Final answer:
To find the volume of a 25% NaF solution containing 4.0 g of NaF, calculate the molarity using molar mass and density, then use the molarity to determine the volume in milliliters.
Step-by-step explanation:
To calculate the volume of solution that contains 4.0 g of NaF when the concentration is 25%, we need to first find the molarity of the solution. This involves understanding the molar mass of NaF and the density of the solution.
Steps to Find the Molarity:
- Determine the molar mass of NaF, which is 41.99 g/mol.
- Because the solution has a density of 1.02 g/mL, calculate the mass in one liter (1000mL) of the solution. This would be 1020 g since density is mass per unit volume (1.02 g/mL * 1000 mL/L).
- Find how many grams of NaF would be in 1020 g of the 25% solution. This would be 25% of 1020 g, which is 255 g of NaF.
- Now, convert the amount of NaF to moles using its molar mass (255 g / 41.99 g/mol).
Once we have the number of moles, we can calculate the volume of solution needed by comparing it to the 4.0 g of NaF the problem requests. Finally, you'll be able to determine the volume in milliliters needed to obtain 4.0 g of NaF from the 25% solution.