1. Preparing Solutions LG: I can use formulas for concentration to prepare standard solutions from a solid

2. Practice Calculation What mass of solid sodium hydroxide would be required to prepare 100 mL of 0.500 mol/L solution?

3. Standard Solutions Solutions with precisely known concentrations are called standard solutions. – Measurements are only as accurate as your equipment! Standard solutions can be prepared by dissolving a solid solute in a solvent, OR By diluting a more concentrated solution

4. Activity 1: Preparing a Standard Solution from a Solid Calculate the mass of solid required to prepare specified volume of solution Measure the required mass in a clean, dry, 50 mL beaker Dissolve the solid in ~40 mL of pure water Transfer the solution to a volumetric flask (100 or 250 mL) Rinse the beaker 2 or 3 times with small amounts of pure water and add the rinsings to the flask Add pure water to the flask until the volume is 100.0 mL Stopper the flask and seal with Parafilm, then mix by inverting repeatedly

5. Preparing Solutions LG: I can use formulas for concentration to prepare standard solutions by dilution

6. Practice Calculation You need 100 mL of 0.200 mol/L hydrochloric acid. The only solution available is 1.5 mol/L. What volume of the more concentrated acid will you require?

7. Activity 2: Preparing a Standard Solution by Dilution Calculate the volume of 0.500 mol/L standard solution required to prepare 100 mL of 0.100 mol/L solution. Add 40-50 mL of pure water to a 100 mL volumetric flask. Measure the required volume of standard solution using a 10 mL pipet and transfer to the 100 mL flask Add pure water until the final volume is reached Stopper the flask and mix thoroughly by inverting