Chlorophyll, the green colouring matter of plants responsible for photosynthesis, contains `2.68%` of magnesium by mass. Calculate the number of magnesium atoms in `2.00 g` of chlorophyll.

Options

A. `1.345xx10^(21)`
B. `1.345xx10^(20)`
C. `13.45xx10^(21)`
D. `1.345xx10^(23)`

Answer

A

Explanation

`:' 100g `chlorophyll contains `2.68g Mg=(2.68)/(24)` mole `Mg`
`:. 2g` chlorophyll contains `(2.68xx2)/(24xx100)` mole `Mg=2.2xx10^(-3)`mole `Mg`
No. of `Mg` atoms `=2.2xx10^(-3)xx6.023=1.345xx10^(21)` atoms of `Mg`.