Answer
There are necessary 2.5 g of $KCl$ to prepare 50. g of that solution.
Work Step by Step
1. Identify the conversion factors:
- Since the $KCl$ solution is 5.0% (m/m):
5.0 g (Solute) = 100. g (Solution)
So: $\frac{5.0 \space g \space (Solute)}{100. \space g \space (Solution)}$ and $\frac{100. \space g \space (Solution)}{5.0 \space g \space (Solute)}$
2. Calculate the mass of solute needed to prepare 50. g of that solution:
$50. \space g \space (Solution) \times \frac{5.0 \space g \space (Solute)}{100. \space g \space (Solution)} = 2.5 \space g \space (Solute)$
