Mass or weight percent is the percentage of a given element or compound within a solution.
Example #1: Calculate the amount of water (in kilograms) that must be added to 12.0 g of urea, (NH2)2CO, in the preparation of a 18.3 percent by mass solution. The molar mass of urea, (NH2)2CO, is 60.055 g/mol.
A solution was prepared by dissolving 51.0 g of KBr in 310 mL of water. Calculate the mass percent of KBr in the solution.
Practice: At 298 K, a solution is prepared by dissolving 12.7 g NaCl in 95.5 mL of water. What is the ppm of NaCl if the density of water at this temperature is 0.9983 g/mL.