Question

​Calculate the number of molecules in 400g of calcium carbonate.(given, the atomic mass of calcium=40u, carbon=12u, oxygen=16u)

Answer 1

Dear Student,

$$\begin{gathered} \mathrm{Number}\mathrm{of}\mathrm{molecules}\mathrm{in}400\mathrm{g}\mathrm{of}\mathrm{calcium}\mathrm{carbonate}: \\ \mathrm{Number}\mathrm{of}\mathrm{molecules}=\frac{\mathrm{mass}}{\mathrm{molar}\mathrm{mass}}\times \mathrm{avagadro}\mathrm{number} \\ \mathrm{Number}\mathrm{of}\mathrm{molecules}=\frac{400}{100}\times 6.023\times {10}^{23} \\ \mathrm{Number}\mathrm{of}\mathrm{molecules}=24.092\times {10}^{23}\mathrm{molecules} \end{gathered}$$