Chemistry intro help

Question

For the chemical reaction, 

what mass of phosphoric acid in grams is needed to produce  of water?

Answer 1

Let' look at the equation:

3KOH+H3PO4⟶K3PO4+3H2O

It tells us that for every 1 mole of H3PO4, there will be three moles of H20, giving us a ration of 1 mole H3PO4/ 3 mole H20. Given the moleculaer weifht of H3PO4 is 98 grams per mole, we will use dimensional analysis to solve this problem:

5.37 mol H20 x 1 mol H3PO4/ 3 mol H20 x 98 grams H3PO4// mol H3PO4 = 175 grams H3PO4