Pregnant women take 250 mg tablets of as a supplement. The ion present in those pills is poisonous to small children. The ingestion of ion will kill a child. What is the minimum number of whole tablets a 89 ib child needs to ingest to become fatally poisoned?

Question

Pregnant women take 250 mg tablets of as a supplement. The ion present in those pills is poisonous to small children. The ingestion of   ion will kill a child. What is the minimum number of whole tablets a 89 ib child needs to ingest to become fatally poisoned?

aaronq · Answer

The ingestion of 550 mg Fe ion will kill a 22 lb child.

find how many tablets you need to have in total 550 mg Fe.

aaronq · Answer

You need to find the mass percent composition of Fe in FeSO4 first. http://www.chem.tamu.edu/class/majors/tutorialnotefiles/percentcomp.htm

anonymous · Answer

36.7%? is mass percent?

anonymous · Answer

also, how to find how many tablets I need that has a total of 550 mg Fe?

aaronq · Answer

is that what you calculated?

aaronq · Answer

325 mg tablet * mass% of Fe= mass of Fe per pill

then just divide, 550 mg/mass of Fe per pill

anonymous · Answer

4.6 = 5? Thanks! But what was the logic of finding mass percent and multiplying it? Shouldn't the units both be Mg? The units don't match

aaronq · Answer

you should definitely have to be using the same units, i didn't think i needed to explicitly mention this. 

"4.6 = 5?" what does this mean?

anonymous · Answer

Opps the answer is 5. (rounded up) sorry. it was multiple choice.

aaronq · Answer

The logic of finding the mass percent is to find the percent of the mass of FeSO4 that is actually just Fe, without the S or O's

anonymous · Answer

Oh, thanks! But why are you allowed to multiply it?  The units aren't the same?

aaronq · Answer

mass percent doesn't have units.

aaronq · Answer

it's a percent.

anonymous · Answer

oh. I see. Thanks then! I appreciate the help :)