1. What are the factors that affect the solubility of SDS
A presentation by: Lyndsey, Jordy and Jen

2. Research questions
How does the polarity of the solvent affect the solubility of the solute?
How does the temperature of the solvent affect the solubility of the solute?

3. Variables Dependent Variables Degree of solubility
Independent Variables Temperature Polarity of Solvent
Controlled Variables
Mass of Solute
Volume of Solvent
Sample Solute
Time

4. Sodium Dodecyl sulfate (SDS)
Non-Polar
Polar
Anionic surfactant
Amphiphilic
Lowers the surface tension of aqueous solutions
Used primarily in: soaps and detergents

5. The solvents Water Strongly Polar Solution Isopropyl Alcohol
Vegetable Oil
Non-Polar Solution

6. What is “soluble”? Dissociation of salt Lack of visible crystals
1g dissolves in 100mL

7. Method
100mL of solvent (water, isopropyl alcohol or vegetable oil) was measured into a 400 mL beaker that contained a stir bar
The solvent was cooled/heated to the desired temperature
1 g of SDS was added to the beaker
The solution was allowed to stir for 30s
After 30s the solution was examined to determine if there was a homogeneous mixture

8. Results Insoluble Soluble Temperature 4°C RT 40°C 70°C Water
Vegetable Oil
Isopropanol

9. observations: Water Temperature: 4°C Insoluble Room Temperature

10. observations: Water Temperature: 40°C Temperature: 70°C Soluble

11. observations: isopropyl alcohol
Temperature: 4°C
Soluble
Room Temperature
Soluble

12. observations: isopropyl alcohol
Temperature: 40°C
Soluble
Temperature: 70°C
Soluble

13. Observations: vegetable oil
Temperature: 4°C
Insoluble
Room Temperature
Insoluble

14. Observations: vegetable oil
Temperature: 40°C
Insoluble
Temperature: 70°C
Insoluble

15. Analysis: Common Trends
The solubility of SDS in a nonpolar solution was independent of the temperature of the solution
No clear trends were visible for polar solutions due to insufficient data
SDS is mostly soluble in polar solutions
SDS is insoluble in nonpolar solutions

16. Sources of error Errors associated with measurement
Inconsistent room temperature
Inconsistent stirring speed
Production of bubbles from surfactant
Influences the solubility determination

17. Improvements Require: Quantitative Analysis
Determine the maximum concentration of the solute able to dissolve in the solvent at the given temperature
Better regulation of temperature
Purity of Solvent
Investigation of Common Ion Effect by way of different solvents

18. Conclusion
SDS is soluble in polar solutions at a variety of temperatures
SDS is insoluble in nonpolar solutions
The structural properties of isopropyl alcohol contain polar and nonpolar ends allowing it to associate with the amphiphilic properties of SDS resulting in a lack of bubbles