Establish the molality equation and determine the mass of KCl needed to make 126 g of 0.505 m KCl

Recall that molality can be calculated as:

$\overline{){\mathbf{molality}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}\frac{\mathbf{moles}\mathbf{}\mathbf{of}\mathbf{}\mathbf{solute}}{\mathbf{kg}\mathbf{}\mathbf{of}\mathbf{}\mathbf{solvent}}}$

In this case, the molality is already given where:

How much dry solute would you take to prepare each of the following solutions from the dry solute and the solvent?

126 g of 0.505 m KCl