Chemistry
posted by Lee on .
How many grams of Ca3(PO4)2 can be formed from 206 g of calcium nitrate and 140 g of phosphoric acid?

A limiting reagent problem. I know that because amounts are given for BOTH reactants.
1. Write the equation and balance it.
2a. Convert grams Ca(NO3)2 to mols.
mols = grams/molar mass.
2b. Do the same for H3PO4.
3a. Using the coefficients in the balanced equation, convert mols Ca(NO3)2 to mol Ca3(POO4)2.
3b. Do the same for mols H3PO4.
3c. It is likely the two values in 3a and 3b will be agree which means one of them must be wrong. The correct value in limiting reagent problems is ALWAYS the smaller value and the reagent producing that value is the limiting reagent.
4. Using the smaller value convert to grams Ca3(PO4)2. g = mols x molar mass. 
How do you balance the equation when you have calcium nitrate and phosphoric acid?

3Ca(NO3)2 + 2H3PO4=>Ca3(PO4)2 + 6HNO3

Thanks!