# If an isotope with a half life of 10 minutes and a starting sample size of 100 g would have how many grams remaining after 30 minutes?

The sample will have 12,5 grams.

### What is the half life of an isotope if 125g of a 500g sample of the isotope remains after 3.0 years?

### If the isotope have short half lives is that mean that the isotope is in a stable condition?

No. Only radioactive elements have half-lives, the half-life is the time that it will take for half of the atoms in a sample of a radioactive isotope to decay into another element or isotope. This is a constant property of the isotope and does not depend on the sample size. Stable isotopes never decay.

### What is the half-life of a radioactive isotope?

The half-life of a radioactive isotope is the length of time for one half of a given sample to decay into another isotope (usually of a different element). It is a logarithmic process. After 1 half-life, there is half of the sample remaining; after 2 half-life's there is one quarter of the sample remaining; after 3, one eighth, etc. Each isotope has a different half-life, ranging from femtoseconds to billions of years. The equation for…

### Can you predict when a specific atom will decay?

No. The time it will take for an individual unstable atom to decay is completely random and impossible to predict. However, because there are so many atoms in a sample (6.02x1023 in one mole) it is possible to observe the half-life of the atoms. The half-life is the time that it will take for half of the atoms in a sample of a radioactive isotope to decay into another element or isotope. This is a…

### What is the half life of an isotope if 125g of a 500g sample o the isotope remains after 30 years?

If 125g of a 500g sample remains after 30 years, then 0.25 of the original sample remains after 30 years. By inspection alone, you can see that the half-life is 15 years, i.e. after 15, 30, 45, and 60 years, you would expect 0.5, 0.25, 0.125, and 0. 0625 of the original to remain. Formally, the equation is ... AT = A0 2(-T/H) ... where A0 is starting activity, AT is activity after some time…

### What is the use of measuring the activity of a radioactive isotope in a sample to determine its age?

### What is the formula to calculate the half-life of a radioactive isotope?

The following formula can be used to calculate half-life (t1/2): t1/2 = (t ln 1/2)/(ln mf / mi) t = time that has passed mf = the final or remaining mass of undecayed sample mi = the initial or original mass of undecayed sample (The fraction mf / mi is of course equivalent to the fraction of undecayed sample remaining, in case you are given the fraction remaining rather than specific masses.) Note: You can…

### What is the half-life of a radioactive sample of bromine-74 in 25 minutes in a 4mg sample?

The question does not make sense. The half-life of bromine-74 is, in fact, 25.4 minutes. In 25 minutes, that 4mg sample will decay to 2mg. In 25 more minutes it will decay to 1mg. In 25 more minutes it will be 0.5mg. And so on and so forth. If you meant to ask how much will remain after a given period of time, please restate the question.

### A certain isotope of uranium has half life of 4years after 12 years how many kg of isotope will remain from original sample of 100kg?

If a radioactive isotope has a half-life of 4 years, than 0.125 (0.53) of the isotope will remain after 12 years, or 3 half-lives. The question asked about Uranium. There is no isotope of Uranium with a half-life of 4 years. The closest is 232U92, which has a half-life of 68.9 years. Reference: http://www.nndc.bnl.gov/chart/

### Why can gaseous isotopes of an element can be separated by diffusion?

Each isotope has a characteristic mass that is distint from the mass of any other isotope. An isotope with a lower mass difuses more rapidly than one with a higher mass. Although the difference is usually small,many sequential diffusion stages can result in an almost pure sample of one isotope. This was the method by which the uranium-235 isotope in natural uranium was sufficiently concentrated to make the first atomic bomb.