The half-life of radon-222 is 3.82 days. if a sample of gas contains 4.38 μg of radon-222, how much will remain in the ample after 15.2 days?

Explanation:

We can write the amount of mass of radon-222 left after a time t by using the equation:

where

is the initial mass

t is the time

is the half-life

Substituting t = 15.2 d in the formula, we find

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.