Question

What is the mass (in grams) of 2.5 moles of slaked lime,$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$?

Answer 1

Step 1: Calculating the molecular mass of slaked lime,$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$:-

The molecular mass of 1 mole of slaked lime, $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$ is

$=40+(16+1)\times 2=40+34=74\mathrm{g}$

Step 2:- Calculating the mass of 2.5 moles of slaked lime$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$:-

Since 1 mole of slaked lime weighs $74\mathrm{g}$

$\therefore$2.5 moles of slaked lime is $$\begin{gathered} =2.5\times \mathrm{Molecular}\mathrm{mass}\mathrm{of}\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\mathrm{g} \\ =2.5\times \{40+(16+1)\times 2\} \\ =2.5\times \left(74\right) \\ =185\mathrm{g} \end{gathered}$$

Hence, The mass of 2.5 moles of slaked lime, $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$ in grams is $185\mathrm{g}$