How many moles of Ca3(PO4)2 would be formed from 40 grams of Ca in the following (UNBALANCED) equation?

Question

Ca + H3PO4 → Ca3(PO4)2 + H2

I believe that the balanced equation is:

3 Ca + 2 H3PO4 → Ca3(PO4)2 + 3 H2

But I am not sure where to go from there to find the answer.....

Answer 1

Convert the 3Ca to moles.  Then use the molar ratio of 3Ca to Ca3(PO4)2.

Answer 2

Balanced equation is right

moles of Ca = mass of calcium / Atomic Weight of Ca

=40/40

=1

As 3 moles of Ca will form 1 mole of Ca3(PO4)2 (from balanced equation), 1 mole of Ca will form 1/3 of Ca3(PO4)2 or 0.33 moles