Chem still confused
posted by Jon on .
1.) A biochemistry student wants to make 4 liters of a phosphate solution using 48.6 g Na2HPO4 (FW=141.96) What is the concentration of this solution?
2. When she reaches the storeroom she finds that there is no Na2HPO4, however there is a bottle of hydrate Na2HPO4 * 7H20. (FW=268.07) how many grams of this salt should she use in order to make 4 liters with the same phosphate concentration as above?

I thought I worked this once. And you want me to go through it again? I'll be glad to help bur this could go on forever. Please post my response and show your work. Explain fully at which step you get stuck and we can go from there.