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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: NE2000 on September 15, 2009, 07:23:36 pm

Title: Colours of substances
Post by: NE2000 on September 15, 2009, 07:23:36 pm
Alright, basically I was doing a chem paper and they said an electrolytic cell formed a red-brown colour around one electrode and it asked what was being formed. So what coloured substances should we be able to identify by colour?
Title: Re: Colours of substances
Post by: Gloamglozer on September 15, 2009, 07:30:39 pm
Red-brown is iron I think.
Title: Re: Colours of substances
Post by: shinny on September 15, 2009, 07:31:15 pm
From memory, pretty much just that one. The bromine test is something you should've learnt about either in a textbook or a prac. Flame colours (e.g. sodium yellow, chlorine green etc) might also be tested but I don't recall there ever being a question on it.
Title: Re: Colours of substances
Post by: NE2000 on September 15, 2009, 07:38:34 pm
CuSO4 is blue, I think we're meant to know that.

The bromine test decolourizes unsaturated hydrocarbons that's all good but I don't think they'll ask that or the flame colours in Unit 4.

By the way the answer was bromine forming...
Title: Re: Colours of substances
Post by: shinny on September 15, 2009, 07:40:30 pm
CuSO4 is blue, I think we're meant to know that.

The bromine test decolourizes unsaturated hydrocarbons that's all good but I don't think they'll ask that or the flame colours in Unit 4.

By the way the answer was bromine forming...

Oh yes, you're in unit 4 now. And well yeh, I guess copper sulfate is another standard one. Still can't recall any other common ones though. If you've been paying attention in pracs, you should be fine though.