Some Basic Concepts of Chemistry

To determine the concentration of a $\mathrm{CaCO}_3$ solution in molarity ( $\mathrm{mol}/\mathrm{L}$ ), given its concentration is 1000 ppm , we proceed as follows:Mass of $\mathrm{CaCO}_3$ in 1 Liter:Since 1000 ppm means 1000 mg of $\mathrm{CaCO}_3$ per liter, it converts to grams as:$\;\frac{1000 \times 1000\ \mathrm{mg}}{1000000}=1\ \mathrm{g}$Calculation of Moles:The molar mass of $\mathrm{CaCO}_3$ is calculated using the atomic masses:$\mathrm{Ca}=40\;\text{ u},\ \mathrm{C}=12\;\text{ u, }\ \mathrm{O}=16\;\text{ u. }$Therefore, the molar mass of $\mathrm{CaCO}_3=40+12+(16 \times 3)=100\ \mathrm{g}/\mathrm{mol}$.Now, calculate the number of moles ( $n$ ):$n=\frac{\;\text{ Mass of }\;\; \mathrm{CaCO}_3}{\;\text{ Molar mass }\;}=\frac{1}{100}=0.01\ \mathrm{mol}$Determine Molarity:The molarity (concentration in $\mathrm{mol}/\mathrm{L}$ ) is given by:$\;\text{ Molarity }\;=\frac{\;\text{ Number of moles }\;}{\;\text{ Volume of solution in }\; \mathrm{L}}=\frac{0.01}{1}=0.01\ \mathrm{mol}/\mathrm{L}=10^{-2}\ \mathrm{mol}/\mathrm{L}$Thus, the concentration of the $\mathrm{CaCO}_3$ solution is $10^{-2}\ \mathrm{mol}/\mathrm{L}$.