How would you make 450 mL of a 0.250 M NaOH solution?

To make a 0.250 M NaOH solution, you'll need to know the molar mass of NaOH and have access to a balance to measure the required mass. Here's how you can calculate and prepare the solution:

1. Find the molar mass of NaOH: The molar mass of sodium (Na) is 22.99 g/mol, the molar mass of oxygen (O) is 16.00 g/mol, and the molar mass of hydrogen (H) is 1.01 g/mol. Adding these together, we get the molar mass of NaOH as 22.99 + 16.00 + 1.01 = 40.00 g/mol.

2. Calculate the mass of NaOH needed: The formula for calculating the mass is given by mass = (concentration × volume × molar mass) / 1000. Rearrange the formula to solve for mass: mass = (concentration × volume × molar mass) / 1000. Plug in the given values: mass = (0.250 mol/L × 0.450 L × 40.00 g/mol) / 1000. Calculate the mass to obtain the quantity of NaOH needed.

3. Measure out the required mass of NaOH: Using a balance, measure the calculated mass of NaOH.

4. Dissolve NaOH in a container with some water: Add a small amount of distilled water to a container (preferably a beaker) and gradually add the measured mass of NaOH while stirring continuously. Use caution as the NaOH may release heat when mixed with water, so it's important to add it slowly and carefully.

5. Gradually add more water and mix: Once the NaOH is dissolved, slowly add more water to the container while stirring to reach the final volume of 450 mL.

6. Transfer to a final container: After reaching 450 mL, transfer the solution to a volumetric flask or any other suitable container. Ensure that the solution is mixed thoroughly.

Now, you have prepared 450 mL of a 0.250 M NaOH solution. Remember to handle NaOH with care and take necessary safety precautions, such as using gloves and goggles.