Final answer:
To determine which volumetric flask size to use for dissolving 60 g of NaOH, calculate the moles of NaOH and select a flask that corresponds to the desired molarity and final volume of the solution.
Step-by-step explanation:
When the instruction says to "weigh 60 g of solid NaOH and add to the ____ volumetric flask", it is referring to the use of a volumetric flask to prepare a solution. The blank should specify the size of the volumetric flask that should be used, which depends on the desired molarity (concentration) and volume of the NaOH solution. Volumetric flasks come in various sizes, such as 100 mL, 250 mL, 500 mL, 1 L, etc.
To decide which volumetric flask to use, one needs to know the final concentration and volume of the NaOH solution. With 60 g of NaOH, which has a molar mass of 40.00 g/mol, you can calculate the number of moles of NaOH (60 g / 40.00 g/mol = 1.5 mol). Then, depending on the desired molarity, you choose a volumetric flask that will provide the necessary volume once the solid NaOH is dissolved in water and the solution is diluted to the mark.
For example, a 1.00 M solution requires 1 mole of solute per liter of solution. Therefore, to prepare a 1.00 M NaOH solution using 60 g of NaOH (1.5 moles), you would need a 1.5 L volumetric flask. However, if the task requires a different molarity, you would select a volumetric flask accordingly. It is important to half-fill the flask with distilled water, add the weighed NaOH, dissolve it completely, and then fill to the mark of the volumetric flask to achieve the desired final volume.