Consider the following chemical equation.

Na3PO4(aq) + Ca(OH)2(aq) → Ca3(PO4)2(s) + NaOH(aq)
How many grams of calcium hydroxide must react to give 2.81 g of Ca3(PO4)2?

please explain step by step

1 answer

You first need to balance the equation.

This will give you the ratio of moles of Ca(OH)2 to Ca3(PO4)2.

calculate the molecular mass of
Ca(OH)2 (=Mp) and Ca3(PO4)2 (=Mo)

from the molecular mass (Mp) of Ca3(PO4)2 calculate the number of moles

number of moles = 2.81/Mp

using the ratio from the equation calculate the number of moles (Mo) of Ca(OH)2 needed to form the 2.81/Mp moles

the mass required is then

Mo x molecular mass of Ca(OH)2