Atomic weight of an element can be calculated as follows: average atomic weight = (atomic weight of first isotope)(its percentage of abundance) + (atomic weight of second isotope)(its percentage of abundance)
average atomic weight = 98.225 amu atomic weight of first isotope = 97.780 amu its percentage of abundance = 1 - 0.417 = 0.583 atomic weight of second isotope = ?? its percentage of abundance = 0.417
So, just substitute in the above equation to get the atomic weight of the second isotope as follows: 98.225 = (97.78)(0.583) + (mass2)(0.417) atomic weight of second isotope = 98.847 amu
Chemical reactions often involve changes in energy due to the breaking and formation of bonds. Reactions in which energy is released are exothermic reactions, while those that take in heat energy are endothermic.
