# Strontium 90 loses 2.5% of its mass each year. What is its half life?

58,113 results

**Forensics**

Strontium-90 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 strontium-90 to decay 1/16 of its original mass?

**AP Environmental Science (URGENT)**

Strontium-90 is a radioactive waste product from nuclear reactors. It has a half-life of 29 years. How many years will it take for a quantity of strontium-90 to decay to 1/16 (one-sixteenth) of its original mass?

**Math**

Suppose strontium-90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t) = (b) Estimate the half-life of strontium. Answer: Hint: Use your...

**calculus**

Suppose strontium-90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t) = (b) Estimate the half-life of strontium. Answer: Hint: Use your...

**NEED HELP WITH CALC**

Suppose strontium-90 decays at a rate of 2 percent per year. (a) Write the fraction P of strontium remaining, as function of t, measured in years. (Assume that at time t=0 there is 100 % remaining.) Answer: P(t) = (b) Estimate the half-life of strontium. Answer: Hint: Use your...

**Calculas**

In the early 1960s, radioactive strontium-90 was released during atmospheric testing of nuclear weapons and got into the bones of people alive at the time. If the half-life of strontium-90 is 32 years, what fraction of the strontium-90 absorbed in 1965 remained in people's ...

**calculus**

In the early 1960s, radioactive strontium-90 was released during atmospheric testing of nuclear weapons and got into the bones of people alive at the time. If the half-life of strontium-90 is 27 years, what fraction of the strontium-90 absorbed in 1962 remained in people's ...

**Chemistry**

The half-life for beta decay of strontium-90 is 28.8 years. A milk sample is found to contain 10.3 ppm strontium-90. How many years would pass before the strontium-90 concentration would drop to 1.0 ppm?

**chemistry**

Strontium-90 decays through the emission of beta particles. It has a half-life of 29 years. How long does it take for 80% of a sample of strontium-90 to decay? Show process of how you got this

**Math**

The element strontium-90 is radioactive. The percent of strontium -90, A(t), left in a sample can be modelled by the half-life function A(t) = A0 (1/2)^t/29, where t represents the time, in years, after the initial time, and A0 represents the initial amount, 100% of the ...

**Chemistry**

Strontium-85, used for bone scans, has a half-life of 64 {\rm d}.How long will it take for the radiation level of strontium-85 to drop to \frac{1}{8} of its original level?

**Math**

The half-life of strontium-90 is 28 years. How long will it take a 60 mg sample to decay to a mass of 15 mg?

**chem**

Radioactive substances decay by first-order kinetics. How many years would be required for a sample containing strontium-90 to decrease to 58.32% of its initial activity? The half-life of strontium-90 is 2.88e1 years.

**Science Help**

i know that the half life of strontium 90 half-life is 28.8 but how can i explain this???

**chemistry**

Strontium-90 has half-life of 28 years. if a 1.00-mg sample was stored for 112 years. what mass of Sr-90 would remain?

**Calculus**

The half-life of radioactive strontium-90 is approximately 31 years. In 1960, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 11 percent of the original is...

**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 ...

**Calculus**

The half-life of radioactive strontium-90 is approximately 31 years. In 1960, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 11 percent of the original ...

**Math**

The half-life of radioactive strontium-90 is approximately 28 years. In 1962, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 6 percent of the original ...

**Math**

The half-life of radioactive strontium-90 is approximately 32 years. In 1961, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 8 percent of the original ...

**Science**

Can anyone help me find the half-life of strontium-90? I also need an explanation on how to do it. Thanks!! Radioactive Decay of Strontium-90: At 0 years: 100% remaining At 28 years: 50% remaining At 56 years: 25% remaining At 84 years: 10% remaining At 112 years: 5% remaining.

**Calculus**

[Exponential growth & decay] The half-life of radioactive strontium-90 is approximately 29 years. In 1965, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only ...

**math**

a life insurance agent is to be paid a commission according to the following scheme : 1000$ in year 1, half the year 1 amount in year 2, half the year 2 amount in year 3, etc. what is the total of the all amounts received by the agent in the first 5 years ?

**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%

**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 A(t)=Ao x e ^ (-0.693) (t...

**Science**

How do you find the half life of strontium 90? I know that the answer is 28.8 years but how do you arrive at that answer?

**Science**

What happens to the mass of a sample containing a radioactive element during its half-life? A. The mass decreases by half. B. The amount of mass is doubled. C. Eventually there is no mass at all. D. The mass remains the same.

**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 ...

**physics**

A building has become accidentally contaminated with radioactivity. THe longest lived material in the building is strontium-90 (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, ...

**Calculus**

If 40 milligrams of strontium-90 radioactively decays to 12 milligrams in 30 years, find its half-life (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.

**Physics (I have a test tmrw) **

The half-life of Strontium-90 is 28 a. If 60 g of this isotope is currently in a sample of soil, estimate the amount in the same sample 84 a later. So I did a=60g(1/2)^84/28 But I don't know if thats correct. Thank for your help!

**chemistry**

When 3.761g of a hydrate of strontium chloride is heated to 60 degree C it forms strontium chloride dihydrate of mass 2.746g What is the formula of the original sample?

**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 ...

**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 ...

**Chemistry**

The strontium-87 isotopes stores in the body and decays by the process shown below. The half-life is 2.80hr. Suppose that 0.766 millicuries got into the body. How many mc will remain after 8.40 hr?

**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 ...

**science**

1. What is the half-life of Strontium-90? Explain your answer. Honestly I don't know how to get this answer. I've looked it up and stuff, but I just found the answer not how to know what it is. A link or explanation would be greatly appreciated. Thanks.

**Chemistry**

The strontium-90 isotope decays by the reaction below. It has a half-life of 28 yr. If the initial activity of this isotope was 168dpm, what would the activity be after 28.0 yr?

**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 of unstable nuclide X...

**science**

what is the Half-life of strontium 90. Explain your work. Okay well I already know the answer is 28yrs but I just don't know how to explain it on how I got the answer... can you guys help me please! I need this done in 30 seconds..

**chemistry**

Find the number of disintegrations per minute emitted by 1.1 mol of 232-Th in 1 min. The half-life of 232-Th is 1.4 x 1010 year I was able to do this with the following technique: 1.1 x 6.022 x10^23 =6.62x10^23 1.4x10^10=7.358x10^15 minutes I think then it is 6.62x10^23 x 7....

**Nuclear Physics**

An investigator receives Co-60 (5.27 year half life) for use in a research study. Unfortunately the Co-60 is contaminated with Cs-137 (30.0 year half life). The initial Co-60 activity is 400 times the initial Cs-137 activity. How long after the initial assay will the Cs-137 ...

**Chemistry**

Mefenamic acid (Ponstan Forte) has a half life of 2 hours. Naproxen has a half life of 12 to 17 hours. Both are anti inflammatory drugs of apparently similar nature but could someone please explain the difference in half life? Thank you Mike

**Algebra**

The half-life of a specific radioactive compound is 20 years. The equation used to model this half-life is y = 5 1/2(t/20) where t represents time. Currently, there are 5 pounds of this compound 15 feet below the earth's surface. When will there only be 4 pounds of this ...

**chemistry**

strontium chloride can be obtained as the anhydrous salt, SrCl2, and as the hydrates SrCl2.2H20, and SrCl2.6H20. (ArSr = 87.5). 0.323 g of a sample of strontium chloride is dissolved in water and reacted with sliver nitrate solution. The mass of sliver chloride precipitates is...

**physics**

If a radioactive isotope has a half-life of 1 year, how much of the original sample will be left at the end of the 2nd year?

**Science**

if a radioactive isotope has a half-life of one year, how much of the original sample will be left at the end of the second year?

**Science**

if a radioactive isotope has a half-life of one year, how much of the original sample will be left at the end of the second year?

**Chemistry **

How many grams of a solid mixture containing strontium chloride would one need to make 558 mL of a 0.100 M strontium chloride solution, if the solid mixture contains 58.6% strontium chloride by weight

**Science**

If a loaded truck that can accelerate at 1 m/s2 loses its load and has one-half of the original mass, what acceleration can it attain from the same driving force?

**life science**

I cant grasp half life - the study guide question is how is half life dating used by scientists - I have 2 lines to write an answer

**chemistry**

What percent of the original sample of strontium-90 (half-life = 28.9 years) will remain after the following time periods?after 18 years? after 47.5 years? after 1008 years?

**half-life**

ok so i got... the half life of carbon-14 is 5730 years, the relation c+(1/2)^ N/5730 is used to calc. the concentration, c, in parts per trillion remaining n years after death determine the carbon concentration in a 11460 year old bone. please help :)

**half-life**

ok so i got... the half life of carbon-14 is 5730 years, the relation c+(1/2)^ N/5730 is used to calc. the concentration, c, in parts per trillion remaining n years after death determine the carbon concentration in a 11460 year old bone. please help :)

**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

**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 answer is 5.330. Is this ...

**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 ...

**linear/exponential**

This question involves the half-life formula. In this exercise, we are to give a half-life for an exponentially decaying quantity. Need answer to the following: The half-life of a drug in the bloodstream is 4 hours. By what factor does the concentration of the drug decrease in...

**chemistry**

Strontium has density of 2.64 and crystallizes with the face-centered cubic unit cell. Find the radius of the strontium atom

**Math**

A new car typically loses 20% of its initial value during the first year. During the second year, the car loses 15% of its value after the first year. Find the value of the car($18,000) after the first year and after the second year.

**Chemistry**

Strontium metal is responsible for the red color in fireworks. Fireworks manufacturers use strontium carbonate, which can be produced by combining strontium metal, graphite (C), and oxygen gas. The formation of one mole of SrCO3 releases 1.220 x 103 kJ of energy. a) Write a ...

**Chemistry**

The half life of U238 is 4.5 x 10^9 yr. A sample of rock of 1.6 g produces 29 dis/sec. Assuming all radioactivity is due to U238 find percent by mass of U 238. I have tried ln(t)/ln(0)= -kt and still cannot get the answer What I get is A) 4.5x10^9 x365x60x60x24=1.419x10^17 for...

**Math**

A new car typically loses 20% of its initial value during the first year. During the second year, the car loses 15% of its value after the first year. Find the value of the car after the first year and after the second year.

**Earth Science**

Why is potassium-argon dating most applicable to dating very old rocks? potassium’s long half-life potassium’s short half-life argon’s long half-life argon’s short half-life

**chem**

If the passing of three half-lives leaves 33.1 mg of a strontium-90 sample, how much was present in the beginning?

**Science**

A star's life depends on mass ___ mass=Long life Large mass= ____ life Small mass is long life and large mass is short life?

**Chemistry**

Technetium-99m is an ideal radioisotope for scanning organs because it has a half-life of 6.0 hr and is a pure gamma emitter. Suppose that 200mg were prepared in the technetium generator this morning. How many milligrams would remain after the following intervals? 1- One half ...

**Chemistry**

Technetium-99m is an ideal radioisotope for scanning organs because it has a half-life of 6.0 hr and is a pure gamma emitter. Suppose that 200mg were prepared in the technetium generator this morning. How many milligrams would remain after the following intervals? 1- One half ...

**Chemistry**

Technetium-99m is an ideal radioisotope for scanning organs because it has a half-life of 6.0 hr and is a pure gamma emitter. Suppose that 200mg were prepared in the technetium generator this morning. How many milligrams would remain after the following intervals? 1- One half ...

**chemistry**

The radius of a strontium atom is 215 pm. How many strontium atoms would have to be laid side by side to span a distance of 4.47 mm?

**chemistry**

The radius of a strontium atom is 215 pm. How many strontium atoms would have to be laid side by side to span a distance of 2.66 mm?

**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?

**Math**

The mathematician Augustus DeMorgan lived his entire life during the 1800s. In the last year of his life he announced "Once I was x years old in the year x^2". In which year was he born?

**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?

**chemistry**

A given reaction has an activation energy of 24.52 kJ/mol. At 25C the half-life is 4 minutes. At what temperature will the half-life be reduced to 20 seconds?

**Chemistry**

Why does the height of the precipitate of strontium nitrate and sodium carbonate go up as the volume of strontium nitrate increase?

**chemistry**

1-Barium sulfate and strontium sulfide both are placed into beaker of water. a- Will the strontium sulfide dissociate? ....... - If it does,write the equation showing the dissociation.

**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...

**college chemistry**

If the equilibrium constant (Keq) equals 9.12x1012 for the following reaction between strontium and magnesium: Sr(s) + Mg2+(aq)<==> Sr2+(aq) + Mg(s) Calculate Eo for a strontium=magnesium battery.

**college chemistry**

If the equilibrium constant (Keq) equals 9.12x1012 for the following reaction between strontium and magnesium: Sr(s) + Mg2+(aq)<==> Sr2+(aq) + Mg(s) Calculate Eo for a strontium=magnesium battery.

**chemistry**

If I 131 has a half-life of 8 days, what fraction will be left after a year?

**chemistry**

what is the percentage yield for Sr(NO3)2 + Na2SO4 -> SrSO4 + 2 NaNO3. mass of strontium nitrate is 0.788g mass of sodium sulfate is 1.258g mass of dry filter paper 0.759 g mass of dried precipitate in filter paper 1.317g

**help huge test friday science**

I cant grasp half life - the study guide question is how is half life dating used by scientists - I have 2 lines to write an answer

**Math**

Suppose a quantity is halvd every 18 years. use the approximate half-life 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?

**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 ...

**AP Chem**

I know this might sound easy... but i need these problems for bonus and i want to make sure they are right Silver nitrate reacts with strontium chloride in an aqueous precipitation reaction. What are the formulas of silver nitrate and strontium chloride? Write the molecular ...

**Physical Science**

A gram of radioactive material has a half-life 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 one-half to the fourth power.

**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.

**Calculus**

Radius decays at a rate of that is proportional to its mass, and has a half-life of 1590 years. If 20 g of radium is present initially, how long will it take for 90% of this mass to decay?

**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 radioactive material is ...

**chemistry**

what ins the name for SrBr2 Strontium (II) bromide strontium bromide

**math**

Suppose your bank account was worth $1000 at the beginning of last year. If your balance increased by 3% during the first half of the year and by 2% during the second half, what was your balance at the end of the year?

**Atomic physics**

1)Five possible transitions for a hydrogen atom are listed below: Select whether the atom gains or loses energy for each transition. a. Loses Gains ni = 6; nf = 4 Loses Gains ni = 4; nf = 2 Loses Gains ni = 5; nf = 3 Loses Gains ni = 2; nf = 5 Loses Gains ni = 5; nf = 7 b. ...

**science**

Cobalt-60 has a 30 year half-life. How much of an 80 gram sample would remain after 60 years?

**Math**

The U.S life expectancy of a baby born in 1960 was 69.8 years. For a birth year of 2010, the U.S life expectant was 78.5 years. Let Y be the US life expectancy for a baby born in the year x, where x=0 represents the year 1960. What would the life expectancy for a baby born in ...

**algebra**

Suppose a sample of Cesium-137 with initial mass of 200 grams decays to a mass of 160 grams voer the course of 10 years. Find the half-life of Cesium-137 (Round to the nearest year) How much Cesium-137 is left in the sample after 60 years? Round to the nearest tenth of a gram.

**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?

**Physics - Half life**

an artifact has a starting mass of C-14 of 200 g and a remaining mass of 0.78125 g. how old if the artifact? [4.58^4 years]

**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

**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