Question

Chlorophyll, the substance responsible for the green color of leaves, has one magnesium atom per chlorophyll molecule and contains 2.72% magnesium by mass. What is the molar mass of chlorophyll ?

Answer 1

Dear Student,

$$\begin{gathered} 1\mathrm{Mg}\mathrm{atom}\mathrm{is}\mathrm{present}\mathrm{in}1\mathrm{molecule}\mathrm{of}\mathrm{chlorophyll} \\ 1\mathrm{molecule}\mathrm{of}\mathrm{chlorophyll}\mathrm{contains}2.72\%\mathrm{magnesium}\mathrm{of}\mathrm{entire}\mathrm{mass}\mathrm{of}\mathrm{chlorophyll} \\ \mathrm{Therefore},\mathrm{we}\mathrm{can}\mathrm{say}\mathrm{that} \\ 2.72\%\mathrm{of}\mathrm{molar}\mathrm{mass}\mathrm{of}\mathrm{chlorophyll}=\mathrm{atomic}\mathrm{mass}\mathrm{of}\mathrm{Mg} \\ \mathrm{or},\frac{2.72}{100}\times \mathrm{Molar}\mathrm{mass}\mathrm{of}\mathrm{chlorophyll}=24.31 \\ \mathrm{or},\mathrm{Molar}\mathrm{mass}\mathrm{of}\mathrm{chlorophyll}=\frac{24.31\times 100}{2.72}=894\mathrm{g} \end{gathered}$$