Question

Calculate the number of molecules in 250 mg tablet of CaCO3

Answer 1

Molar mass of CaCO₃ = 100 g mol^-1
100 g of CaCO₃ contains = 6.022$\times$10²³ molecules
1 g = 1000 mg
250 mg of CaCO₃ contains = $\frac{6.022\times {10}^{23}\times 250\times {10}^{-3}}{100}$ = 15.05$\times$10²⁰ molecules