This laboratory work was focused on determination of the relation between density and concentration of a salt solution. The density was measured for the standardized solutions and showed the direct linear dependence. The experimental equation is d=0.0065×C%+0.9785. It was used to determine the concentration of an unknown salt solution from its density.
Introduction
The density of any solution is a cartelistic. It represents the mass to volume correlation.
density=masswolume Equation 1
It is known to change with temperature and concentration, however, these changes cane minor and literally negligible. Still this dependence can be used to determine the concentration based on the density vs. concentration plots.
The salt solution has been investigated and they are known for the linear relation between concentration and density of salt solution. (Dugherty, 2001)
Experimental
General Methods and Materials. Materials used in this procedure were provided by the Fresno State Freshman Chemistry Stockroom. A laboratory balances have been used for measurements. MS Excel instruments were used to perform the statistical data manipulation and to determine the trend equation.
Procedure. The salt solutions were prepared at ambient temperature by dissolving salt in distilled water taken in definite ratios. The density determination was performed by weighting 10ml of the obtained solution. Series included three samples for each solution.
Results and Discussion
The arithmetic mean values has been determined assuming all data to be significant. The average density and concentration are listed inTable 1.
The relation between concentration and density of a salt solution trend is clear; the higher the concentration the higher the density.
The experimental data have been plotted (Figure 1) to visualize the standard curve and the linear trend line was drawn.
Figure 1 The relation between concentration and density of a slat solutions
The R-squared value is close to 1, so the line fits the data very good and the density vs. concentration equation is set as follows:
d=0.0065×C%+0.9785 Equation 2
These standard curve and equation were used to concentration for unknown salt solution based on its density.
The arithmetic mean density for the unknown solution is 1.029 g/ml. The concentration determined from the graph is 7.7% (Figure 2)
Figure 1 The concentration of the unknown solution.
The exact number was calculated using the equation 2.
C%=1.029-0.97850.0065=7.6923%≅7.7%
Comments and Conclusions
The experimental data has shown linear correlation between density and consentration of a salt solution. The corresponding equation has been calculated. This experimental equation has been to measure the concentration of an unknown solution.
Acknowledgment. The author thanks .
Supporting Information Available: The determined density for series of standard solution is listed in the supporting information section.
References
Dugherty, D.C. J. Phys. Chem. B, 2001, 105 (19), 4514–4519.
Supporting Information for Manuscript
