18-18 form then in atmospheric ozone at different latitudes. Dsa Beer\'s Law in
ID: 557050 • Letter: 1
Question
18-18
form then in atmospheric ozone at different latitudes. Dsa Beer's Law in Chemical Analysis 1-17. What is the purpose of neocuproine in th 18-18. A compoun compound with molecular mass 292.16 g/mol was dis- a - volumetric flask. A 1.00-mL aliquot was with- in a 10-mL volumetric flask, and diluted to the mark. -mL The absorbance at 340 nm was 0.427 in a 1.000-cm cuvet. The molar absorptivity at 340 nmis 340- (a) Calculate the concentration of compou (b) What was the concentration of = 6 I 30 M-1 cm-i nd in the cuvet compound in the 5-mL flask? (c) How many milligrams of compound were used to make the 5-mL solution? 18-19. If nse in a 1-cm cell. Will the absorbance of the reagent-blank solu- I a sample for spectrophotometric analysis is placed in a cm cell, the absorbance will be 10 times greater than the absor-Explanation / Answer
(a) A=ebc
c=A/eb
c=0.427/ (6130 x 1)
c= 6.97*10^-5M
(b) not all of the 5.00 mls of stock was diluted , only
1.00 ml of the stock solution was diluted up to 10 ml
c1v1=c2v2
c1(1.00mL)=(6.966*10^-5)(10.00ml)
your answer is: c1=6.97*10^-4 M
is the strength of the one ml taken from the 5ml stock, & the strength of all of the mls in the 5ml stock as well
which changes the next
6.966*10^-4mol/L x 292.16 g/mol x 1000mg/g =203.52ppm
your answer: 204 mppm
(c)
you have the 6.966*10^-4Molarity & 5 ml's...
we could calculate the moles,:
0.005 litres * 6.966*10^-4 mol/litre = 3.483*10^-6 moles
then use the molar mass to calculate the grams used"
3.483*10^-6 moles * 292.16 g/mol = 1.0176*10^-3 grams
your answer is 0.00102 grams of stuff
or you can use the 204 ppm , which is milligrams / litre , to find the grams in 5 ml..:
0.005 litres * 203.52 mg/litre * (1g/1000mg) = 0.0010176 grams
your answer:0.00102 grams of stuff
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