3.5 grams of Sodium Phosphate is mixed with 6.4 grams of Barium Nitrate. How many grams of Barium Phosphate will be produced?

Answer 1

I work these limiting reagent problems (you know it is limiting reagent when BOTH reactants are given) by working TWO simple stoichiometry problems. By simple I mean they are not limiting reagent problems. Here is a worked example of a simple stoichiometry problem. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html

By working two problems, one problem for each of the reactants, you will obtain two separate answers (different answers) for the amount of the product. The correct answer in limiting reagent problems is ALWAYS the smaller value and the reagent producing that value is the limiting reagent.
Post your work if you get stuck.