Good idea for Chem investigation?

Right so I have this general idea for investigation.
I was thinking I was going to do my inv on determining the mass of copper in coins. I was going to do it over say, 30 years and see if the mass of copper present in coins have decreased over time. See if the value of copper exceeds the represented value and by how much.
However my teacher (one already approved it sayin g its been done before and is suitable), asked me what techniques i am going to use to make it advanced higher level.
If i did it, it most likely (although the exact methods i have not worked out):
-dissolving using super strong acid (10M)
-colorimetric anaylysis of some sort-doing a calibration curve?
-titrations
-maybe throw in some atomic spectroscopy for the hell of it?
What do you guys think?

Reply 1

TheRabbit

24craigour

A guy in my class did this, he used very strong nitric acid to make blue copper nitrate solution which he did colorimetric anaylsis on. It seemed to work fine, though because the fume cupboard was broken he had to stick the beaker he was dissolving the copper in outside the window :biggrin:

He compared coins from a few different years and only did it using that one method as far as I know.

If you can find somewhere (a university) then you could do some kind of atomic spectroscopy - I used ICP spectroscopy to find how much iron was in an iron tablet.

Reply 2

LeeLee---x

My pal did this, she did colorimetric analysis and titratons, seemed to work fine for her.

Reply 3

Aurora.

I did something like this. Volumetric and colorimetric analysis, and the other person I know who did something similar (but didn't procrastinate so much and had loads more time to do it in) threw in some atomic spectroscopy just for the hell of it. It works, and definitely enough for Advanced Higher.

Reply 4

24craigour

[QUOTE=Aurora.]I did something like this. Volumetric and colorimetric analysis, and the other person I know who did something similar (but didn't procrastinate so much and had loads more time to do it in) threw in some atomic spectroscopy just for the hell of it. It works, and definitely enough for Advanced Higher.
..... :ninja:

have you still got your investigation so i can see your method? Just the method as i'm not sure how to plan it first...
I would be your eternalslave :beg:

Reply 5

Aurora.

I don't

I'm sorry, and I could really use an eternal slave too, but my teacher got the spare paper copy and I've lost my memory card.

What is it you're not sure about? I may be able to help a bit... Maybe...

Reply 6

Aurora.

I used this to get the basic idea and I was planning on doing this experiment originally...
http://www.creative-chemistry.org.uk/alevel/module5/documents/N-ch5-17.pdf

But because the reaction forms a precipitate it's a nightmare trying to detect the colour change so you can't really determine the end point all that well.

Ah! I've just had a trawl through my computer and I've got some of it saved there, just the preparation of the coin solution and the volumetric bit. PM me your email address and I'll send what I've got, if you want?

Edit: Forgot. Because the volumetric didn't work I ended up doing gravimetric for this bit. I did a pound coin... Ah! Found another copy with everything but the colorimetry :P