Unit 1 Notes STAT-1000 earning.ca/ibiscms/mod/ibis/view.php?id 216724 M 1300 Lec
ID: 494732 • Letter: U
Question
Unit 1 Notes STAT-1000 earning.ca/ibiscms/mod/ibis/view.php?id 216724 M 1300 Lecture & Winter 2017 I Activities and Due Dates I pre-Lab 4 Not set A 892/100 G 3/11/2017 11:57 PM te Print Icalaulator Gi Periodic Table Question 11 of 12 G Sapling earning An unknown amount of a compound a gmol is in a 10-mL ou flask of this solution is transferred to a volumetric flask and water is added to dilute to the mark. The absorbance of this diluted solution at 355 nm is o 427 in a 1 cuvette. The molar absorptivity for this oompound at 355 nm is eass 5571 M cm 1 (a) What is the concentration of the compound in the cuvette? (b) What is the concentration of the oompound in the 10-mL flask? (c) How many milligrams of compound were used to make the 10-mL solution?Explanation / Answer
Beers law is given by, A = ecl
=>c = A/el and since l=1
=>c = A/e
(a) c = 0.427/5571 = 7.66 x 10-5 =76.6 x 10-6 =76.6 uM
(b) Overall dilution is 1:25, therefore concentration in original 10 ml = 25 x 76.6 uM = 1.92 mM
(c) 1.92 mmol/L x 0.01 L x 276.52 mg/mmole = 5.3 mg
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