21-3 CHEMISTRY HELP PLEASE

Question

The following chemical equation has NOT been balanced.

 

H₃PO₄ + Ca(OH)₂ --> Ca₃(PO₄)₂ + H₂O

 

How many grams of calcium hydroxide are needed to produce 17.94 grams of water?

Answer value

Answer 1

2H₃PO₄ + 3Ca(OH)₂ ==> Ca₃(PO₄)₂ + 6H₂O ... balanced equation

molar mass H2O = 18 g/mol

molar mass Ca(OH)₂ = 74.09 g/mol

Using dimensional analysis...

17.94 g H₂O x 1 mol H₂O/18 g x 3 mol Ca(OH)₂ / 6 mol H₂O x 74.09 g Ca(OH)₂/mol = 36.92 g Ca(OH)₂