What masses of sodium chloride and water do you need to take to prepare 500 g of 0.9 solution?

The mass of the solution is 500 grams;

To find the mass of salt, it is necessary to multiply its mass fraction by the mass of the solution.

m of salt = 500 x 0.9% = 500 x 0.9 / 100 = 4.5 grams;

To find the mass of water, subtract the mass of salt from the mass of the solution:

m of water = 500 – 4.5 = 495.5 grams;

Check: 495.5 + 4.5 = 500;