To calculate the percent composition by mass of the solution, we need to first determine the total mass of the solution. This can be calculated by adding the mass of the solute (5.57g SrCl2) to the mass of the solvent (95g water):
Total mass of solution = 5.57g + 95g = 100.57g
Next, we need to determine the mass percent of the solute in the solution. This can be calculated using the following formula:
Mass percent of solute = (mass of solute / total mass of solution) x 100%
Plugging in the values we have:
Mass percent of SrCl2 = (5.57g / 100.57g) x 100% = 5.53%
Therefore, the percent composition by mass of the solution prepared by dissolving 5.57g of SrCl2 in 95g of water is 5.53% SrCl2 and 94.47% water.