It seems like you're asking about making a 5% (w/v) sodium chloride solution. Here's how to calculate the amount of NaCl needed:

Understanding the terms:

* 5% (w/v): This means 5 grams of NaCl per 100 mL of solution.

* 500 mL final volume: This is the total volume of the solution you want to make.

Calculation:

1. Calculate the mass of NaCl needed:

* Since 5% (w/v) means 5 grams of NaCl per 100 mL of solution, for 500 mL you need 5 times that amount.

* Mass of NaCl = (5 g/100 mL) * 500 mL = 25 grams

Answer: You would dissolve 25 grams of sodium chloride in water to make a 5% (w/v) solution with a final volume of 500 mL.