Final answer:
To calculate the mass percent of NaCl in the diluted solution, the mass of NaCl in the initial 75 grams of solution must be known. Without this information, we cannot accurately determine the new concentration after adding 500 grams of water.
Step-by-step explanation:
To find the mass percent of NaCl in the diluted solution after adding 500 grams of water to 75 grams of a NaCl solution, we need to first understand that the mass percent is the mass of the solute (NaCl) divided by the total mass of the solution (water + NaCl solution) and then multiplied by 100 to get the percentage.
The question does not specify the mass of NaCl already present in the 75 grams of NaCl solution, therefore we need to make an assumption or have that information provided to proceed with the calculation.
If we assume that the initial 75 grams of solution is pure NaCl (which is unlikely, but without any other information provided we cannot proceed), the calculation would be as follows:
Mass percent = (mass of NaCl / (mass of water + mass of NaCl solution)) x 100%
Mass percent = (75 g / (500 g + 75 g)) x 100%
= (75 g / 575 g) x 100%
= 13.04%
However, it is critical to know the concentration of the NaCl present in the initial 75 grams of solution to make an accurate calculation.