The half-life of a radioactive substance is the time that it takes for half of the atoms to decay. With a half-life of 10 days, half has decayed in this time. After 20 days, a further 10 days/another half life, a further half of the remainder has decayed, so 1/4 of the original material remains, 1/4 of 15g is 3.75 grams. This is the amount of original radioactive substance remaining, but it’s daughter isotope ( what the decay has produced ) is also present, so the original sample mass is effectively constant, especially in a sealed container. Even in an unsealed container, and assuming alpha ( helium nucleii) emission, a drop in mass per radioactive atom of 4 Atomic Mass units, compared with the original atom of, say 200 amu is only 2% mass decrease, less for heavier decaying nucleii.
A half life may or may not be a fraction. The half life of carbon 14, for example, is 5715 years - not really a fraction, unless you are thinking in terms time periods which are much longer than a year.
No, the size of a radioactive sample does not affect its half-life. The half-life is a characteristic property of a radioactive isotope, defined as the time it takes for half of the radioactive atoms in a sample to decay. This property is intrinsic to the isotope itself and remains constant regardless of the amount of material present. Thus, whether you have a small or large sample, the half-life will remain the same.
we need to know the units of 20. Is it grams, kilograms, %...
The half-life of a radioactive nuclide when 95% of it is left after one year is 13.5 years. AT = A0 2(-T/H) 0.95 = (1) 2(-1/H) ln2(0.95) = -1/H H = -1/ln2(0.95) H = 13.5
Luckily got it on my last try it was apparently 65.39%
6.25
After 10 hours, 25% of the radioactive substance remains because each half-life reduces the amount by half. So, after the first 5 hours, 50% remains, and after the next 5 hours, half of that amount remains, which is 25%.
The half-life of a radioactive isotope is defined as the time taken for the isotope to decay to half of its initial mass. So to decay to 50 percent of its initial mass will take one half-life of the isotope. One half-life of the isotope is 10 hours so the time taken to decay is also 10 hours.
The temperature The total amount of the substance The addition of a catalyst ~
6 hours. you have a hot one there!
A. The half-life of a radioactive substance is determined by the specific decay process of that substance, so it is not affected by the mass of the substance or the temperature. B. The mass of the substance does not affect the half-life of a radioactive substance. C. The addition of a catalyst does not affect the half-life of a radioactive substance. D. The type of radioactive substance directly determines its half-life, as different substances undergo radioactive decay at varying rates.
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
The half-life of a radioactive substance is the time it takes for half of the atoms in a sample to decay. It is a constant characteristic of each radioactive isotope. After one half-life, half of the original substance will remain, and the other half will have decayed into other elements.
Its 5 hours. 50% of the substance is decayed at 10 hours (that is what half life means. It's full life is 20 hours). Multiple 75% times 20 hours to find that 75% is 15 hours. Subtracrt 15 hours from 20 hours to get the answer of 5 hours for the decay of 75% of the substance.
External factors such as temperature, pressure, and chemical reactions do not affect the half-life of a radioactive substance. The decay rate of a radioactive isotope remains constant over time regardless of these external conditions.
Water itself does not have a radioactive half-life because it is not a radioactive substance. The concept of half-life applies to radioactive materials that undergo radioactive decay.
The average time needed for half of the nuclei in a sample of a radioactive substance to undergo radioactive decay is called the "half-life." This period is a characteristic property of each radioactive isotope and varies significantly between different substances. During one half-life, the quantity of the radioactive material reduces to half of its original amount.