The radioactivity of a sample of 11C is reduced from 1 Ci to 711 mCi in 10 minutes. Calculate the decay constant.
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0.015 min-1 |
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29.318 min-1 |
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28.900 min-1 |
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3.411 min-1 |
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0.034 min-1 |
The radioactivity of a sample of 11C is reduced from 1 Ci to 711 mCi in...
1. For a first order decay of [A], if 525 mg remains of an initial sample of 1.3079 g after 361 min, what is the half life (in minutes)? 2. The decay of antimony-131 is first order with a half life is 23.03 minutes. How much of 1.4228 g sample would remain after 1.368 hours? 3. The decay of antimony-131 is first order with a half life is 23.03 minutes. How long (in minutes) would it take for a 0.8893...
11 Properties of Radioactivity Prelaboratory Questions Name Laboratory Section 1. The decay behavior of a radioactive substance obeys first order kinetics: In (N/N.) = -kt, where N is the amount of radioactive nuclei at time = t seconds, N, is the amount at t = 0 seconds, k is the first order rate constant, and t is the elapsed time. If the half-life of the radioactive nuclei is 10 minutes, calculate the amount that remains after 75 seconds. (Hint: at...
11. (5 pt) For a 1 mCi sample, what is the activity of 18F in Bq? 18F decays by positron emission with a half-life of 109 minutes. a. 3.7 x 104 Bq b. 3.7 x 107 Bq c. 3.7 x 1010 Bq d. 2.7 x 10-3 Bq e. 2.7 x 10-11 Bq
please show all formulas/work 5. The decay constant of a radioactive source is 0.300/minute. - How much time must elapse before the activity is reduced to… (a) 85%? (b) 25%? (c) 5%? B) The half-life of a radioactive source is 14.0 minutes. - How much time must elapse before the activity is reduced by… (a) 70%? (b) 45%? (c) 20%? C) Radon-222 has a physical half-life of 30.0 days. A 10.24 microgram piece of this source is placed in storage....
A sample of drinking water collected from a suburban Boston municipal water system in 2002 contained 0.55 pCi/L of radon. Assume that this level of radioactivity was due to the decay of 222_Rn (t_i/2 = 3.8 days). 1 picocurie (pCi) = 1 times 10^-12 Curies (a) What was the level of radioactivity of this nuclide in the sample? Number (b) How many disintegrations per hour would occur in 2.5 L of the water?
Consider a certain type of nucleus that has a rate constant of 2.56×10−2min−1.Calculate the time for the sample to decay to one-sixth of its initial value. a. 70 min b. 33.8 min c. 0.0512 min d. 54.1 min e. 2.56 min
Consider a certain type of nucleus that has a rate constant of 2.03 x 10–2 min–1. Calculate the time required for the sample to decay to one-fourth of its initial value.
After watching the lectures I am still having a hard time understanding these equations. 1. The half-life of tritium is 12.3 years. How long does it take for a 48.0g sample to be reduced to 2.0g? Answer using equation(s). (I know itll be around 50 years but unsure about the equation) 2. Write balanced equations for: bismuth-214 undergoes beta decay, plutonium-242 emits alpha radiation, selenium-81 undergoes beta decay, uranium-235 undergoes alpha decay, 11C emits a positron, O-15 undergoes electron capture...
The number of coliform bacteria is reduced from an initial concentration of 2 million per 100 mL to 400 per 100 mL in a long narrow chlorination tank under steady wastewater flow with a hydraulic detention time of 30 min and a chlorine concentration of 5.2 mg/L. Assuming, n = 1.3, first-order kinetics and ideal plug flow, calculate the reaction-rate constant. Using this rate constant, find the effluent concentration if the reactor is operated as a completely-mixed reactor. Hint: θ...
Calculate the specific activity for each sample using the
formula:
1 unit (specific activity) = 1000 x (A420– (1.75 x
A550) / (T x V x A600)
where:
A420= absorbance of the yellow ONP
A550= cell debris light scattering
T = reaction time in minutes
V = volume of culture assayed (ml)
A600= cell density
Sample
Calculation
Activity
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β galactosidase Activity (10 points) RESULS Ex. 1 1 a: Acoo |...