Welcome to this spoken tutorial on Determination of Solubility Product using Vlabs.
In this tutorial we will learn to, Determine Solubility of salts and Calculate Solubility Product of various sparingly soluble salts.
Here, I am using Mac OS version 10.10.5
ChemCollective Vlabs version 2.1.0 and Java version 8.0
To follow this tutorial you should be familiar with, Chemcollective vlabs interface.
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Here, I have opened Virtual Chemistry labs application window.
Click on File menu and select Load Homework option. Default Lab Setup dialog-box opens.
Double-click on Solubility and Solids option. From the sub-menu, double-click on Determining the solubility product option.
A workbench opens with required chemicals and Problem Description.
Under the Stockroom Explorer double click on Problem Description.
Problem Description window opens.
The problem states that, using Virtual labs, We have to determine Solubility Products of Silver chloride Strontium Sulphate Silver Carbonate and Strontium Iodate.
We have to also find the solubility of the above salts in Moles/Litre.
Finally we have to compare the Solubility and Solubility Products for pairs of salts.
Close the Problem Description window.
A substance's solubility product, is the mathematical product of its dissolved ion concentrations raised to the power of their stoichiometric coefficients.
For Example: Solubility of Silver Chloride in its saturated solution is given as follows:
For every one mole of silver chloride that dissolves, one mole of silver ion and one mole of chloride ion is produced.
Let us assign a variable S to represent solubility of Silver and Chloride ions.
Solubility Product of silver chloride is S squared.
Here is the solubility of Silver carbonate in its saturated solution.
Stoichiometric concentrations of the ions are in the ratio of 2 : 1
In this equation, solubility of silver ion is two S and carbonate ion is S.
Solubility Product of silver carbonate is four S cube.
Significance of Solubility Product. Solubility Product applies to solutions where salts do not fully dissolve.
Water is generally used as a solvent. Solubility Product changes with temperature.
Solubility Product is a heterogeneous equilibrium constant.
The smaller the Solubility Product of a substance, the lower is its solubility.
Solubility Product values are useful in predicting, the precipitation in reactions.
When the Ionic product is greater than Solubility Product, then precipitation will occur.
When the Ionic product is smaller than Solubility Product, then precipitation will not occur.
Back to the workbench. From the Stockroom Explorer, double-click to select, Silver chloride Silver Carbonate Strontium Sulphate and Strontium Iodate.
Click on Select tools icon. Click to select Scale and Weighing Boat.
For this demonstration we require 4 copies of Weighing Boats.
Right-click on the Weighing Boat. Select Duplicate option from the context menu.
A new Weighing Boat appears. Similarly obtain other Weighing Boats.
Rearrange the Weighing Boats on the workbench.
Let us assign names to each one of them. Right-click on the Weighing Boat.
Select Rename option from the context menu.
Rename the Weighing Boats as 1, 2, 3 and 4.
From the Stockroom Explorer, double-click on 100 mL Distilled water flask.
100 mL Distilled water flask appears on the workbench. Right-click on the flask.
Use Duplicate option to make 4 copies.
Rearrange 100 mL Distilled water flasks on the workbench.
Right-click on the flask, select Rename option from the context menu. Rename the flasks as 1, 2, 3 and 4.
Bring the Scale to a convenient position on the workbench.
Place Weighing Boat 1 on the scale. Click TARE.
Weigh 5 grams of Silver Chloride. Bring the Silver Chloride bottle near to the Weighing Boat 1.
In the Transfer amount input bar , type 5. Click on Pour.
Keep the Silver Chloride bottle aside. Now let us transfer Silver Chloride to flask 1.
Bring Weighing Boat 1 to flask 1.
Type 5 in the Transfer amount input bar. Click on Pour. Keep Weighing Boat aside.
Click on Flask 1. Observe the Solution Info Panel.
By default Aqueous radio button is selected.
Concentrations of all the ionic species present in the solution are given here.
Click on the small black arrow, next to Molarity.
Here we can express concentrations in grams, moles and Molarity.
Note the concentrations of Silver ion and Chloride ion in terms of Molarity.
Similarly, using weighing boat, weigh 5 gm each of, Silver Carbonate Strontium Sulphate, and Strontium Iodate
Pour into flasks 2, 3 and 4 respectively.
Click on each flask. Wait till equilibrium is reached.
Note the concentrations of ions at equilibrium.
This value is the Solubility of that ion in its saturated solution.
Note solubility values for each ion in the table as shown here.
Calculate Solubility product for each salt. Note in the table.
Solubility products values for Strontium salts are more when compared to silver salts.
This is because Strontium salts are more soluble in water when compared to silver salts.
The experimental values of Solubility Product are comparable with known values.
Let us summarize. In this tutorial we have, Determined solubility of salts.
Calculated Solubility Product of various sparingly soluble salts.
As an assignment, For Strontium Sulphate and Strontium Iodate: Write dissociation equation and Solubility Product expression.
Find Solubility Product of these salts at 35° C.
Observe whether dissolution of these salts is exothermic or endothermic.
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This tutorial is contributed by Snehalatha Kaliappan and Madhuri Ganapathi from IIT-Bombay. Thank you for joining.