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If I take a radioactive sample of 400 moles of an unknown substance and let it decay to the point of three half-lives I would have 50 moles left of the sample. 1/2 of what is left will decay in the next half-life. At the end of that half-life I will have 25 moles left of the unknown substance or 4/25.
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What is the percentage of radioactive nuclei left after 3 half lives have passed?
12.5%
How fast a radioactive element decays is given by is what?
The decay of a radioactive element is governed by its half-life, which is the time it takes for half of the radioactive atoms in a sample to decay. Different radioactive elements have different half-lives, ranging from microseconds to billions of years. The decay rate is exponential, meaning that the rate of decay decreases over time as the amount of remaining radioactive material decreases.
A radioactive sample has a half-life of 5.0 min What fraction of the sample is left after 20 min?
After 20 minutes, there have been 4 half-lives (20 min / 5 min per half-life). Each half-life reduces the sample by half, so the fraction of the sample left after 20 minutes is (1/2)^4, which is 1/16. Therefore, 1/16 of the original sample is left after 20 minutes.
What is the half life of a radioactive substance if 2.4G decays to 1.80G in 66 hours?
The half-life of a radioactive substance that decays from 2.4g to 1.8g in 66 hours is 159 hours. AT = A0 2(-T/H) 1.8 = (2.4) 2(-66/H) 0.75 = 2(-66/H) log2(0.75) = log2(2(-66/H)) -0.415 = -66/H H = 159
What fraction of a radioactive sample remains after one half-life?
Half of the original sample of a radio isotope remains after a half-life period. After two half-life periods, one-fourth of the radio isotope remains.
After three half-lives what fraction of a radioactive sample will remain?
Approx 1/8 will remain.
What percentage of a radioactive sample remains after 5 half-lives?
After 5 half-lives, 3.125% (or 1/2^5) of a radioactive sample remains. Each half-life reduces the sample by half, so after 5 half-lives, there is only a small fraction of the original sample remaining.
What part of a radioactive sample remains unchanged after 2 half lives?
After 2 half lives, 25% of the original radioactive sample remains unchanged. This is because half of the sample decays in each half life, so after 1 half life, 50% has decayed, and after 2 half lives, another 50% has decayed, leaving 25% unchanged.
After three half-lives what fraction of a radioactive sample remains?
1/8 of the original amount remains.
Why After three half-lives what fraction of a radioactive sample remains?
After three half-lives, only 1/8 (or 12.5%) of the original radioactive sample remains. This is because each half-life reduces the amount of radioactive material by half, so after three half-lives, you would have (1/2) * (1/2) * (1/2) = 1/8 of the original sample remaining.
What fraction of a radioactive sample remains after three half-lives?
Not sure what you mean by "had-lives". After 3 half lives, approx 1/8 would remain.
What is the percentage of radioactive nuclei left after 3 half lives have passed?
12.5%
What does the half life of a radioisotopes indicate?
The half life of a radioisotope indicates the rate of decay for a radioactive sample
What fraction of a sample remains after three half lives?
An eighth remains.
Determine the amount of time it takes for three fourths of a radioactive sample of an isotope to decay?
The half-life is 4 days. That means half of it will be gone in 4 days, and that leaves half of the original sample. In another 4 days, half of the remaining half will have decayed. And that will leave only 1/4 th of the original sample. That means 3/4 ths of the original sample will have decayed. In 8 days, three fourths of a sample of a radioactive element with a half-life of 4 days will have decayed.
How fast a radioactive element decays is given by is what?
The decay of a radioactive element is governed by its half-life, which is the time it takes for half of the radioactive atoms in a sample to decay. Different radioactive elements have different half-lives, ranging from microseconds to billions of years. The decay rate is exponential, meaning that the rate of decay decreases over time as the amount of remaining radioactive material decreases.
What is the half-lifeof 100.0g sample of nitrogen-16 that decays to 12.5 g of nitrogen-16 in 21.6 s?
The half-life is the time it takes for half of a radioactive sample to decay. In this case, the sample of nitrogen-16 decays from 100.0 g to 12.5 g, which involves three half-lives (100 g to 50 g, 50 g to 25 g, and 25 g to 12.5 g). Since this decay occurs over 21.6 seconds, we can calculate the half-life by dividing the total time by the number of half-lives: 21.6 s / 3 = 7.2 s. Therefore, the half-life of nitrogen-16 is 7.2 seconds.
