Hi Katie, it looks like you are trying to calculate the grams of NaCl (sodium chloride) in 1.6L of a 0.5% solution. There are two possible ways to answer this question.

The formula for mass percent solutions is as follows:

percent solution = 100 * (grams of solute / grams of solvent)

1mL of water = 1 gram, and so the total mass of your solvent would be: