To calculate the number of molecules in <span>6.00 moles of hydrogen sulfide, H2S, the equivalence factor used is Avogadro's number equal to (6.022 x 10^23 molecules/mole). The answer is 6</span>.00 moles of hydrogen sulfide * <span>(6.022 x 10^23 molecules/mole) equal to 3.61 x10^24 molecules.</span>
The atoms of some chemical elements have different forms, called isotopes. These break down over time in a process scientists call radioactive decay. Each original isotope, called the parent, gradually decays to form a new isotope, called the daughter. Each isotope is identified with what is called a ‘mass number’. When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.