ADDITIONAL PRACTICE PROBLEMS

How many grams of acetic acid and how many ml of 1 M NaOH are needed to make 1 liter of 50 mM acetate buffer, pH 5.0? The pKa of acetate is 4.76 and molecular weight of acetic acid is 60.

3 g of acetic acid and 32 ml of 1 M NaOH

How many grams of HEPES and how many mls of 1 M NaOH are needed to prepare 1 liter of a 0.1 M HEPES buffer at pH 7.4? The pKa of HEPES is 7.5 and the molecular weight is 238.

23.8 g HEPES and 44 ml of 1 M NaOH

How many grams of Tris and TrisHCl are needed to make up 1 liter of 0.5 M Tris buffer at pH 8.8? The pKa of Tris is 8.3 and the molecular weights of Tris and TrisHCl are 121 and 157, respectively.

46 g of Tris and 18.9 g of TrisHCl

How many grams of MES (mol. wt. = 195) and the Na+ salt of MES (mol. wt = 212) are needed to make 100 ml of 0.5 M MES at pH 6.0? (pKa of MES = 6.15)

5.7 g of MES and 4.5 g of NaMES

How many grams of tricine (mol. wt. = 179) and how many ml of 1 N HCl are needed to make up 200 ml of 0.1 M tricine Buffer at pH 8.5? (pKa of tricine = 8.15)

3.6 g of tricine and 6.2 ml of 1 N HCl

[Note: the answers were not double-checked. Hopefully there are no errors.]