How many moles of $Al_2(SO_4)_3$ are present in $50 \ g$ of the substance?

The number of sodium atoms in $2$ moles of sodium ferrocyanide is

The number of moles of water present in a spherical water droplet of radius $1.0 \ cm$ is,(Given: Density of water in the droplet $= 1.0 \ g \ cm^{-3}$)

Total number of atoms represented by the compound $CuSO_4 \cdot 5H_2O$ is

Find the number of millimoles for $0.160 \ g$ sodium hydroxide.

From $44 \ mg$ of $CO_2$,$2 \times 10^{20}$ molecules of $CO_2$ are removed. The number of molecules of $CO_2$ left are (Given $N_A = 6 \times 10^{23}$):-