Overview
Objective
Laboratory Equipment and Procedure
Densitometer
Pycnometer
Results
Conclusions and Recommendations
Questions
Objective
Identify the density of an unknown salt solution using two different methods
Densitometry
Pycnometry
Determine which method is most accurate
Equipment – Densitometer
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.
Equipment – Densitometer (cont.)
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

A 2 molar solution was run for calibration purposes
Equipment – Pycnometer
Pycnometers utilize the basic equation for density
ρ = mass/volume

The volume is known and the mass is weighed on a scale

Results – Densitometer
Results – Pycnometer
Results Comparison
Densitometer results (95% CI)
ρ = 1.0002 +/- 0.0004 g/cm3

Pycnometer results (95% CI)
ρ = 1.0008 +/- 0.014 g/cm3
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

References and Acknowledgements
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

Thanks to my lab partner Randy Pummill
Questions?

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