Review the Learning Resources I attached as file before answering the discussion. Then, post your original posting and thoughtfully.Provide an example of some form of misrepresentation in media over

1. After application of anion exchange resin, the activity of Tc-99 in the initial solution dropped from 1000 Bq/mL to 10 Bq/mL.

1. What is the distribution ratio of pertechnatate (TcO4-) for this resin?

2. What is the decontamination factor for this procedure?

1. For determination of uranium activities by alpha-spectrometry of electrodeposited samples, the yield of electrodeposition procedure has to be determined: the solution of depleted uranium (~100% U-238) of 30 mL was placed into an electrolysis cell and spiked with U-239 (beta 1.265 MeV, T1/2= 23.5 min). After 70-min the initial activity of U-239 in that solution dropped from 480 dpm/ml to 20 dpm/mL. Assume negligible changes of volume by spiking and during deposition, and calculate:

1. What is the deposition yield of uranium?

2. What amount of the analyzed U-238 was deposited on the planchet if the concentration of the analyzed sample was 60 Bq/mL?

3. What count rate will be counted with a 40%-detection efficiency of the alpha-spec system?

1. With the aim to minimize the volume of a biochemical laboratory waste, which was practically a radiolabeled sulfuric acid (H235SO4), it was treated to precipitate it as a barium sulfate: to 10 L of 0.1M solution of H2SO4 with activity of 37 Bq/0.1 mL, a stoichiometric amount of Ba (as barium chloride) was added.

1. What activity of 35S remained in the supernatant solution given that the solubility product of BaSO4 is KS = 1x10-10 mol2/L2?

2. What was the efficiency of the decontamination/precipitation procedure?

1. For determination of the solubility of lead iodide (PbI2) in water, a 212-Pb (T1/2=10.4 hr) radiotracer was added to a sample of PbI2 in such a way that the specific count rate of the spiked sample was 59 cpm/mg. After 10 hrs of agitation of the sample in 1L of water, a 10-mL aliquot of the saturated solution showed 226 cpm. Find the solubility of lead iodide in mg of PbI2 in 100 mL of water.

HINT:

Decontamination factor (or efficiency of decontamination procedure) is the ratio of the initial and final concentrations:

DF = Cfinal/Cinitial

Fraction of removed: = (Caq, init –Caq, final)/ Caq, initial x 100% (the same for yield)

Distribution ratio is always ratio of equilibrium (final) concentrations on interface:

• For liq-liq interface (solvent extraction):

D= Corg phase/CCaq phase = (Caq, init –Caq, final)/ Caq, final ->[Bq/mL]/[Bq/mL]= no unit

• For solid/liq interface (sorption, ion-exchange):

D= = Csolid/ Caq, final = (Caq, init –Caq, final)/ Caq, final = [Bq/g]/[Bq/mL]= [mL/Bq]