Which of the following has the greatest mass in grams? a. 0.5 mol lead (pb) atoms b. 1 mole of hydrogen (h) atoms c. 1 atom of silver (ag) d. 25 atoms of iron (fe)

A. 0.5 mol lead (pb) atoms Let's look at the options and see how much they each weigh. A. 0.5 mol lead (pb) atoms * Lead is pretty heavy with an atomic weight of over 200, so this would be a bit over 100 grams. B. 1 mole of hydrogen (H) atoms * Twice as many atoms, but hydrogen only weighs about 1 gram per mole. So A is still has the most mass. C. 1 atom of silver (Ag) * Gotta laugh at this. 1 atom? I don't care how heavy it is, it's gonna have a hard time with about 10^23 lead atoms. So A still has the most mass. D. 25 atoms of iron (Fe) * With that factor of 10^23 going for lead because we're using a half mole, 25 atoms of iron just won't cut it. So of the available choices, we have about 100 grams of lead, about 1 gram of hydrogen. And an unmeasurably small amount of silver and iron. Lead wins easily.