"Hot" Water I have this problem in class that I could not solve. Could some one please help me? I have 100mL of water made with tritium (radioactive isotope of hydrogen). If I were to pour this 100mL of hot water into the ocean (given the volume of the ocean is 1.3*(10^18)m^3) how many molcecules of the original 100mL of ditritium monoxide would be in a 100mL sample of the ocean water. Assume the tritium oxide has mixed thoroughly. As this question deals with grams and molecules, I expect it to have something to do with avogadro's constant. Please suggest a few steps so that I can solve the problem. Thanks!