Question

A 25 liter solution contains 205 grams of calcium hydroxide.

What is the molarity of hydroxide ions in the solution?

How many grams of calcium ions are in the solution?

Please show steps

Thank you for your time

Answer 1

volume of solⁿ=25L

given mass of Ca(OH)₂=205g

Molar mass of Ca(OH)₂=40.08+2(16+1.01)=40.08+34.02=74.10g/mol

no of moles of Ca(OH)₂=given mass/molar mass

=205/74.10

=2.76mol

Ca(OH)₂(aq)------->Ca²⁺(aq)+2OH^-
this means one mole of Ca(OH)₂ is equal to one mole of Ca ion and 2 moles of hydroxide ion

hence,

no of moles of OH^- in 205g of Ca(OH)₂=2(no of moles of Ca(OH)₂)

=5.52mol

molarity=moles of solute/volume of solⁿ

=5.52/25

=0.2208M

molar mass of Ca²⁺=40.08g/mol

no of moles of Ca²⁺=2.76mol

amount of Ca²⁺ present in solⁿ=molar mass*no of moles

=40.08*2.76

=110.62g