How many grams of dry NH4Cl need to be added to 2.30 L of a 0.500 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.99?

How many grams of dry NH4Cl need to be added to 2.30 L of a 0.500 M solution of ammonia, NH3, to prepare a buffer solution that has a pH of 8.99? kb for ammonia is 1.8*10^-5.