Half life is defined as the time when the final concentration reduced to half of the initial value.
Thus, for first half life, the remaining percentage of the reactant is 50 percent that is 
Now, for second half life, the remaining percentage will be 50 percent of the remaining 50 percentage that is
or 
Thus, general formula for n half lives =
Now, 98.4 years is equal to eighth times 12.3 years that is
=
remaining material.
Therefore, mass of the nuclide will remain after 98.4 years= 
= 
Mass of remaining nuclide after 98.4 years = 
Hydroxide ion concentrstion in bleach is higher
Deviations in Ideal gas behavior increase at higher pressures and lower temperatures.
There are 1.50 x10^6 atoms of nitrogen in 10 grams of NH4NO3. You convert the grams to moles first and then using the definition of a mole you determine the number of molecules.