use the nuclear decay equation to find out how much a 7mg sample of iodine 128 remains after 116 minutes if the half life of this isotope is 25 minutes

216,032 results

1. chemistry

use the nuclear decay equation to find out how much a 7mg sample of iodine 128 remains after 116 minutes if the half life of this isotope is 25 minutes.
2. chemistry

a radioactive material is undergoing nuclear decay. After 40 minutes, 25% of the sample remains. What is the half-life of the sample
3. College Algebra

Use a calculator to help solve the problem. One isotope of holmium, 162Ho, has a half life of 22 minutes. The half-life of a second isotope, 164Ho, is 37 minutes. Starting with a sample containing equal amounts, find the ratio of the amounts of 162Ho to 164Ho after two hours...

2. An isotope of sodium has a half-life of 15 h. A sample of this isotope has a mass of 2 g. a. [2] Find the mass equation that remains after t hours. b. [1] Find the mass that remains after 5 hours, to the nearest hundredth. c. [2] How long, to the nearest hour, will the ...
5. Chemistry

I've figured out most of it. I'm not sure how to find the percentage ofd the isotope. Define the half life. The half-life of a radioisotope is found to be 4.55 minutes. If the decay follows first order kinetics, what percentage of isotope will remain after 2.00 hours if you ...
6. chemistry

a radioactive material is undergoin nuclear decay. After 40 minutes, 25% of the sample remains. What is the half life of the sample? Pls say the formula how to calculate it a)10 mins b) 20 mins c) 40 mins d)80 mins e) 160 mins
7. 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 10 3min looks like ...
8. college algebra

One isotope of holmium, 162Ho, has a half life of 22 minutes. The half-life of a second isotope, 164Ho, is 37 minutes. Starting with a sample containing equal amounts, find the ratio of the amounts of 162Ho to 164Ho after one hour. Rounded to three decimal
9. Chemistry

Gallium65, a radioactive isotope of gallium, decays by first order-kinetics. The half-life of this isotope is 15.2 min. How long would it take for 7/8 of a sample of this isotope to decay? 15.2 min 30.4 min 45.6 min 48.0 min I'm not sure how to do this. I initially tried by ...
10. Chemistry

The most abundant isotope of the element nobellum has a half-life of 58 minutes. After 174 minutes the sample has a mass of .300 mg. What was the orignal mass of the sample? A. 1.20 mg B. 4.80 mg C. .600mg D. 2.40 mg
11. Chemistry

How long will it take for a 18.0-g sample of iodine-131 to decay to leave a total of 2.25 g of the isotope? The half-life of iodine-131 is 8.07 days
12. Calculus

The rate of decay is proportional to the mass for radioactive material. For a certain radioactive isotope, this rate of decay is given by the differential equation dm/dt = -.022m, where m is the mass of the isotope in mg and t is the time in years. A. If m(0)=20, write a ...
13. Physical Science

Here are some half-lives for different isotopes of bismuth (Bi): Bi-211 — 2.1 minutes Bi-212 — 60.6 minutes Bi-213 — 45.7 minutes Bi-214 — 19.9 minutes If there are 200 grams of one isotope of bismuth, and after 60.6 minutes there are 100 grams of bismuth, what isotope...

Iodine-131 is a radioactive isotope. After 8.00 days, 50.2% of the sample remains. What is the half life of 131-I?
15. Chemistry

Iodine 131 is a radioactive isotope. After 4.00 days, 70.8% of a sample of 131I remains.What is the half life of 131I?

Which of the following statements about radioactive dating is true? a. Radioactive decay is the rate at which new atoms form. b. During radioactive decay, atoms break down, releasing particles or energy. c. The rate of decay of a radioactive element cannot be approximated. d. ...
17. Half-Lifes

How much of a 6gram sample of silver-105m would remain after 4 minutes? Half life=7.2 minutes
18. science

If the half-life of a 20.0g is known to be 24 minutes, how long will it take for only 5.0 grams of the sample to remain A.6 minutes B.24 minutes C.48 minutes D.96 minutes I NEED HELP!!!!
19. math

What is the figure that gives the half-life of the isotope in minutes to 4 significant figures? Exponential regression on a set of data, which gives the amount of atoms of a radioactive isotope remaining after a time X minutes, produced the following output. ExpReg y = a*b^x a...
20. 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
21. 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?
22. Chemistry

How to work out: The half-life of Indium-116 is 14 seconds. How long will it take for 32g of this isotope to decay to 1.og?
23. chemistry

the half-life of polonium-218 is 3.0 minutes. what percentage of the original sample remains after 4 half-lives?
24. s103

the isotope caesium -137, which has a half life of 30 years, is a product of nuclear power plants. How long will it take for the amount of this isotope in a sample of caesium to decay to one sixteenth of its original amount? - explain answer 1/16 = 1/2^x 2^x = 16 Solve for x.
25. Chemistry

Barium-122 has a half-life of 2 minutes. If 10.0 g of Ba-122 are produced in a nuclear reactor how much Ba-122 will remain 10 minutes after production ceases? Question 11 options: 2.50 g 1.25 g 0.625 g 0.313 g
26. chemistry

Fluorine-20 has a half-life of 11.0 s. If a sample initially contains 49.0 μg of this isotope, how much remains after 66.0 s ?
27. calculus

a radiotactive isotope lose 1/5 of its atoms in a sample decay after 14 years. find the half life.

The activity of a sample of Ba-137m has decreased by 75% from its initial activity after 5.10 minutes. What is the half-life of Ba-137m? What fraction of activity remains after 6.25 minutes? (A=Aoe (-kt); k = .693/t1/2)
29. modern physics

A radioisotope P has a half-life of 3 s. At t = 0, a given sample of this isotope contains 8000 atoms. Calculate (i) its decay constant, (ii) average life, (iii) the time t1 when 1000 atoms of the isotope P remain in the sample, and (iv) number of decays per second in the ...
30. physics

The half-life of the plutonium isotope is 24,360 years. If 10 grams of plotonium is released into the atmosphere by a nuclear accident, how many years will it take for 80% of the isotope to decay?
31. Calculus

My teacher wants me to use this formula for half life question C(t) = Ce^-kt but i used a different formula plz help. the question is: A radioactive isotope has a half life of 30 years. If we started off with 10 mg of this isotope 12 years ago: a) Find and expression for the ...
32. Half-life

After two hours, 1/16 of the initial amount of a radioactive isotope remains undecayed. What is the half-life of the isotope?
33. chemistry

the half time of a radioisotope is found to be 4.55 minutes. if the decay follow first order kinetics. what percentage of isotope will remain after 2.00 hours?

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 the radiation dosage...
35. chemistry

It takes 1 hour and 17 min. for a 1.000g sample of a certain isotope to decay to 0.121g. What is the half-life of this isotope? plssss helpp
36. Physics (Inside the atom)

A sample of radioactive isotope I is to be used for medical diagnosis of the kidneys. The isotope has a half-life of 8.0 days, and the sample is required to have an activity of 8 x 10^5 per second at the time it is given to the patient. Calculate the mass of the I-131 present ...
37. college chemistry

The half-life of 13252Te is 3.26 days. This isotope decays by beta emission to a highly unstable intermediate that decays rapidly to a stable product by beta emission. (a) What is the ultimate product obtained from Te-132? Write a balanced equation for this reaction. (b) ...
38. Chemistry

If a 40 gram sample of radioactive isotope was present at 4pm, but a 5 gram sample remained at 4:30 pm, what is the half-life in minutes?
39. science

Please help me with this question.... The isotope caesium-137, which has a half-life of 30 years, is a product of nuclear power plants. How long will it take for the amount of this isotope in a sample of caesium to decay to one-sixteenth of its original amount? k = 0.693/t1/2...
40. Science economic

Cesium 138 has a half life equal to 32.2 minutes. how long will it take for 2/4 of this sample to decay
41. Algebra

A radioactive kind of nitrogen has a half life of 10 minutes. If you start with 64 grams of the substance, how much will be left after 20 minutes?
42. chemistry

an original sample of K-40 has a mass of 25.00 grams. After 3.9x 10 to the ninth years, 3.125 grams of the original sample remains unchanged. What is the half-life ok K-40 in minutes? Is it 6.8328 x 10 to the 14th

Nuclear medicine technologists use the Iodine isotope I-131, with a half-life of 8 days,to check thyroid function of patients. After ingesting a tablet containing the iodine, the isotopes collect in a patient's thyroid, and a special camera is used to view its function. ...
44. 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 iodine - 131 remains in...
45. Chemistry

How much of a 50.0 grams sample of Uranium-238 would remain after 26 minutes IF the half-live is 13.0 minutes?? This question has stummed me and I can't do it, ugh.
46. 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 the radiation dosage...
47. isd muscat

after two hours 1/16th of the radioactive isotope remains undecayed.half life of the isotope is
48. calculus

Question: "Plutonium isotope Pu-239 has a half-life of 24,100 years. Suppose that 10 grams of Pu-239 was released in the Chernobyl nuclear accident. How long will it take for the 10 grams to decay to 1 gram?" I know that I am suppose to use y= ye^kt , to get the equation and ...
49. math-natural log

Nuclear medicine technologists use the Iodine isotope I-131, with a half-life of 8 days,to check thyroid function of patients. After ingesting a tablet containing the iodine, the isotopes collect in a patient's thyroid, and a special camera is used to view its function. ...
50. physics

in an initial mass of 40g, how much mass Remaining of the Isotope Approximately how much mass remains after 8.0 hours? After 21 hours, and what is the half life of the isotope
51. Chemistry

Will you check this answer for me? the half-life of strontium-87 is 2.8hr. What percentage of this isotope will remain after 8 hours and 24 minutes? ?? 34%
52. calculus

The rate at which an amount of a radioactive substance decays is modeled by the differential equation dA/dt = kA, where A is the mass in grams, t is the time in years, and k is a constant. Answer the following. a) If a 100-gram sample of the radioactive substance decays to 95 ...
53. chemistry

isotope A require 12h for its decay rate to fall to 1/64 of its intial value . isotope B has half-life = 1.5 half life of A how long does it take for decay rate of B fall to 1/32 of its initial value ?
54. Chemistry

After 1.78 years, 1.990 g of a radioisotope remains from a sample that had an original mass of 2.000 g. Calculate the half-life of the isotope.
55. Math

Natalie performs a chemistry experiment where she records the temperature of an ongoing reaction. The solution is 93.5º C after 3 minutes; 90º C after 5 minutes, 84.8 C after 9 minutes; 70.2º C after 18 minute; 54.4º C after 30 minutes; 42.5ºC after 37 minutes; and 24.9...
56. chemistry

A radioactive isotope of radium (Ra-226) has a half-live of 1620 years. How much of this isotope remains after three (3) half-lives? A. 1/2 B. 1/4 C. 1/8 D. None would this be C? please explain, thank you!

A radioactive isotope of radium (Ra-226) has a half-live of 1620 years. How much of this isotope remains after three (3) half-lives? A. 1/2 B. 1/4 C. 1/8*** D. None
58. chemistry

A radioactive sample contains 2.45 g of an isotope with a half-life of 3.8 days. How much of the isotope in grams will remain after 11.4 days?

There are 3.29g of iodine -126 remaining in a smple originally containing 26.3 g of Iodine - 126 the half life of Iodine - 126 is 13 days. How old is the sample? At study hall test is after lunch and cant figure out htese 2 on my review packet
60. Chemistry

Write a nuclear equation for the following: Iodine 131 undergoes beta decay two times Plutonium 239 is an alpha emitter Th 234 undergoes beta decay once and then alpha decay How do I go about writing nuclear equations?
61. Physcis 30

Q1) If there are 100 radioactive atoms with a half-life of 30 seconds, how many radioactive atoms will remain after one half-life (30 seconds)? How many will remain after two half-lives (60 seconds)? Three half-lives? So basically, after 30 seconds it will be 50.After 60 sec. ...
62. math

The radioactive isotope sodium-24 is used as a tracer to measure the rate of flow in an artery or vein. The half life of sodium-24 is 14.9 hours.Suppose that a hospital buys a sample of sodium-24 a. how much of the sample will remain AFTER 48 Hours? b. How long will it be ...
63. half-life

the half life of isotope X is 2.0 years how many years would it take for 4.0 mg sample of X to decay and have .50 mg of it remain?
64. chemistry

use logic and simple math to determine how long it will take for a sample of potassium- 42 to decay from 8mg to 0.25mg if the half-life of this radioactive isotope is 124 hours
65. Physics

So we did this lab about how we are to measure the half life of the beta decay of indium 116 (the indium 116 is captured by indium 115 and undergoes beta decay to become tin 116. Since the Indium 116 I reused I understand that every time we use it, the indium 116 becomes a ...
66. chem

The half-life of the Nobelium isotope No^257 is about 23 seconds. 644 seconds (or 28 half-life periods) after the isotope was released there were 20 grams remaining. The number of grans of No^257 after h half life periods is M= 20 * (1/2)^h where h = 0 corresponds to 644 ...
67. chemistry

Examine the information. Isotope B has a half-life of 3 days. A scientist measures out 100 grams of this substance. After 6 days has passed, the scientist reexamines the sample. How much of Isotope B will remain in the sample? 100 grams 63 grams 94 grams 25 grams
68. Math - D.E.Q.

The half-life of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to one-half of its original amount. i) The half-life of Carbon 14 (C-14) is 5230 years. Determine the decay-rate parameter  for C − 14.
69. Math - Algebra

Need help understanding this problem. Looks like an exponential growth/decay. Magnesium-27 has a half life of 9.45 minutes and can be described by using the equation “y=ae^-kt . What is the decay constant (k) for Magnesium-27? How many mg of Magnesium-27 will remain after 1....
70. chemistry 1405

how to write a nuclear equation for the nuclear decay of Ra-226 to an isotope of radon-222
71. math

The half life of iodine - 131 is 8 days. How long will it take for 7/8 of the sample to decay?
72. Math

Natalie performs a chemistry experiment where she records the temperature of an ongoing reaction. The solution is 93.5º C after 3 minutes; 90º C after 5 minutes, 84.8 C after 9 minutes; 70.2º C after 18 minute; 54.4º C after 30 minutes; 42.5ºC after 37 minutes; and 24.9...
73. algebra 1

Natalie performs a chemistry experiment where she records the temperature of an ongoing reaction. The solution is 93.5º C after 3 minutes; 90º C after 5 minutes, 84.8 C after 9 minutes; 70.2º C after 18 minute; 54.4º C after 30 minutes; 42.5ºC after 37 minutes; and 24.9...
74. Algebra

A defective nuclear reactor is leaking radioactive iodine-131. The rate of decay of iodine-131is given by the function defined by A(t)=A_0 e^(-0.087t), where t is time in days. How long will it take any quantity of iodine-131 to decay to 25% of its initial amount?
75. 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?
76. chemistry

What is the half-life of an isotope if it decays to 12.5% of its radioactivity in 18 minutes?
77. Chem

The decay constant for a radioactive isotope is 7.82 x 10-6 /y. What is the half-life of this isotope in years?
78. half life

If the radiological half life of a material is 31 minutes, and you have 77 grams now, how much did you have 55 minutes ago?
79. Math

the half-life of iodine-131 is 8 days. how much iodine-131 will be left After 35 grams sample after 32 days?
80. 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 atomic masses. thanks ...
81. Science

Nobelium -259 has a half life of 58 min? How much remains of 1kg sample after 1 day? Use the formula. A= Aö (1/2) t/h
82. Exponential Decay

the half-life of carbon-11 is 20 minutes. How long will it btake for 600g of carbon-11 to decay to 30g?
83. 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?
84. math30

The mass of a radioactive sample is represented in the graph below. The initial mass of 32 mg decays to 8 mg after 21 hours. 1)What is the half-life of the radioactive sample, in minutes? 2)Solve each equation. a. 4 8x-1 = 8 b. 3^(2x-5) = 1/27x
85. algebra 1

*I have asked countless people to help me with this story problem and nobody seems to know how to do it! Please help! Natalie performs a chemistry experiment where she records the temperature of an ongoing reaction. The solution is 93.5º C after 3 minutes; 90º C after 5 ...
86. algebra 1

Natalie performs a chemistry experiment where she records the tenperture of an ongoing reaction.The solution is 93.5 C after 3 minutes;90 C after 5 minutes,84.8 C after 9 minutes; 70.2 C after 18 minute; 54.4 C after 30 minutes;42.5 C after 37 minutes; and 24.9 C after 48 ...
87. Physics

A certian radioactive isotope has a half-life of 1 hour. If you start with 1 gram of the material at noon, how much of the original isotope will the sample contain at 3 pm? At 6 pm? At 10 pm?
88. Science chemistry

It takes 1 hour and 17 min. for a 1.000gsample of a certain isotope to decay to 0.121g. What is the half-life of this isotope? plssss helpp
89. math

I asked the following the other day and received the following answer: Posted by Matthew on Sunday, March 17, 2013 at 11:03pm. A quantity of oxygen gas had 16.32 g of the radioactive isotope oxygen-19 in it. When measured exactly 10 minutes later, the amount of oxygen-19 was 0...
90. DrBob222

On Monday you helped me to understand and answer the one question, but I am not too sure if they want all the calculations that you answered... regretably, I am still a bit lost with these! Below is the question as it is printed: The isotope caesium-137, which has a half-life ...
91. 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 information, I could...
92. 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 the short half-life ...
93. 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 isotope. What is the half-...
94. chemistry

isotope chromium -51 has a half life of 28 days. If the original sample had a mass of 28.0 grams, what mass of chromium -51 sample remains after 84 days?
95. Chemistry

As a sample of the radioactive isotope 131 I decays, its half-life a)decreases b)increases c)remains the same
96. SCIENCE

We did a radioactive decay and half life lab with m&ms and I do not understand these conclusion questions: 1. how many half lives would it take for 500 nuclei to decay to 6.25% of the original number of nuclei? My ans: 3125?- do not think that's right! 2. Is there any way to ...
97. Math

_The_Natural_Base_e_ An accident in 1986 at the Chernobyl nuculear plant in the Ukraine released a large amount of plutonium (Pu-239)into the atmosphere. The half-life of Pu-239 is about 24,110 years. Find the decay constant. Use the function N (t) = N 0 e -kt to find what ...
98. CHEM

Pu-239 has a half-life of 24110 y. If 1.00 kg of this isotope is present in the used fuel rods of a nuclear power plant approximately how long will it take for this amount of Pu-239 to decay until there is less than 1 mg left ? Please help. I do not know how to do this question.
99. chemistry

H2 + I2 -> 2Hl 1.2 mol of hydrogen gas reacts with 1.0 mol of iodine vapour, after 5 minutes 0.6 mol of iodine remained. A) calculate the number of moles of hydrogen that have not reacted after 5 minutes. B) calculate the number of moles of hydrogen iodide that have been ...
100. chem

Po-218 is an alpha emitter with a half-life of 3.0 minutes. If a sample contains 69 mg of Po-218, how many alpha emissions would occur in 6.0 minutes? the answer has to be _________a emmisions (which I have no idea what it means) and I use a chart thing with amount, #H-L, and ...