Given the formula A=A0e^(kt) Where A0 is the original mass, and A is material present at t The half life of Pu239 is 24100 years, calculate how long it takes for Pu239 to decay to 70% of its original mass
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Math
Given the formula A=A0e^(kt) Where A0 is the original mass, and A is material present at t The half life of Pu239 is 24100 years, calculate how long it takes for Pu239 to decay to 70% of its original mass. 
science
Please help me with this question.... The isotope caesium137, which has a halflife 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 onesixteenth of its original amount? k = 0.693/t1/2... 
pre calculus
The age of a document is in dispute, so archaeologists test for carbon14. Due to radioactive decay, the amount A of carbon 14 present compared to the initial amount A0 after t years is given by the formula A(t) = A0e^0.000124t . If 72% of the original amount of carbon 14 ... 
Math  D.E.Q.
The halflife of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to onehalf of its original amount. i) The halflife of Carbon 14 (C14) is 5230 years. Determine the decayrate parameter for C − 14. 
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 ... 
Math
A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay constant. (a) ... 
Math
A radioactive substance decays according to the formula Q(t) = Q0e−kt where Q(t) denotes the amount of the substance present at time t (measured in years), Q0 denotes the amount of the substance present initially, and k (a positive constant) is the decay constant. (a) ... 
Physics HELP HELP
(for some reason I keep getting this wrong. I put 90 for c, 5.6 for h and 22 for M(x), Then I took the natural log of both sides, but I keep getting it wrong) The mass of a radioactive element at time x is given by the equation below, where c is the original mass and h is the ... 
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 ... 
algebra
A radioactive substance decays according to the formula A=A0e^kt where A0 is the initial amount of substance (in grams) A is the amount of substance(in grams) after t years k is a constant The halflife of the substance is 10 years.If we begin with 20g of the substance,how ... 
Math
A radioactive material has a half life of 500 years. A) Given 20 grams of this material, how much will remain after 1,000 years? B) Given 100 grams of this material, how much will remain after 750 years? Thank you to whom ever can help me :) 
Physics check
A certain radioactive isotope has a halflife of one hour. At noon, 100g of the material is present. How much of the original isotope will be present at 3:00 p.m.1/8 6:00 p.m.1/16 10:00 p.m.1/32 Are these correct? 
chemistry
The isotype 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 isotype in a sample of caesium to decay to onesixteenth of its original amount? first half life 1/2 second 1/4 third 1/8 fourth 1/16... 
Science
A material has 32 atoms in all; 24 decayed and the rest undecayed. If the halflife of the radioactive material is 1000 years, what is the age of the material? a. 1000 years b. 2000 years c. 3000 years d. 4000 years 
Calculus
Radius decays at a rate of that is proportional to its mass, and has a halflife of 1590 years. If 20 g of radium is present initially, how long will it take for 90% of this mass to decay? 
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 100gram sample of the radioactive substance decays to 95 ... 
math
How long will it take a given quantity of carbon14 to lose 99.9% of its radioactivity if the half life is 5730 years? The formula I have been given is Q=ae^rt This is using log and ln functions. 
Chem
If compound X has a firstorder halflife of 24 seconds, how long would you have to wait for only 33% of the original material to be left? Explain why not knowing original Molarity of X does not effect this problem. 
Physics (Inside the atom)
A sample of radioactive isotope I is to be used for medical diagnosis of the kidneys. The isotope has a halflife 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 I131 present ... 
Calculus
A certain radioactive material decays exponetially. The percent, P, of the material left after t years is given by P(t)= 100(1.2)^t a)Determine the half life of the substance 
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 halflife of the isotope. 
Chemistry
Uranium238 has half life of 4.51 * 10^9 years Uranium234 has half life of 2.48 * 10^5 years Thorium230 has half life of 8.0 * 10^4 years Radium226 has half life of 1.62 * 10^3 years Lead210 has half life of 20.4 years. The rate constant for the decay of unstable nuclide X... 
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 ... 
chem
Can someone please help me with the following questions? 1:Suppose you were given an ancient wooden box. If you analyze the box for carbon14 activity and find that it is 50% of that of a new piece of wood of the same size, how old is the wood in the box? 2:How old is an ... 
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.) $900 at 9% interest ... 
College Algebra
The halflife of a radioactive material is about 34.6 years. How much of a 1gram sample of the material is left after 30 years? 
chemistry
If compound x has a firstorder halflife of 24 seconds, how long would you have to wait for only 33% of the original material to be left? 
nuclear chem
i need help solving this. Can you guys show me how it's done. Radium226 decays by alpha emission to radon222, a noble gas.What volume of pure Radon 222 at 23oC and 785mmHg could be obtained from 543.0 mg of radium bromide,RaBr2 in a period of 20.2 years.The halflife of ... 
Chemistry please help!
A Cesium 137 sample has a measured radioactivity of 50 microcuries.Cesium 137 has a halflife of 30 years. How long will it take this sample to be reduced to a residual radioactivity of 6.25 microcuries? Is there a formula to calculate half life? 
Chemistry
It took 109.8 years for a 300.0 mg sample of an unknown radioactive material to completely disintegrate. Calculate the mass of the element (in grams/mole) assuming that the disintegrations per second are constant over the lifetime of the sample, and the sample is labeled 100.... 
precalculus
The function A=A0e^(0.0099x) models the amount in pounds of a particular radioactive material stored in a concrete vault, where x is the number of years since the material was put into the vault. If 600 pounds of the material are initially put into the vault, how many pounds ... 
Algebra 1
The function A = A0e0.01386x models the amount in pounds of a particular radioactive material stored in a concrete vault, where x is the number of years since the material was put into the vault. If 500 pounds of the material are initially put into the vault, how many pounds ... 
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 ... 
Math/Radioactive Dating
How would I calculate the age of a rock only given the amount of each in grams and halflife? 40K decays to 40Ar. Half life of 40K is 1.25 billion years. 40K = 20 grams 40Ar= 5 grams I think the formula is Final Amount of 40K = Initial Amount of 40K * (1/2)^(time/halflife) If... 
Calculus
If 40 milligrams of strontium90 radioactively decays to 12 milligrams in 30 years, find its halflife (the number of years it takes until half of it remains). Use the formula A = p ⋅ e−kt, where p is the amount and A the (smaller) final amount. 
math
An artifact was found and tested for its carbon14 content. If 76% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? (Carbon14 has a halflife of 5,730 years.) 
math
An artifact was found and tested for its carbon14 content. If 79% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? (Carbon14 has a halflife of 5,730 years.) 
Algebra
An artifact was found and tested for its carbon14 content. If 75% of the original carbon14 was still present what is its probable age to the nearest 100 years?. carbon 14 has a halflife of 5,730 years. 
algebra
An artifact was found and tested for its carbon14 content. If 75% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? (Carbon14 has a halflife of 5,730 years.) thank you 
Algebra
An artifact was found and tested for its carbon14 content. If 76% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? (Carbon14 has a halflife of 5,730 years.) 
Math
An artifact was found and tested for its carbon14 content. If 88% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. ? yr 
math
An artifact was found and tested for its carbon14 content. If 88% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
Algebra
An artifact was found and tested for its carbon14 content. If 77% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
algebra
An artifact was found and tested for its carbon14 content. If 79% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
math
An artifact was found and tested for its carbon14 content. If 81% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. yr 
algebra
An artifact was found and tested for its carbon14 content. If 84% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
math
An artifact was found and tested for its carbon14 content. If 76% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
algebra
An artifact was found and tested for its carbon14 content. If 84% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
math
An artifact was found and tested for its carbon14 content. If 83% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
math
An artifact was found and tested for its carbon14 content. If 83% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
Can some guide me
An artifact was found and tested for its carbon14 content. If 71% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? (Carbon14 has a halflife of 5,730 years.) 
Calc
A sample of a radioactive substance decayed to 93.5% of its original amount after a year. a) What is the halflife of the substance? ? years (b) How long would it take the sample to decay to 10% of its original amount? ? years 
College Math
An artifact was found and tested for its carbon14 content. If 88% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
Homework test
An artifact was found and tested for its carbon14 content. If 70% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 
applied algebra
An artifact was found and tested for its carbon14 content. If 74% of the original carbon14 was still present, what is its probable age (to the nearest 100 years)? Use that carbon14 has a halflife of 5,730 years. 1 yr 
Physics
(a)A fossilised tree was tested and contains 10 grams of Carbon14. Given that there was 12 grams of Carbon14 present when it died, determine the age of the fossil? Half life of Carbon14 is 5700 years. (b)How much Carbon14 will be present in the sample 100 years from now? 
Physics
(a)A fossilised tree was tested and contains 10 grams of Carbon14. Given that there was 12 grams of Carbon14 present when it died, determine the age of the fossil? Half life of Carbon14 is 5700 years. (b)How much Carbon14 will be present in the sample 150 years from now? 
Chemistry
Calculate the time in which the activity of an element is reduced to 90% of its original value. The halflife period of the element is 1.4*10^10 years . Answer : 2.13*10^9 years 
maths
The halflife of lead is 22 years. How long will it take for a sample of this substance to decay to 80% of its original amount 
help
the halflife of a radium is 1690 years is 90 grams is present now, how much will be present in 70 years 
Calculus
Write a differential equation to model the situation given. Do not solve. The radioactive substance neptunium139 decays to 73.36% of its orginal amount after 24 hours. How long would it take for 43% of the original neptunium to be present? What is the halflife of neptunium139? 
physics
A building has become accidentally contaminated with radioactivity. THe longest lived material in the building is strontium90 (atomic mass of 90 Sr 38 is 89.9077). If the building initially contained 5.0kg of this subtstance and the safe level is less than 10.0 counts/min, ... 
Forensics
Strontium90 is a radioactive waste product from nuclear reactors. It has a half life of 29 years. How many years would it take for a quantity of strontium90 to decay 1/16 of its original mass? 
Math
The halflife of 234U, uranium234, is 2.52 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? ? yr 
algebra
The halflife of 234U, uranium234, is 2.52 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed 
algebra
The halflife of 234U, uranium234, is 2.52 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
math
The halflife of 234U, uranium234, is 2.52 105 yr. If 97.4% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
algebra
The halflife of 234U, uranium234, is 2.52 105 yr. If 98.4% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
math
The halflife of 234U, uranium234, is 2.52 105 yr. If 98.3% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
algebra
The halflife of 234U, uranium234, is 2.52 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
Chemistry
The isotope caesium137, which has a half life of 30 years, is a product of neuclear 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 30 years 1/2 60 years 1/4 90 years 1/... 
Intermediate Maths
(a)A fossilised tree was tested and contains 10 grams of Carbon14. Given that there was 12 grams of Carbon14 present when it died, determine the age of the fossil? Half life of Carbon14 is 5700 years. (b)How much Carbon14 will be present in the sample 100 years from now? ... 
math
The halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 97.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
math
The halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 97.4% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
algebra
The halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 98.8% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
algebra
The halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 98.8% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
algebra
The halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 98.6% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
math
The halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 98.7% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? yr 
uncc
the halflife of 234U, uranium234, is 2.52 x 10^5yr. If 98.5% of thee uranium in the original sample is present, what length of time (to the nearest thousand years) has elasped 
pre algebra
The halflife of 234U, uranium234, is 2.52 105 yr. If 98.6% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
ALGEBRA
The halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 98.3% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? = 
MATH104
he halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 97.5% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? yr 
chemistry
an original sample of K40 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 halflife ok K40 in minutes? Is it 6.8328 x 10 to the 14th 
Physical Science
A gram of radioactive material has a halflife of one year. After four years how much radioactive material will be left...0g, 1/2g, or 1/4g? None of the above. The answer onehalf to the fourth power. 
Final Maths
(a)A fossilised tree was tested and contains 10 grams of Carbon14. Given that there was 12 grams of Carbon14 present when it died, determine the age of the fossil? Half life of Carbon14 is 5700 years. (b)How much Carbon14 will be present in the sample 100 years from now? ... 
AP Environmental Science (URGENT)
Strontium90 is a radioactive waste product from nuclear reactors. It has a halflife of 29 years. How many years will it take for a quantity of strontium90 to decay to 1/16 (onesixteenth) of its original mass? 
math
A material has a halflife of 12 hours. If initially there are 4 grams of the material, how much is present after 8 hours? I know the answer is 8/3, but how would you solve this using calculus? please help. 
math
solve the problem. the halflife of 234U, uranium234, is 2.52 multiplied by 105 yr. If 98.3% of the uranium in the original sample is present, what length of time (to the nearest thousand years) has elapsed? 
Math
Suppose a quantity is halvd every 18 years. use the approximate halflife formula to estimate its decay rate. is the half life equation y= 1/2^t1/2 2^1/2t= 1/y t 1/2= log2 (1/y) Where do I put 18 at? 
chemistry
Radioactive waste is difficult to dispose of due to the long time periods needed before the radiation effectively disappears. The US protocol is to store the waste for 10 halflives of the material after which the waste is no longer considered radioactive. After this time, ... 
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 ... 
Physics
1gram of redioactive material having a half life of 2years is kept in a store, calculate how much of the material will remain unchage? 
Chemistry
The cesium131 nuclide has a half life of 30 years. After 90 years, about 6g remain. What is the original mass of the cesium131 sample? 
Chemistry
Carbon14 has a halflife of 5730 years In a plant fossil you find that the 14 C has decayed to 1/8 of the original amount how long ago was this plant 
Chemistry
The halflife of hafnium156 is 0.025 s. how long will it take a 560 g sample to decay to onefourth it's original mass? 
science
A substance has a halflife of 10,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams of the substance's parent material is left? 
Physics  Half Life Question Check!!!
An ancient rock is found to contain 40Ar gas, indicating that 77% of the 40K in the rock has decayed since the rock solidified. Any argon would have boiled out of liquid rock. How long ago did the rock solidify? The halflife of 40K is 1.25 billion years. A) 2.6 billion years ... 
Math
The halflife of strontium90 is 28 years. How long will it take a 60 mg sample to decay to a mass of 15 mg? 
half life
tritium has a half life of 24.3 years .a sample of 0.1 is produced . will tthe mass of tritium change after 24.3 years 
Chemistry (Dr.Bob222)
The halflife of P32 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 equation to use for a ...