Question

Molar Solubility and Solubility Product of Calcium Hydroxide Volume of saturated Ca(OH)2 solution (mL) 25.00 Molar concentration of standard HCI solution (mol/L.) 0.0480 Buret reading, initial (mL) 1.70 Buret reading, final (mL) 13.90 Volume of HCI added (mL) Moles of HCI added (mol) Show calculation Moles of OH^- in saturated solution (mol) Show calculation [OH^-), equilibrium (mol/L) Show calculation. [Ca^2+], equilibrium (mol/L) Show calculation. Molar solubility of Ca(OH)2 (mol/L) Show calculation. Ks rho of Ca(OH)2 Show calculation. For Trials 2 and 3. the Ks rho of Ca(OH)2 was. 5.2 X 10^-6 and 4.8 times 10^6 respectively. What is the average of Ks rho Ca(OH)2? What are the standard deviation and the relative standard deviation(%RSD) for the Ks rho of Ca(OH)2? Molor Solubility, Common-ion Effect

Answer 1

Answer 2

Determine moles of HCl used:

moles HCl = (0.0480 mol / L) (0.0122 L) = 0.0005856 mol

2) Determine moles Ca(OH)₂ titrated:

0.0005856 mol / 2 = 0.0002928 mol

Remember, every one Ca(OH)₂ titrated requires 2 H⁺

3) Convert moles Ca(OH)₂ to grams Ca(OH)₂:

0.0002928 mol times 74.0918 g/mol = 0.02169 g

This is grams per 25.0 mL

3) Convert to grams per liter:

0.02169 g / 0.0250 L = 0.8676 g/L

1) 0.0002928 mol of Ca(OH)₂ in 25.0 mL means:

[Ca²⁺] = 0.0002928 mol / 0.0250 L = 0.011712 M
[OH¯] = 0.002342 M times 2 = 0.023424 M

2) Calculate the K_sp:

K_sp = (0.011712) (0.023424 )² = 6.4x 10¯⁵