maximum-change-of-the-voltage-between-the-magnetized-and-nonmagnetized-iron_fig4_230625869

Saw that one too, apparently that's not the same experiment, that's something to do with magnetic iron which isn't relevant.

There are loads about temperature and voltage but concentration seems to be mentioned here and there but no data.

www.bbc.co.uk/bitesize/guides/z2396yc/revision/1

This?

www.bbc.co.uk/bitesize/guides/zjb2pv4/revision/3

www.bbc.co.uk/bitesize/guides/zpxn82p/revision/1

www.docbrown.info/page01/ExIndChem/electrochemistry01.htm

filestore.aqa.org.uk/resources/chemistry/AQA-8462-PRACTICALS-HB.PDF

And an experiment here- www.bydales.outwood.com/files/linked_files/7792/3fa78ec87974e46b299bff3c13377e92554b24b2?1465933170

He's ok with the underlying chemistry part, he needs comparative data in table or graph form. This is so he can do the experiment, then use the data to compare with and analyse the results as part of his report.

We have a homework corner?

Which exam board?

It’s a bit hard to say without the context. It sounds like electrochemistry but we would need to know which electrolyte and probably which electrode. What level is this?

It's Scotland NAT5, electrochemistry, so fairly basic. He knows the chemistry, knows how to do the experiment.

Doesnt have to be the same electrode (he hasn't done the experiment yet to can decide that next week, will probably be copper and either zinc or alu). Just needs to be some data with different concentration and voltage measurements showing a trend to compare his results with.

Teacher set it, so would think there world be something somewhere!! I just can't find it. Thought I must be putting in wrong searches (as I didn't do chemistry at school 35 years ago!)

I think you might be looking for the reactivity series

Is this helpful? qualifications.pearson.com/content/dam/pdf/A%20Level/Chemistry/2015/teaching-and-learning-materials/A_level_Chemistry_Core_Practical_10_-_Electrochemical_Cells.pdf

Electrochemistry doesn’t actually appear on the English syllabus until a level

Because the concentration shouldn’t make a difference to the voltage (provided it’s concentrated enough). The voltage/current is determined by the difference in reactivity between the two metals (how easily it is to turn atoms in the electrode to ions in solution and vice versa).

Just as a heads up, I would do copper and zinc as it’s fairly foolproof, while the aluminium forms oxide very quickly in air which will affect the results. The other metals need to be polished ahead of the experiment though.

It's not the english syllabus. Its Scottish Nat5. Dont remember dd doing that for her chemistry Nat5 last year

I know it’s not the English syllabus, but the resources I’ve provided are from A level because electrochemistry doesn’t really appear until then in England. (I know this because a significant part of my job is electrochemistry public engagement)

You could try posting in Scotsnet

Or he could speak to his teacher

We are expecting the concentration to change the voltage, unless he's been looking at the wrong stuff...

www.enotes.com/homework-help/galvanic-cell-you-change-concentration-one-307505. He's got information etc on why so that's all OK I think. It's just a comparison data source he needs

Speaking to the teacher is difficult, the usual teacher is on paternity leave and they have been having non-chemistry teachers for 2-3 weeks and he thinks they are to do the experiment next week 🤦🏻‍♀️

Ok so it’s a Galvanic Cell (or sometimes called a Daniel Cell). I’ll admit I don’t usually change the concentration when I show this experiment, but I use it for a different reason, to show something else. I’m going to pop some YouTube videos below. They might have the answer but I haven’t watched them because I have a small child asleep next to me.

m.youtube.com/watch?v=ByjXf1kEatM

m.youtube.com/watch?v=g2k9R_5A0w0

This may also help:

pennyroyalresearch.files.wordpress.com/2017/01/the-effect-of-temperature-and-concentration-on-galvanic-cells.pdf

I’ve done a bit of searching and I can’t find a table of values for the concentration effects

• the closest is a graph in that document above which appears to be another student’s work. It’s freely available online but you should have a chat about plagiarism if you’re going to use it.

I think that the information you’re looking for is usually experimentally derived, so you set up your cell, vary the concentration and then get the answers you’re looking for that way. The maths behind the effect is the Nernst equation which is reasonably complex, I don’t think it appears pre-undergraduate bit I don’t know, I’m not a teacher. The maths is all laid out on the internet but i don’t know whether it’s accessible in terms of content, it’s not that complex for, say an A level maths student or even maybe a GCSE student depending on whether they are comfortable with logarithms

Thanks for taking the time to look raindrops, you've found all the links I did and confirmed ds and I'm not missing anything . It's really frustrating, the equation side of things (Nnerst, equilibrium etc) they haven't been taught and are much more than a NAT5 student would expect to do so that's not relevant.

Found this on the SQA site:

In circumstances where there is difficulty in locating secondary data/information, teachers and/or lecturers may provide candidates with a wide list of URLs and/or a wide range of books and/or journals. (A wide list is specified as a minimum of six.) This list must have a sufficient range of sources to allow candidates to make decisions about which data/information is relevant.

I'm going to send him back to the teacher and if they isn't any teacher available then the head of department. If the comparison isn't available they need to tell him what he should do. This report counts towards 20% of their final exam, and the teacher set the topic so they can tell us where the info is!! I am thinking the teacher had chosen a set of topics for them without actually checking there is data available.

Yes, if it’s there it’s not easy to find! Are you sure he has the idea right? That he’s meant to have the information before doing the experiment? Whatever the answer to that, it sounds like the work has not been set with sufficient instructions.

I originally thought that the experiment would be to set up the galvanic/Daniell cell and use a variety of different metals/electrolytes to show the reactivity series. I think you probably do need to go to head of dept actually because this is important to fix