Calcium carbonate reacts with phosphoric acid to produce calcium phosphate, carbon dioxide, and water.

Question

3 CaCO3(s) + 2 H3PO4(aq) Ca3(PO4)2(aq) + 3 CO2(g) + 3 H2O(l)

How many grams of phosphoric acid react with excess calcium carbonate to produce 3.47 g Ca3(PO4)2?

Answer 1

Here is a worked example of a stoichiometry problem similar to yours. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html