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The half-life of Palladium-100 is 4 days. After 20 days a sample of Palladium-100 has been reduced to a mass of 3 mg

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Calculus
The half-life of Palladium-100 is 4 days. After 12 days a sample of Palladium-100 has been reduced to a mass of 4 mg. What was the initial mass (in mg) of the sample? What is the mass 5 weeks after the start?

functions-math
The half-life of Palladium-100 is 4 days. A lab is working with a sample of with 3250mg. Write a function, f(x), to represent the amount of Palladium-100 left after x days

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?

Math
I need help in algebra 1. I have 4 questions, I already answered 3 of them, but I need help with the other 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). 1. Write an exponential ...

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

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

math
An unknown radioactive element decays into non-radioactive substances. In 100 days the radioactivity of a sample decreases by 64 percent. a)(a) What is the half-life of the element? half-life: b)How long will it take for a sample of 100 mg to decay to 51 mg? time needed:

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 days. Thank you for ...

chemistry
a sample of a radioisotope had a mass of 100.0 grams. After exactly 24 days, 6.25 grams remained. The half life of the isotope is _________

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 polonium? you want to ...

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? 08 days: g, 16 ...

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 days. use your equation...

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?

Chemistry
The metal palladium crystallizes in a face-centered cubic lattice with an edge length of 388.8 pm. What is the density of the palladium?

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-...

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 lives, and since a half ...

physics
The half life of a radioactive sample is 6.93 days.after how many days will only one -tenth of the sample be left behind?

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.

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?

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

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

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 ...

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?

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?

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...

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?

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?

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?

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

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

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

chemistry
Iodine-131 has a half life of eight days. What mass of iodine-131 would remain from a 20g sample after 32 days?

Physics
One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1.82252x10^24 for Part A. i need help with part...

physics
One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1.82252x10^24 for Part A. i need help with part...

chemistry
The half-life for the radioactive decay of calcium-47 is 4.5 days.If a sample has an activity of 4.00uCi after 13.5 days, what was the initial activity of the sample?

Chemistry
Hydrogen gas dissolves in palladium with the hydrogen molecules going into the spaces between the metal ions. Determine the molarity, molality, and percent by mass of the H2:Pd solution (d=10.8g/cm)containing 0.94g hydrogen gas dissolved in 215 grams of palladium metal.

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 isotopes. A 1 B 2 C 3 D ...

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

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

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?

Chemistry
a)Calculate the lattice constant a in palladium (Pd).express your answer in angstroms. b) Calculate the distance (in angstroms) between adjacent (110) planes in palladium (Pd). Hint: use your work from part (a).

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

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

physics
REALLY NEED HELP WITH THIS PLEASE. One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1.82252x10^...

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...

statistics
A professional basketball player has embarked on a program to study his ability to shoot foul shots. On each day in which a game is not scheduled, he intends to shoot 100 foul shots. He maintains records over a period of 40 days of practice, with the results below. Foul Shots ...

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

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?

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?

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

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?

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)?

Chemistry
The half-life of radon-222 is 3.82 days. If a sample of gas contains 4.38ug of radon-222, how much will remain in the sample after 15.2 days?

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

maths
Please guide me to solve the below problem: 'A'an do 2/3 of a work in 40 days.'B'can do 1/2 of the work in 75 days.'C'can do 3/4of work in 75 days.If all them together work in how many days will they do 5/6 0f the work. I had solved the above problem like this: A can do the ...

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

Chemistry
The half-life of iodine -131 is 16 days. If you start with 100 gram sample, how many half-lives have past when you have less than a gram left?

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 the sample at t=15 ...

Chemistry
(a) Calculate the lattice constant a in palladium (Pd). Use only the information available in the class Periodic Table, and express your answer in angstroms. (b) Calculate the distance (in angstroms) between adjacent (110) planes in palladium (Pd). Hint: use your work from ...

Chemistry
Po-210 Ia an alpha emitter with a half-life of 138 days. how many grams of Po-210 remain after 552 days if the sample initially contained 5.80g of Po-210?

chemistry
The half live of Iodine-131 is 8 days. if you started out with 40 mg sample of iodine-131, then what would be the mass of the sample after 32 days? please show your work

Science math
Suppose a laboratory has a 38 g sample of polonium-210. The half-life of polonium-210 is about 138 days. How many half-lives of polonium-210 occur in 1104 days? How much polonium is in the sample 1104 days later?

Math
the half-life of iodine-131 is 8 days. how much iodine-131 will be left After 35 grams sample after 32 days?

Statistics Help Please
The following data were collected on non-conformances for a period of 10 days. Day Sample Size Non-conformances 1 100 12 2 100 14 3 100 10 4 100 18 5 100 22 6 100 14 7 100 15 8 100 13 9 100 14 10 100 16 On what day is the proportion of non-conformances largest? smallest? What ...

Radioactivity
Beryllium-7 has a half-life of 53 D. A sample was observed for one minute and there were 26,880 decays. a.) what is the activity level of the sample? b.) what will the activity level of the sample be after 265 d? c.) after how many days will be activity level of the sample be ...

science
Suppose a laboratory has a 31 g sample of polonium-210. The half-life of polonium-210 is about 138 days. How many half-lives of polonium-210 occur in 966 days? How much polonium is in the sample 966 days later?

sciencemath
Suppose a laboratory has a 31 g sample of polonium-210. The half-life of polonium-210 is about 138 days. How many half-lives of polonium-210 occur in 966 days? How much polonium is in the sample 966 days later?

physics
After 1.84 days, the activity of a sample of an unknown type radioactive material has decreased to 85.8% of the initial activity. What is the half-life of this material? (in days)

chemistry
Iodine-131, a beta emitter, has a half-life of 8 days.How many grams of a 10.0g sample of iodine-131 would remain after 56.0 days?

Chemistry
The radioisotope radon-222 has a half-life of 3.8 days. How much of a 98.4 g sample of radon -222 would be left after approximately 19 days?

Chemistry
Radon-222 is a radioactive gas with a half-life of 4 days. Approximately how much of a 40 g sample of radon-222 would remain after 12 days?

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...

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 ...

Chemistry
a) 45.02% of the sample remains after 85 days. Consider how you can use the percent of Ir-192 remaining and the number of days to calculate the mass remaining after 85 days.

Engineering Math
An unknown radioactive element decays into non-radioactive substances. In 120 days the radioactivity of a sample decreases by 59 percent. What is the half life of the element? How long will it take for a sample of 100 mg to decay to 77 mg? The answer is not 93 day, I ...

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 ...

Calculus-Modeling Equations
An unknown radioactive element decays into non-radioactive substances. In 420 days the radioactivity of a sample decreases by 39 percent. 1.What is the half-life of the element? 2.How long will it take for a sample of 100 mg to decay to 46 mg?

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 3.125 millicuries. 56 ...

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

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

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 ...

science
the half-life of iodine-131 is 8 days. how much iodine-131 will be left after 8 days if you have an initial mass of 1g ?

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?

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)

College Math
In West Virginia, 100 days of the year (365)have temperatures less than32 degrees Fahrenheir. What (reduced) fraction of the days is that? I'm not sure how to go about finding the answer. Can you please help?

Math
The population of termites and spiders in a certain house are growing exponentially. the house contains 100 termites the day you move in. After 4 days, the house contains 200 termites. Three days after moving in, there are two times as many termites as spiders. Eight days ...

Chemistry
Palladium-107 undergoes â decay (t1/2 = 6.5 x 105 yr) to form silver-107. How long will it take for 0.150 mol of silver-107 to form from 1.25 mol of palladium-107? help please...thank you :)

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?

Science
Iodine-131 is used I'd diagnosing certain medical problems because of the short half-life, which is 8.02 days. Assume the hospital lab uses for 4.52g of iodine-131 in a month. What mass of this radioisotope remains in patients after 32 days?

physics
Suppose 32000 radioactive nuclei are in a sample. About how many remain after two days if the half-life is 22 hrs? What is the initial activity of the sample in decays per minute?

Chemistry
Static charge can interfere with the production of plastic products by attracting dust and dirt. to reduce it, manufacturers expose the area to polonium-210, which has a half-life of 138 days. How much of a 25.0-g sample will remain after one year (365 days)? N = N0(1/2)t/T...

physics-Radioactivity
1) The number of radioactive nuclei in a particular sample decreases over a period of 15 days to one-seventeenth the original number. What is the half-life (in days) of these nuclei? 2) What is the activity of a sample of 14C that contains 1.22E+21 nuclei?

chemistry
Iron-59 has a half-life of 45.1 days. How old is an iron nail if the Fe-59 content is 25% that of a new sample of iron? Show all calculations leading to a solution. Is this how you would do this? (100/25) = 0.693 times (45.1) 4= 31.2543 final answer is 7.8136

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?

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 (c) What is the half-...

Algebra
Two different radioactive isotopes decay to 10% of their respective original amounts. Isotope A does this is 33 days, while isotope B does this in 43 days. What is the approximate difference in the half-lives of the isotopes? 3 days 10 days 13 days 33 days

Science/Chemistry
22Na has a half-life of 951 days. How many grams of a 1.00 kg sample would be left after 4 years?

chemistry
The radioactive isotope, phosphorus-32, has a half-life of 14.26 days. How much phosphorus-32 will remain after 60 days? Please help.

Algebra 2 help...
A half life of a certain radioactive is 36 days. An initial amount of the material has a mass of 487 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 5 days. Round your answer to the nearest thousandth.

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