Zinc oxide and Cu

lepton_index · 16 Sep 2004, 2:50 PM

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Syllabus point: Explain the relationship between absorption and reflectance spectra and the effect of infra-red and ultra-violet light on pigments including zinc oxide and those containing Cu

I'm fine with explaining the relationship between absorption and reflectance spectra --- but I can't find any information on ZnO and Cu effect. Please help,

Thanks

tomorrows_angel · 18 Sep 2004, 7:17 AM

i haven't actually looked yet, but www.hsc.csu.edu.au, the charles sturt uni site, has just updated their options so now there is info on the chem of art... you could try that. hope it helps.

randhi · 18 Sep 2004, 9:03 AM

Okay this is some stuff from my notes:

- IR(heat) can change the colour of zinc oxide in the presence of oxygen from white to yellow. Copper(I)Oxide (red) turns to Copper(II)Oxide (black).
- TiO2 a white pigment doesn’t change colour.
-Infrared spectra utilizes a ceramic heat source to pass IR through a sample and solvent, and then compare the relative intensities, which allows the absorption of radiation to be determined. IR changes colour of ZnO2 in the presence of O2 from white when cold to yellow when hot. Cu2O goes from red to black CuO.

nit · 18 Sep 2004, 11:41 AM

Some other things you could talk about are copper tetraammine and how the concentration of a solution of this may be determined by shining uv at it, since absorbance is directly proportional to concentration...ie uv can be used for quantitative measurements of a copper solution; for infra-red radiation, you could possibly mention emerald green (containing copper and arsenic) that absorbs some ir wavelengths and hence shows up dark when infrared radiation is shone at it, and the reflected ir recorded by some type of data-logger.

lepton_index · 28 Sep 2004, 2:00 PM

Thanks. I got it. And just a quick note: for the "explanation" bit: Bbcause the electrons in the Zn and Cu atoms absorb UV / IR, so their electron configuration in the outermost shell are changed, thus they change colour.
E.g.: Zn is white when cold, because its outermost shell is filled. But it is yellow when hot - indicating that the 3d subshell is not fully occupied.

16 Sep 2004, 2:50 PM	#1 (permalink)
lepton_index New Member HSC: 2004 Gender: Undisclosed Location: Newcastle Join Date: Feb 2004 Posts: 16 Last Activity: 20 Feb 2006, 12:13 PM	Zinc oxide and Cu You can hide this advertisement by registering. Syllabus point: Explain the relationship between absorption and reflectance spectra and the effect of infra-red and ultra-violet light on pigments including zinc oxide and those containing Cu I'm fine with explaining the relationship between absorption and reflectance spectra --- but I can't find any information on ZnO and Cu effect. Please help, Thanks

18 Sep 2004, 7:17 AM	#2 (permalink)
tomorrows_angel tomorrow is too soon... HSC: 2004 Gender: Female Location: Hills District Join Date: Mar 2004 Posts: 741 Last Activity: 1 Aug 2008, 8:28 PM	i haven't actually looked yet, but www.hsc.csu.edu.au, the charles sturt uni site, has just updated their options so now there is info on the chem of art... you could try that. hope it helps. __________________ ~* On ne voit bien qu'avec le coeur. L'essentiel est invisible pour les yeux. *~ Bachelor Of Education (Primary Education) at the University of Sydney

18 Sep 2004, 11:41 AM	#4 (permalink)
nit Exalted Member HSC: 2004 Gender: Male Location: let's find out. Join Date: Jun 2004 Posts: 839 Last Activity: 1 Oct 2008, 7:31 PM	Some other things you could talk about are copper tetraammine and how the concentration of a solution of this may be determined by shining uv at it, since absorbance is directly proportional to concentration...ie uv can be used for quantitative measurements of a copper solution; for infra-red radiation, you could possibly mention emerald green (containing copper and arsenic) that absorbs some ir wavelengths and hence shows up dark when infrared radiation is shone at it, and the reflected ir recorded by some type of data-logger. __________________ SGS Class of '04; UAI:99.95 Combined Science Medicine:BSc(Adv)/MBBS Tutoring available for HSC Mathematics 3U/4U; Chemistry; Physics. For more information please visit: http://community.boredofstudies.org/...82#post2049682

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18 Sep 2004, 9:03 AM	#3 (permalink)
randhi Member HSC: 2007 Gender: Male Join Date: Mar 2004 Posts: 177 Last Activity: 6 Jun 2006, 6:19 PM	Okay this is some stuff from my notes: - IR(heat) can change the colour of zinc oxide in the presence of oxygen from white to yellow. Copper(I)Oxide (red) turns to Copper(II)Oxide (black). - TiO2 a white pigment doesn’t change colour. -Infrared spectra utilizes a ceramic heat source to pass IR through a sample and solvent, and then compare the relative intensities, which allows the absorption of radiation to be determined. IR changes colour of ZnO2 in the presence of O2 from white when cold to yellow when hot. Cu2O goes from red to black CuO.

28 Sep 2004, 2:00 PM	#5 (permalink)
lepton_index New Member HSC: 2004 Gender: Undisclosed Location: Newcastle Join Date: Feb 2004 Posts: 16 Last Activity: 20 Feb 2006, 12:13 PM	Thanks. I got it. And just a quick note: for the "explanation" bit: Bbcause the electrons in the Zn and Cu atoms absorb UV / IR, so their electron configuration in the outermost shell are changed, thus they change colour. E.g.: Zn is white when cold, because its outermost shell is filled. But it is yellow when hot - indicating that the 3d subshell is not fully occupied.