Chromatography Assignment Last Question (Which isn’t shown) is HOW MANY microgra
ID: 541871 • Letter: C
Question
Chromatography AssignmentLast Question (Which isn’t shown) is HOW MANY micrograms (ug) OF COPPER ION ARE IN THE SPOT? ____ ug
I need all questions done. Thank you. PRE-LABORATORY ASSIGNMENT for CHROMATOGRAPHY Hypothetical Chromatogram 8 -Solvent Front line 7 6 5 4 3 2 Spotting line 0 2) It takes about 3.08 L (microliters) of a copper solution containing 0.639 g of copper ion per 100 mL. to make a spot approximately 0.305 cm in diameter. Calculate the micrograms of copper ion in the spot. Using the "ruler" in the picture of the chromatogram and measuring with an accuracy of.1 unit, calculate the retardation factor (Re) for compound.. C. MEASUREMENTS AND CALCULATIONS la) How far did compund C move? lb) At the same time, how far did the solvent move? 1c) What is the Rr for compound C? "units" "units".
Explanation / Answer
Ans. #a. Compound C moved 4.50 cm.
#b. The solvent move 5.80 cm (the distance of solvent front from baseline).
#c. Rf for compound C = Distance travelled by C / Distance travelled by solvent
= 4.50 cm / 5.80 cm
= 0.78
#4. Quantification:
Given: It takes about 3.08 uL of Cu solution containing (0.639 g copper ion / 100 mL) to make a sport of 0.305 cm in diameter. It serves as standard.
Total mass of Cu in standard spot = [Cu2+] x Volume of Cu-solution taken
= (0.639 g / 100 mL) x 3.08 uL ; [1 uL = 10-3 mL]
= (0.639 g / 100 mL) x 0.00308 mL
= 0.0000196812 g ; [1 g = 106 ug]
= 19.68 ug
Area of the standard spot (assumed to be circular) = (pi) r2
= (pi) x (0.305 cm / 2)2
= 0.073062 cm2
Therefore, a spot area of 0.073062 cm2 is equivalent to 19.68 ug Cu2+
Or, standard [Cu2+] in the spot = 19.68 ug Cu2+ / 0.073062 cm2
The amount of an analyte in a spot is proportional to its area.
# The diameter of spot is NOT mentioned.
Let’s assumed it to be 0.360 cm. [you shall you the correct value given to you].
Area of the new spot = (pi) x (0.360 cm / 2)2 = 0.101788 cm2
Now,
Amount of Cu2+ in new spot = [Cu2+] in standard spot x Area of new spot
= (19.68 ug Cu2+ / 0.073062 cm2) x 0.101788 cm2
= 27.42 ug
Note: You the correct diameter of spot given to you.
If not, seeing spot C in this picture, you shall preferably use graph paper to determine the approximate area of the spot C. The calculate Cu-content in it as described above.
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