A laboratory technician must prepare a solution of sodium carbonate decahydrate, Na2CO3⋅ 10 H2O to perform some analyzes. (The 10 water molecules involved in the knowledge of crystallization that are part of the substance.) The laboratory manager quickly writes the following indications on a sheet of paper: Prepare 250 ml of 0.0500 M solution of sodium carbonate decahydrate, Na2CO3⋅ ⋅ ⋅⋅ 10 H2O per weigh, then prepare 100 ml 0.0250 M for dilution of the first.