Final answer:
To prepare 125 mL of a 0.100 M NaNO3 solution, calculate the mass of NaNO3 required, dissolve it in a volumetric flask with less than 125 mL of water, then dilute to the mark to ensure the correct final volume.
Step-by-step explanation:
Preparing a 0.100 M NaNO3 Solution
To prepare 125 mL of a 0.100 M NaNO3 solution from a dry solute, you need to calculate the amount of NaNO3 required for the desired molar concentration in the given volume of solvent (water). First, calculate the moles of NaNO3 needed using the formula: moles = molarity × volume (in liters). This gives you 0.100 moles/L × 0.125 L = 0.0125 moles. Next, calculate the mass of NaNO3 needed by multiplying the moles by the molar mass of NaNO3 (85.00 g/mol). This yields 0.0125 moles × 85.00 g/mol = 1.0625 g of NaNO3.
Then, weigh 1.0625 g of NaNO3 using a balance, and add it to a volumetric flask. Add a small amount of distilled water to dissolve the NaNO3, swirling gently. Once dissolved, add more distilled water until the bottom of the meniscus touches the 125 mL mark of the flask. Ensure the final volume is exactly 125 mL; the solute takes up some space, so you will add less than 125 mL of water to achieve the desired final solution volume.
Finally, put the stopper on the volumetric flask and invert it several times to ensure thorough mixing of the NaNO3 solution. The solution is now ready for use in your experiment or procedure.