what are the factors that affect the solubility of sds a presentation by: lyndsey, jordy and jen
TRANSCRIPT
WHAT ARE THE FACTORS THAT
AFFECT THE SOLUBILITY OF
SDSA PRESENTATION BY: LYNDSEY, JORDY AND JEN
RESEARCH QUESTIONS
1. How does the polarity of the solvent affect the solubility of the solute?
2. How does the temperature of the solvent affect the solubility of the solute?
VARIABLES
Dependent Variables
Degree of solubility
Independent Variables
Temperature
Polarity of Solvent
Controlled Variables
Mass of Solute
Volume of Solvent
Sample Solute
Time
SODIUM DODECYL SULFATE (SDS)
Non-Polar Polar
• Anionic surfactant• Amphiphilic• Lowers the surface tension of aqueous
solutions• Used primarily in: soaps and detergents
THE SOLVENTS
1. Water
• Strongly Polar Solution
2. Isopropyl Alcohol
• Polar Solution
3. Vegetable Oil
• Non-Polar Solution
WHAT IS “SOLUBLE”?
• Dissociation of salt
• Lack of visible crystals
• 1g dissolves in 100mL
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
RESULTS
Temperature 4°C RT 40°C 70°C
Water Insoluble Soluble Soluble Soluble
Vegetable Oil Insoluble Insoluble Insoluble Insoluble
Isopropanol Soluble Soluble Soluble Soluble
OBSERVATIONS: WATER
Temperature: 4°CInsoluble
Room TemperatureSoluble
OBSERVATIONS: WATER
Temperature: 40°CSoluble
Temperature: 70°CSoluble
OBSERVATIONS: ISOPROPYL ALCOHOL
Temperature: 4°CSoluble
Room TemperatureSoluble
OBSERVATIONS: ISOPROPYL ALCOHOL
Temperature: 40°CSoluble
Temperature: 70°CSoluble
OBSERVATIONS: VEGETABLE OIL
Temperature: 4°CInsoluble
Room TemperatureInsoluble
OBSERVATIONS: VEGETABLE OIL
Temperature: 40°CInsoluble
Temperature: 70°CInsoluble
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
SOURCES OF ERROR
• Errors associated with measurement
• Inconsistent room temperature
• Inconsistent stirring speed
• Production of bubbles from surfactant
• Influences the solubility determination
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
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