16 solubility

General Chemistry LaboratoryUniversity of Kentucky

Solubility of Calcium Hydroxide

Preparation

Write the procedure for the experimentProcedure should contain enough

detail so someone else could replicate it without additional information

Determine the approximate mass of Ca(OH)2 to use for your saturated solution

Both must be done before you come to class

Experiment

Three partsPreparing saturated solutionStandardization of HClDetermine [OH¯]

Saturated Solution

Prepare saturated solution on Day 1 Save for Day 2 to complete titrations

Standardization of HCl

Record exact mass of Na2CO3 used for each trial

Do not refill HCl bottle during experiment

Save HCl solution for next week’s lab

Titration: HCl and Ca(OH)2

Filter Ca(OH)2 before using Titration will have two equivalence

points; sometimes only one will show

Ksp

Review solubility and Ksp in your textbookSetting up a Ksp expression

Calculations involving Ksp

Experiment Tips

Need three good titrations for each part

Titration curves may only show one equivalence point even though there are twoFirst one is sometimes hard to seeContinue until data plateaus

Experiment Tips

Record exact volumes used for all masses and volumes

When using buret, estimate the second decimal place

Mix after every addition to get accurate pH values