Industrial Chem ?! (1 Viewer)

[FCB]

^exactly what i had bar the fact i dont think i had added it was concentrated

The answer is in the texts bookssss..

 

[jamesfirst]

It was 3 marks, 1 mark for naming, 1 mark for explanation, 1 mark for chemical equation. So maybe/maybe not.

Hey if I said that copper sulfate's colour thickens do I lose a mark ???


I dont know why I talked about the actual colour........

 

[umz93]

Is it true you get marks for crossed out answers? I had dehydrating agent but changed it to oxidising agent :S

 

[Midnight_Lotus]

I emailed my teacher about the question and this is what he said:



The dot point that it is most likely coming from is:
· perform first-hand investigations to observe the reactions of sulfuric acid acting as:
an oxidising agent
a dehydrating agent

and possibly:
· outline three uses of sulfuric acid in industry

Sealed container – no excess moisture from the air

Copper sulphate pentahydrate –is blue in colour
Copper sulphate – anhydrous – is white in colour
(this is the bit of chemical knowledge that I suspect is a stretch – its not a prac which is specified in the syllabus – it is typically done in about year 8!)

I would predict that liquid X is sulphuric acid and the process being modelled is using it as a dehydrating agent.

I’m not sure what type of chemical equation would be suitable as its what I would class as a physical change, but “bonds” are being broken so it could be represented as

CuSO4.5H20 -> CuSo4 + 5H20

 

[Username2]

Well tbh I thought it was NaOH at first because its hygroscopic. Was wrestling with it for a while because NaOH production is also in Industrial Chem but wrote down H2SO4 cause I remember doing the prac and thought it was the only sensible answer- even though I didnt understand what was actually going on.

 

[weber]

This is exactly, 100% correct. I just looked it up: http://www.finishing.com/173/41.shtml (and also cross-referenced)
Thats not general knowledge, how did you know the whole equation + colour change??

It is general knowledge that most solutions of copper are blue. Hydrous CuSO4 is sort of like in solution so they're blue crystals. Conc. sulfuric acid being a dehydrating agent does exactly that. So for the equation, you'd make CuSO4 anhydrous. I don't know if you could have added H2SO4 (l) into the equation as well and have the product include H2SO (aq). CuSO4 (s), I guess you needed to have done the experiment to have gotten white. Most precipitates are white though so that's probably the best guess.

Don't fret, I didn't know the answer until I realised what experiment it was after the exam. I was thinking how the hell is something supposed to happen if they're not being reacted together. I vaguely remembered CuSO4.5H2O in my mind but no idea from there.

 

[shakky]

I showed my chem teacher the question and she said it was water?
I think shes wrong though
I was wtf all the way home that first question got me so confused Im only expecting a 17/25 I hope it aligns to 20 or something because I hear people found the other options easy....

I put down water, but its wrong. Silly me didn't bother to read the question and see that it was pentahydrate, so it was actually donc. sulfuric acid. Does anyone think i will get atleast 1 mark for the equation and explanation (like error carried forward- lol)