It will take between 450 and 525 years.
a sample is brought to the laboratory and the chemist determines the percentage of the daughter isotope is 87.5%. if the half-life of the isotope is 150 million years, how old is the sample?
Uranium 235 is 0.7 percent of natural uranium and is fissile
Yes U235 is the fissionable isotope of Uranium. Natural Uranium contains only about 0.7 percent U235, which is enough to produce fission only with a good moderator such as graphite or heavy water. In light water reactors the Uranium has to be enriched to about 4 percent U 235.
Nitrogen 14 is by far the most abundant isotope (99.63% abundant).An easy way to figure out which one is the most abundant is to look at the periodic table. The mass on the periodic table is the weighted average of all possible isotopes. The atomic mass of nitrogen is 14.00674. You can gather from this that the most abundant isotope is N-14, since the number is VERY close to 14.It is also possible to guess the most common isotope if you do not have access to a periodic table. Nitrogen has 7 protons and the most stable isotope is Nitrogen 14, which has 7 neutrons in addition to the protons. In virtually all elements, the stable isotopes are those that have the same or very similar number of neutrons as the number of protons in the nucleus. This works for Carbon which has 6 protons and 6 neutrons in the nucleus for Carbon 12, the most common isotope.This is also true for Oxygen 16 (8P and 8N), Silicon 28 (14P and 14N), and just about any element you choose.An isotope of nitrogen containing seven neutrons would be nitrogen - 15.
3.88 billion years
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.
That is done to calculate the weighted average.
Calculation of the atomic weight of an element having many isotopes:ia - atomic mass of the isotope a x percent concentration of the isotope in the elementib - atomic mass of the isotope b x percent concentration of the isotope in the elementic - atomic mass of the isotope c x percent concentration of the isotope in the element...........................................................................................................................iz - mass of the isotope z x percent concentration of the isotope in the elementMake the sum: I = ia + ib + ic + ..... izThe atomic weight of the element is: I/100 (the term weight is recommended by IUPAC in this case).
a sample is brought to the laboratory and the chemist determines the percentage of the daughter isotope is 87.5%. if the half-life of the isotope is 150 million years, how old is the sample?
5%
19.9
248.90
Uranium 235 is 0.7 percent of natural uranium and is fissile
12.5% is remaining.
Take percent abundance times atomic mass for each isotope then add all up for average atomic mass.
the half-life
the atomic mass is -(248.90)