1. Liquid Density Analysis By Amanda Stiff CH EN 4903 November 22, 2006

2. Overview Objective Objective Laboratory Equipment and Procedure Laboratory Equipment and Procedure –Densitometer –Pycnometer Results Results Conclusions and Recommendations Conclusions and Recommendations Questions Questions

3. Objective Identify the density of an unknown salt solution using two different methods Identify the density of an unknown salt solution using two different methods  Densitometry  Pycnometry Determine which method is most accurate Determine which method is most accurate

4. Equipment - Densitometer Natural frequency or period (T) of a hollow U-tube is measured to determine the density of a liquid or gas Natural frequency or period (T) of a hollow U-tube is measured to determine the density of a liquid or gas Constants A and B in the equation are solved using density for water and air. Constants A and B in the equation are solved using density for water and air.

5. Equipment - Densitometer (cont.) The unknown liquid was injected into the densitometer and the period (T) was read from the display The unknown liquid was injected into the densitometer and the period (T) was read from the display Using the equation for the densitometer the density of the liquid is found Using the equation for the densitometer the density of the liquid is found A 2 molar solution was run for calibration purposes A 2 molar solution was run for calibration purposes

6. Equipment - Pycnometer Pycnometers utilize the basic equation for density Pycnometers utilize the basic equation for density  ρ = mass/volume The volume is known The volume is known and the mass is weighed and the mass is weighed on a scale on a scale

7. Results - Densitometer Densitometer @ 25.2 o CConstants A = 0.0706 B = 18.3721 AirWater2 MolarUnknown Period (T)4.28845.70235.79485.7046 4.28845.70225.79465.7047 4.28845.70215.79475.7047 Average (T)4.28845.70225.79475.7047 Density (g/cm 3 )0.00130.99821.07331.0002

8. Results - Pycnometer Pycnometer (10 ml) Empty Water (70 o F)2 MolarUnknown Average Weight (g)11.781521.913722.693521.9400 Average - Empty (g) 10.132210.912010.1585 Density (g/cm 3) 1.01321.09121.0159 Density via SG (g/cm 3 )0.99821.07501.0008

9. Results Comparison Densitometer results (95% CI) Densitometer results (95% CI)  ρ = 1.0002 +/- 0.0004 g/cm 3 Pycnometer results (95% CI) Pycnometer results (95% CI)  ρ = 1.0008 +/- 0.014 g/cm 3

10. Conclusions and Recommendations Densitometer was the more accurate method Pycnometry is a much easier method Know what kind of liquid you put into the densitometer Happy Thanksgiving

11. References and Acknowledgements CRC Handbook of Chemistry and Physics. 48th ed. Ohio: Chemical Rubber Co., 1967-68 CRC Handbook of Chemistry and Physics. 48th ed. Ohio: Chemical Rubber Co., 1967-68 National Institute of Standards and Technology. Retrieved August 30, 2006, from www.nist.gov/srd/pdf%20files/jpcrd196.pdf, Page 29 National Institute of Standards and Technology. Retrieved August 30, 2006, from www.nist.gov/srd/pdf%20files/jpcrd196.pdf, Page 29 Thanks to my lab partner Randy Pummill Thanks to my lab partner Randy Pummill

12. Questions?