The odor of a smelly shower drain can be eliminated by removing debris from the drain. Discarding the odor-causing material in the garbage outside the home ensures the smell does not invade other areas. Boiling water dissolves oils and grease deposited on the sides of the pipe in the drain, which add to the smell.
Luckily for us, Nernst derived an equation that allows us to determine at what point the two forces (chemical and electrical gradients) balance each other - in other words, at what point we have an ionic equilibrium.
So when you see radioactivity equations on the SAT II Chemistry test, one of the most important things to remember is that the sum of the mass numbers and the sum of the atomic numbers must both be equal on both sides of the equation.