A percent solution is not simply a matter of adding a certain volume of liquid to the weight of a material. A percent solution is the concentration of a soluble material (solute) in parts per hundred of the total solution.
Originally Posted by menglert
To make a percent solution of anything, weigh the desired percentage amount of your soluble material and place it into your beaker or graduate. Slowly add your solvent while dissolving the soluble material and bring the total volume up to 100ml.
In other words, to make 100ml of a 20% potassium chloroplatinite solution, weigh 20g of potassium chloroplatinite, dump it into your graduate and add water while dissolving the potassium chloroplatinite bringing the total volume up to 100ml.
Weighing 2g and adding water to bring the total volume up to 10ml is what you're looking for.