12.5% is remaining.
Do you mean carbon dating? Carbon dating is a process that scientists use to try to ascertain the age of an item by analyzing the amount of a radioactive carbon isotope that is present in the item. Generally this is used to date biological items. Like, really old trees and stuff. The percent of the radioactive isotope in the specimen is accumulated to normal levels as the thing was alive, after it is dead it stops absorbing new carbon and thus by measuring the ratio of isotopes that are decaying we can determine the age of the item. (using the half-life of the radioactive isotope)
The most useful isotope is uranium 235 which occurs naturally as 0.7 percent uranium as found. Plutonium 239 is also useful but has to be made in a reactor from uranium 238
Every two years half of the parent (the original) isotope decays into the daughter isotope. Therefore, after just two years, 50% of the parent isotope will remain. In another half life (two years), half of that 50% will remain. Therefore, in four years two half lives have passed and 25% of the parent isotope remains.
One half-life.
0.780 Atm
the half-life
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.
Do you mean carbon dating? Carbon dating is a process that scientists use to try to ascertain the age of an item by analyzing the amount of a radioactive carbon isotope that is present in the item. Generally this is used to date biological items. Like, really old trees and stuff. The percent of the radioactive isotope in the specimen is accumulated to normal levels as the thing was alive, after it is dead it stops absorbing new carbon and thus by measuring the ratio of isotopes that are decaying we can determine the age of the item. (using the half-life of the radioactive isotope)
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).
5%
2.156
19.9
248.90
The most useful isotope is uranium 235 which occurs naturally as 0.7 percent uranium as found. Plutonium 239 is also useful but has to be made in a reactor from uranium 238
Uranium 235 is 0.7 percent of natural uranium and is fissile
Natural uranium contain 0,7204 % uranium 235.