"chlorophyll a" chemistry problem?

Question

Chlorophyll a is essential for photosynthesis. It contains 2.72% magnesium by mass. What is the molar mass of chlorophyll a assuming there is one atom of magnesium in every molecule of chlorophyll a?

Can anyone lead me in the right direction? I'm a little lost.

Answer 1

http://www.youtube.com/watch?v=gQp7ZDtR0...

Answer 2

This is more of a math problem then a chemistry one. You have chlorophyll a molecule with a atom of magnesium in it.

The atomic mass of magnesium is 24.31. We know the 2.72% of the entire mass of chlorphyll a is the mass of one Mg.

24.31amu = (.0272) *(chlorophyll a molar mass)

chlorophyll a molar mass = 893.75amu

This is middle school math and I had to think about it my self too. What I did to make it easier, is make a hypothetical example.



You have 27 potatoes. And 27 potatoes is 6.0% of the total number of potatoes at the market. So:

(Total number of potatoes) * (.06) = 27 potatoes

Total number of potatoes = 450

Chlorphyll? Sounds more like bore-o-phyll. lol