Gold-198 with a half life of 2.6 days is used to diagnose and treat liver disease. Write a half life decay equation that relates the mass of au-198 remaining to time in days. What percentage of a sample of Au-198

27,174 results
  1. English

    Which accurately describes the experience of gold seeker traveling to the Klondike? a. most gold seekers travel the whole distance by water b. about half of the gold seekers complete the journey to the Klondike*** c. all gold seeker were aided by the

  2. Gen Chem

    Neptunium-239 has a half-life of 2.35 days. How many days must elapse for a sample of 239-Np to decay to 1.00% of its original quantity? I got: close to 15 days. Is this right? I figured that about 1% of the original quantity would be roughly 6.5 Half

  3. Chemistry

    Earth's oceans have an average depth of 3800 m, a total area of 3.63 108 km2, and an average concentration of dissolved gold of 5.8 10-9 g/L. (a) How many grams of gold are in the oceans? (b) How many cubic meters of gold are in the oceans? Assuming the

  4. chemistry

    the half-life of radon-222 is 3.823 days. what was the original mass if 0.050g remains after 7.646 days?

  5. half-life of radioisotope

    A radioisotope has a half-life of 4 days. How much of a 20-gram sample of this radioisotope remains at the end of each time period? 1) 4 days 2) 8 days

  6. chemistry

    The half life of phosphorus -32 is 14.3 days. What percentage of an original samples radioactivity remains after 57.2 days?

  7. Physics

    Gold-198 with a half life of 2.6 days is used to diagnose and treat liver disease. Write a half life decay equation that relates the mass of au-198 remaining to time in days. What percentage of a sample of Au-198 would reamin after 1 day, 1 week? Given the

  8. calc

    The half-life of polonium is 139 days, but your sample will not be useful to you after 95 % of the radioactive nuclei present on the day the sample arrives has disintegrated. For about how many days after the sample arrives will you be able to use the

  9. chemistry--please check

    1. For the 1st order reaction whose rate law constant, k, is 1.5x10-3s-1, t½ is a. 7.7 minutes *** b. 462 minutes c. 6.5 minutes d. 4.5 minutes 2. If the half-life of a 1st order reaction is 137 minutes, k= a. 8.43x10-5s-1 b. 11,900 s-1 c. 5.06x10-3s-1

  10. Chemistry

    The half life of an element X is 5 days. If we have 10g of X intially, what is the mass of X for 5 days

  11. Physical Science- Help Please!

    Suppose that you are given a 100 gram sample of a radioactive substance with a half-life of 32 days. How many grams will be left after 192 days?

  12. UIW

    Neptunium-239 has a half-life of 2.35 days. How many days must elapse for a sample of 239Np to decay to 0.100% of its original quantity

  13. Chemistry (Dr.Bob222)

    The half-life of P-32 is 14 days. How long after a sample is delivered can a laboratory wait to use a sample in an experiment if they need at least 10 percent of the original radioactivity? I need help on how to set up this problem. What is the general

  14. chemistry

    There are 5g of 131I left after 40.35 days. How many grams were in the original sample if its half-life is 8.07 days? What is the half life of a radioisotope if you started with 1 gram and 0.250 grams is left after 6 days? im not looking for a free answer,

  15. chemistry

    If there are 80 milligrams of a radioactive element decays to 10 milligrams in 30 minutes then what is the elements half life in minutes? Ok i narrowed it down to either 10 or 30...but im rly confused so if u could help it wuld be grea 80 40 1 min 20 2 min

  16. science

    The iodine-131 nuclide has a half-life of 8.0 days. If you originally have a 257 g sample, after 48 days how much will you have?

  17. physical science

    A sample of phosphorus-32 has a half-life of 14.28 days. If 55 g of this radioisotope remain unchanged after approximately 57 days, what was the mass of the original sample? help please, im confused.

  18. half-life

    1. The half-life of a first-order reaction is 9.89 minutes. How many minutes will have elapsed after 27 half-lives? My answer is 267.03. 2. The half-life of a second-order reaction is 2.508 days. How many days will have elapsed after 8 half-lives? My

  19. CALC -- integrals!

    Iodine-131 is used to treat hypo-thyroidism since it is preferentially absorbed by the thyroid and typically involves a total radiation dosage of 10,000,000 millirem. Iodine-131 has a half-life of eight days. 1. Set up the appropriate integral to represent

  20. physics

    If half life of iodine 131 is 8 days, how much from 32g remain after 40 days (5 half lives).

  21. 12th grade Math - word problems

    #1.) The population of bacteria after t hours is given by P(t) = 500/(1+83.33e^-0.162t) a.) What is the initial population? b.) When will the amount of bacteria in the population be 12? #2.) Which investment yields the greater amount after 4 years? a.)

  22. science

    A Geiger counter is used to measure the activity of a sample of iodine-131. Based on the data, what is the half-life of iodine-131? A. 16 days B. 8 days C. 4 days D. 12 days

  23. science

    a radioisotope, Iodine-131, has a half life of 8.1 days. explain what this means. draw a particle diagram for a sample 12 particles of I-131 initially after 8.1 days and after16.2 days.

  24. health

    All of the following are true of alcoholism EXCEPT: - those who abuse alcohol are twice as likely to die of cancer - Much of the research suggests that genetics plays very little role in the disease - Males are three times more likely to abuse alcohol than

  25. Chemistry

    What is used to tell different isotopes of a particular element apart? A. the mass number B. the atomic number C. the number of protons D. the number of electrons A is the answer. After how many half-lives are there equal amounts of parent and daughter

  26. Chemistry

    The half life of radon 222 is 3.82 days. If the initial mass of a sample of radon 222 is 198.72 grams, how much will remain after 19.25 days?

  27. Exponential Growth and Decay

    Doctors use iodine-131 to treat some forms of cancer. The half-life of iodine-131 is 8 days. A patient receives a treatment of 12 millicuries. A millicurie is a unit of radioactivity. How much iodine-131 remains in the patient 16 days later?

  28. Math

    1. Iodine-131 is used to find leaks in water pipes it has a half life of 8.14 days. If 36 days have passed and there is now 2.34g left. What is the initial amount? 2. Sr-85 is used in bone scans and has a half life of 64.9 days. If there is 23 percent of

  29. math

    You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. You purify a sample of 2 grams. One of your colleagues steals half of it, and eight days later you find that 0.1 gram of the

  30. Chemistry

    The iodine-131 nuclide has a half-life of 8 days. If you originally have 625-g sample, how many grams will you have after 2 months(approximately 64 days)?

  31. Health

    Can anybody give me the name of a liver disease that may be caused by smoking? It has 9 letters, and the fifth one is "h". Search 'liver disease' and smoking on google and you'll find it. I'm sorry, I couldn't find it. well, just searching 'liver disease'

  32. hca 240

    I’m sending little Jimmy over for a stat spinal tap. He has had a fever for a couple of days, which increased to 102 degrees today. Since yesterday he’s been complaining of a headache and stiff neck. His mother said last week he had gone swimming in

  33. math

    Iodine-131 is a radioactive isotope used in the treatment of thyroid conditions. It has a half-life of 8 days. Half-life is the amount of time it takes for half of the substance to decay (or disappear). If a patient is given 20 mg of iodine-131, how much

  34. Chemistry

    Which radioactive sample would contain the greatest remaining mass of the radioactive isotope after 10 years? A. 2.0 grams of 198 Au B. 2.0 grams of 42 K C. 4.0 grams of 32 P D. 4.0 grams of 60 Co By the way the numbers next to the elements are their

  35. chemistry

    How do you find the half-life of an element? Please explain and show me how to do this. I know the answer is 14.3 days, but I don't know how to work it. thank you! the problem is: After 42 days, a 2.0-g sample of phosphous-32 contains only 0.25g of

  36. Math with science

    Radioactive iodine treatment is so successful at treating hyperthyroidism that it has virtually replaced thyroid surgery. To the nearest full day, determine how long it will take for 400 millicuries of I-131, which has a half-life of 8 days, to decay to

  37. algebra

    Andrew measures they amount of a very unstable substance to be 100 moles. the half life of this substance is 3 days(after 3 days, half is gone). write an exponential function that models this situation where Y is the amount of substance and X is time in

  38. Chemistry. Half Life Problem. Help Plz

    If the half-life of iodine-131 is 8 day, how much would remain undecayed after 8 day if we started with 38 grams? How much at 16 days? 24 days? 32 days?

  39. Advanced Math Help!

    suppose m(0) milligrams of a drug are put in the blood of an injection. The amount of drug t hours after the injection is given by m(t)=m(o)e^-kt, for t (=>) 0, where k is the rate constant, which is related to the half life. we also treat oral

  40. Pre-Calc

    A radioactive isotope has a half life of 8.1 days. If the sample starts with 25 grams, how much will there be after 90 days?

  41. chem

    The half-life of is 30.0 days. What fraction of a sample of this isotope will remain after 16.2 days?

  42. Algebra

    A contagious disease is infecting residents of a town of 7,300 residents. The number of residents infected t days after the disease has begun is given by the function f(t)=(7300)/1+500e^-0.5 t How many residents are infected with the disease after 6 days?

  43. Chemistry

    A radioactive element has a half-life of 6.41 days. What percent of the original sample will be left after 15.0 days?

  44. earth science

    if carbon 14 has a half life of 24 days how much would be left of 220 gram sample after 168 days

  45. Algebra 2

    A particular radioactive element has a half life of 10.0 days. How much is left after 30.0 days if the sample started with 345g?

  46. Chemistry

    Uranium-238 has half life of 4.51 * 10^9 years Uranium-234 has half life of 2.48 * 10^5 years Thorium-230 has half life of 8.0 * 10^4 years Radium-226 has half life of 1.62 * 10^3 years Lead-210 has half life of 20.4 years. The rate constant for the decay

  47. Math

    You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physic. You purify a sample of 2 grams.One of you colleges steals half of it, and 3 days later you find that 0.1 grams of the radioactive

  48. Life o

    Describe the life style of Hypertension disease and 12 explanation. Provid 10 ways in which you critically discuss how life style/behaviour disease impact on the teenager?

  49. Chemistry

    Ba-140 has a half life of 13.0 days. What fraction of a sample of Ba-140 will remain after 39 days? A. 1/8th B. 1/16th C. 1/2th D. 1/4th

  50. chemistry

    A radioactive sample contains 2.45g of an isotope wiht a half life of 3.8 days. How much of the isotope in grams remains after 11.4 days? please explain

  51. Chemistry

    The half-life of 131I is 8.021 days. What fraction of a sample of 131I remains after 24.063 days? 1/2 1/4 1/8 1/16 Please help. Thank you

  52. math

    If, initially, there is 20 mg of gold-198 (198Au) (half-life = 2.696 days), how many days does it take for less than 1 mg to remain?

  53. physics

    If the physical half-life of sulfur-35 is 87.1 days, and the biologic half-life in the testicle is 632 days, what is its effective half-life in this organ? I know i have to find the time and then the half-life. But im having trouble finding the time

  54. Chemistry

    Tc-99 is a radioactive isotope that decays by beta emission and is used by radiologists in the diagnosis of liver disease. Its decay behavior is shown by the activity-time table. What is its half-life?

  55. Science Half Lives

    I am confused about how to claculate half lives. Can you explain. ( How much of a 400 gm sample od gold is left after 10.8 days if the half life is 2.7)

  56. chemistry

    a 15g sample of gold-198 decays in 3g in 6 days. how much will be left after 8 days?

  57. calculus -- PLEASE HELP!

    Iodine-131 is used to treat hypo-thyroidism since it is preferentially absorbed by the thyroid and typically involves a total radiation dosage of 10,000,000 millirem. Iodine-131 has a half-life of eight days. 1. Set up the appropriate integral to represent

  58. history

    i need to invent a terrible disease myself that has been detected in another part of the world .. the people are unhappy because the government are not helping them to treat the disease..please help me find a terrible disease but it has to be

  59. chemistry

    Some radioactive nuclides have very short half-lives, for example, I-31 has a half-life of approximately 8 days. Pu-234, by comparison has a half-life of 24,000 years. Explain why both of these examples are dangerous, even though their half-lives are very

  60. Math

    Please show me how to solve: Doctors can use radioactive iodine to treat some forms of cancer. The half-life of iodine - 131 is 8 days. A patient receives a treatment of 12 millicuries of iodine - 131. (A mullicurie is a unit of radioactivity.) How much

  61. chemistry

    The disintegration of a radioisotope, such as I-131 to Xe-131, is another example of a first-order reaction. It has a half-life of 8.0 days. I-131 -> Xe-131 + e If you start with 1.40 g I-131, how many grams of I-131 will be left after the following days?

  62. math

    The half life of the radio active substance is the time require the half the substance to decay. the mount A ( in grams) of 100 gram sample of a radio active substance remaining after t half lives by A equals to 100 (0.5) t. suppose the substance has a

  63. college

    . S-35 (t1/2 = 87.4 d) is used in cancer research. The biological half-life in the human body is 90 days. What is the effective half-life of S-35?

  64. college chem

    S-35 (t1/2 = 87.4 d) is used in cancer research. The biological half-life in the human body is 90 days. What is the effective half-life of S-35?

  65. hca240

    Case Study 2: Name Jimmy Schwimmer Patient # 45645645 DOB: 11/03/2002 Physician Dr. Raychee Date: 04/21/20XX INTER-OFFICE REFERRAL FORM Melissa Neidermayer, M.D. Doctors-R-Us – North Campus 1515 N. Medical Plaza #203 Anytown, Anywhere 12345 Dear Melissa,

  66. Algebra

    Andrew measures the amount of a very unstable substance to be 100 moles. The half-life of this substance is 3 days (after 3 days, half is gone). Write an exponential function that models this situation where y is the amount of substance and x is time in

  67. CALCULUS PLEASE HELP!!

    suppose m(0) milligrams of a drug are put in the blood of an injection. The amount of drug t hours after the injection is given by m(t)=m(o)e^-kt, for t (=>) 0, where k is the rate constant, which is related to the half life. we also treat oral

  68. CALCULUS PLEASE HELP

    suppose m(0) milligrams of a drug are put in the blood of an injection. The amount of drug t hours after the injection is given by m(t)=m(o)e^-kt, for t (=>) 0, where k is the rate constant, which is related to the half life. we also treat oral

  69. physics

    if you have an element that starts out at 40g and has a half-life of 10 days, you keep it for 30 days- how much doe you end up with? .

  70. CHEM

    An isotope has a half life of 56 days. It now has 10,000DPM/ml. What will its activity be 100 days from now?

  71. chemistry

    Ba-140 has a half life of 13.0 days. What fraction of a sample will remain after 39 days?

  72. algebra

    A contagious disease is infecting residents of a town of 7,300 residents. The number of residents infected t days after the disease has begun is given by the function f(t)= 7300/1+500e-0.5t How many residents are infected with the disease after 6 days?

  73. Chemistry

    A particular radioactive element has a half life of 10.0 days. How much is left after 30.0 days if the sample started with 345g?

  74. ALGEBRA

    You have 480 grams of a radioactive kind of tin. If its half-life is 10 days, how much will be left after 30 days?

  75. earth science

    if carbon 14 has a half life of 24 days how much would be left of 220 gram sample after 168 days

  76. Algebra

    The half-life of radon-222 is 3.8 days. How much of a 300 gram sample is left after 14.8 days?

  77. earth science

    if carbon 14 has a half life of 24 days how much would be left of 220 gram sample after 168 days

  78. Science

    The half-life of randon-222 is 8 days. What was the original mass if 6 grams remains after 24 days?

  79. Math

    The half-life of radon-222 is 3.8 days. How much of a 300 gram sample is left after 14.8 days?

  80. Science

    How we know that we have a liver disease?

  81. physics

    The half-life of Th(227) is 18.72 days. It decays by alfa emission to Ra(223), an alfa emitter whose half-life is 11.43 days. A particular sample contains 10^6 [10E(+6)] atoms of Th(227) and no Ra(223) at time t=0. a) How many atoms of each type will be in

  82. algebra

    the isotope has a very short life of 13 half-life days. estimate the percentage of the original amount of the isotope released by the explosion that remains 3 days after the explosion?

  83. Chemistry

    A radioactive sample contains 3.25 1018 atoms of a nuclide that decays at a rate of 3.4 1013 disintegrations per 26 min. (a) What percentage of the nuclide will have decayed after 159 d? % (b) How many atoms of the nuclide will remain in the sample? atoms

  84. Energy

    If the half life of Ir - 131 is 42 days, how much would be remaining after 168 days?

  85. Math

    This year my teacher read us the book The Phantom Tollbooth, and since then I've been having strange dreams about drving in usuaual places and paying tolls unusual characters.Last night I dreamed about highway in the clouds near the mythical Mt. Olympus.

  86. chemistry

    Iodine-131 has a half-life of 8 days. How many grams of a 12 g sample will remain at the end of 40 days? how do i solve this? i thought it was 12^40=1.5 but that's wrong...

  87. mym

    what are the factors that affect the rate of enzyme-catalyzed reactions in different liver parts ? For example, why does the reaction occur faster in lamb liver than chicken liver ?

  88. algebra

    Consider that the half-life of Polonium-210 is 140 days.What approximate daily percentage of decay does Polonium-210 demonstrate?% (Round to two decimals.)(Hint: use the Rule of 70 backwards by dividing by the half-life period instead of the rate.) What

  89. Physics 30

    The activity of a sample of a radioactive isotope is 1800Bq. If this isotope has a half-life of 16 days, what is the activity after 16 days?, 24 days?, and 60 days?

  90. math

    iodine 131 has a half life of 8 days. If 5 mg are stored for a week, how much is left? How many days does it take before only 1 mg remains? An explanation for each step would be nice please. I want to learn how to do these problems for my upcoming exam.

  91. Health

    I have a female red eared slider that has swollen eyes. I found out that it has a disease. I do not know where to get the antibiotics to help treat this disease and care for my turtle. If you know of any places or things I can do to help my turtle, then

  92. chemistry

    The half life of gold-197 is 10.6. What fraction of a sample remains after 21.2 years?

  93. Science

    Radium has a half-life of 1620 years and decays into radon, which has a half-life of 3.82 days. A 10-gm source of radium is sealed, and the radon produced is pumped off every 24 hours. How many mill curies of radon are pumped off each time?

  94. Chemistry

    2. The half-life of a radioactive element is important when considering its application in medicine. For example, iodine-131 is often used in the imaging of the thyroid. The reason is that iodine is readily absorbed by the thyroid gland. Another reason is

  95. Chemistry

    If a 300g sample of a substance has a half-life of 5 days, how much of the substance will decay after 22 days? A)293.4 g B)290.6 g C)285.8 g D)299.9 g

  96. chemistry

    The half-life of I-131 is 8.00 days. If a medical treatment involves a dose of 400. mg of I-131, how much of the isotope remains after 48 days? 3.125 mg 6.25 mg 12.5 mg 25 mg

  97. calculus

    The half-life of Radium-223 is 11.43 days. If a sample has a mass of 900 mg, find the mass (in mg) that remains after 5 days

  98. calculus

    The half-life of Radium-223 is 11.43 days. If a sample has a mass of 400 mg, find the mass (in mg) that remains after 6 days

  99. chemistry

    the half life radium-222 is 4 days. if a sample of radon-222 undergoes decay for 12 days, how much of the original parent isotope will be left?

  100. Math/Calculus

    After 5 days, a particular radioactive substance decays to 37% of its original amount. Find the half life of this substance. Is this right? Th= ln 2/ln(1/.37) x 5 days

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