Use the Henderson-Hasselbalch equation to perform thefollowing calculations. The
ID: 682103 • Letter: U
Question
Use the Henderson-Hasselbalch equation to perform thefollowing calculations. The Ka of acetic acid is1.8*10-5. Buffer A: calculate the mass of solid sodium acetate requiredto mix with 100.0mL of 0.1M acetic acid to prepare a pH 4buffer Buffer B: Calculate the mass of solid sodium acetate requiredto miz with 100.0 mL of 1.0 M acetic acid to prepare a pH 4buffer. Use the Henderson-Hasselbalch equation to perform thefollowing calculations. The Ka of acetic acid is1.8*10-5. Buffer A: calculate the mass of solid sodium acetate requiredto mix with 100.0mL of 0.1M acetic acid to prepare a pH 4buffer Buffer B: Calculate the mass of solid sodium acetate requiredto miz with 100.0 mL of 1.0 M acetic acid to prepare a pH 4buffer.Explanation / Answer
Formula: pH = pKa + log ( No.of moles of salt / No.of moles ofacid) a) pH = 4 pKa= 4.74 ( For acetic acid) Number of moles of acid = 0.01 moles Upon substituting the data in the formula, 4 = 4.74 + log ( x / 0.01 ) log ( x / 0.1 ) = -0.74 x / 0.01 = 0.18 x = 0.0018 moles Molar mass of sodium acetate = 82.03 g / mol Mass of the salt= 82.03 g / mol * 0.0018 moles = 0.14766 g pKa= 4.74 ( For acetic acid) Number of moles of acid = 0.01 moles Upon substituting the data in the formula, 4 = 4.74 + log ( x / 0.01 ) log ( x / 0.1 ) = -0.74 x / 0.01 = 0.18 x = 0.0018 moles Molar mass of sodium acetate = 82.03 g / mol Mass of the salt= 82.03 g / mol * 0.0018 moles = 0.14766 g b ) pH = 4 pKa= 4.74 ( For acetic acid) Number of moles of acid = 0.1 moles Upon substituting the data in the formula, 4 = 4.74 + log ( x / 0.1 ) log ( x / 0.1 ) = -0.74 x / 0.1 =0.18 x = 0.018 moles Molar mass of sodium acetate = 82.03 g / mol Mass of the salt= 82.03 g / mol * 0.018 moles = 1.4766 gRelated Questions
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