[jokerjkm]

help me please!

Chlorophyll contains 2.72% Mg by mass. Assuming one Mg atom per chlorophyll molecule, what is the molecular mass of chlorophyll.

[Otis]

Nasty problem you bet, but here's a try

100.0 g of chlorophyl contains 2.72 g Mg, ok? (from the percentage)

so, Find the mol of Mg, then mol chlorophyl, then mass / mole chlorophyl

You try first. (answer below)


2.72 g Mg  x    1 mol Mg   = 0.112 mole Mg = 0.112 mol chlorophyl
                   24.31 g Mg

So,    100.0 g chlorophyl    = 894 g/mol chlorophyl
       0.112 mol chlorophyl

That was fun,

Otis
hey