How much of each component would you need to make a 0.5 M sodium phosphate buffer containing 0.5 M KCl and 0.05% sodium azide, pH 8.0?
At first you need to prepare stock solutions of 1M NaH2PO4 and 1M of Na2HPO4. Dissolve 138 g of NaH2PO4•H2O in H2O to final volume 1L. Dissolve 142 g of Na2HPO4 in water to final volume 1L. Than mix 466 mL of 1M NaH2PO4 and 34 mL of 1M Na2HPO4. Add 37 g of KCl, dissolve it. Add 0.5 g of sodium azide. Additionally check PH. Add H2O to 1L.