Final answer:
To determine the grams of NaOH needed to prepare 250 mL of a solution, the desired molarity must be known. Then, using the molarity and the molar mass of NaOH, the mass in grams can be calculated. Without the molarity, it is not possible to give an exact answer.
Step-by-step explanation:
The original question asks how many grams of NaOH are needed to make 250 mL of a solution, but it's important to note that the concentration of the solution is not provided. To accurately answer this question, we would need the desired molarity of the NaOH solution. In chemistry, if the molarity is known, the number of grams can be calculated using the formula:
mass (g) = molarity (M) × molar mass (NaOH, g/mol) × volume (L)
For example, if we were preparing a 1.0 M NaOH solution, we would dissolve 40.0 g of NaOH (molar mass of NaOH) in water to make 1 liter of solution. Since the question specifies a 250 mL solution, we would use one-fourth of that mass, which would be 10.0 g of NaOH.
Without the target molarity, we can't provide the exact mass of NaOH required. The mass of NaOH in the sample solutions provided in the reference information ranged from 3.5 g to 50.0 g, depending on the other parameters such as volume and molarity that were specified in those examples.