Question

A student measures out 0.60g of Ca metal and adds it to 150 mL of deionized water. The student then titrates the solution with 109.10mL of 0.550M HCl. From this experimental data, what is the formula of calcium hydroxide produced from the reaction of Ca with water

Answer 1

Given : mass Ca = 0.60 g

moles Ca = (mass Ca) / (moles Ca)

moles Ca = (0.60 g) / (40.078 g/mol)

moles Ca = 0.0150 mol

Concentration HCl = 0.550 M

volume HCl = 109.10 mL = 109.10 x 10^-3 L

moles HCl = (Concentration HCl) * (volume HCl in Liter)

moles HCl = (0.550 M) * (109.10 x 10^-3 L)

moles HCl = 0.0600 mol

moles OH^- = moles HCl

moles OH^- = 0.0600 mol

moles OH^- / moles Ca²⁺ = (0.0600 mol) / (0.0150 mol)

moles OH^- / moles Ca²⁺ = 4

There are 4 OH^- ions per one ion of Ca

Formula of calcium hydroxide : Ca(OH)₄