| Question 1 |
(a) I was looking for one of the following: EITHER you should have picked a KBr pellet (because no interfering peaks, unlike nujol, which has interfering peaks. OR you could have picked to run as solution form, but has to point out that there can't be any overpapping lines (solvent would have to exclude C-H peals, for example). |
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| Question 1 |
(b) For a hydrocarbon like this, it can relax
all the way via vibrational relaxation, because the electronic energy levels
are close together (and therefore the vibrational envelopes overlap). |
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| Question 2 |
Absorbance from compound 1 = (4.62 x 103)(3.68
x 10-5) = 0.170 Absorbance due to compound 2 is, then, 0.534-0.170 = 0.364 Concentration of compound 2 is (0.364) / (1.27 x 103) = 2.87 x 10-4 M |
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| Question 3 |
Remember to use the spiking (method of standard addition)
formulae: cu = bcs/mVu = (0.28005)(10.00) / (0.048514)(5.00) = 11.545 --> use volume of unknown added (5 mL), not total volume (25 mL)! Su = -(cu/x-intercept) (Sr/m) (1/N + y2/m2Sxx)1/2 [where y is the average y value = 0.4013] = 0.217 Therefore, unknown should be reported as 11.5 +/- 0.2 ppm. |
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Last updated, February 15, 2006
Page maintained by Craig MacKinnon