The solubility product of Mg(OH)2 is 1.2 × 10-11. What minimum OH^- concentration must be attained (for example, by adding NaOH) to decrease the Mg^2+ concentration in a solution of Mg(NO3)2 to less than 1.0 × 10-3 M FeSO4.

What does that mean you dum bum

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.