Question

You are asked to prepare 500 mL 0.300 M acetate buffer at pH 4.90 using only pure acetic acid (MW = 60.05 g/mol pk, = 4.76), 3.00 M NaOH, and water. How many grams of acetic acid will be needed to prepare the 500 mL buffer? Note that the given concentration of acetate refers to the concentration of all acetate species in solution. mass: What volume of 3.00 M NaOH, must be added to the acetic acid to achieve a buffer with a pH of 4.90 at a final volume of 500. mL? Ignore activity coefficients, volume: mL Pour the beaker contents into a 500 mL volumetric flask. Rinse the beaker several times and add the rinses to the flask. Swirl the flask to mix the solution. Add water to the mark to make the times to ensure complete mixing? 01 02 20 O

Answer 1

Initial moles of CH3COOH =. Molanity x volume = 0.300 x 5007103 DUVCHD 0:15 mol Mass Ass of CH3 COOH = moles x molass mass šo iš molx.60.059mol. *900g to let à is the volume of NQOmis siis Moie of naoh = ax 3 1000 -0.003 a mol. cHg cool + NaOH -> Cl2 COONa + H2O, noles of CH36001 bbt = 0.15-0.003a mol Moles of CHa coona = moles of NaOH = 0.003a mo. we know that, Pit = Pka +109 Cuzcoonia) о сніз соон) 4,90 = 4.76 +109 0.0039 0.15-0.0030 109 0.0032 0.15-0.0030 = 0.14 IV 0.003a 0.15-0.0032

S o . 003 a. 2 11380, so 0.15-0.0030 . 0.0039 = 0.207-0.00414 Q 20.00714 a =0.207 p a z 28.99. volume Of NaOH = 28.99 m2: → vie 2 times it is the