A 300. g block of phosphorus-32, which has a half-life of 14.3 days, is stored for 100.1 days. At the end of this period of time, what mass in grams of phosphorus-32 remains?

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

sure im new too!

explanation:

the answer is 0.42 is that is an option. this question provides no info