Separating Homogeneous Mixtures

Introduction A heterogeneous mixture is not uniform throughout. Therefore, separate components of a heterogeneous mixture can be separated by using differences in the components’ physical properties. In this laboratory experiment, I attempted to experimentally verify that the components of a heterogeneous mixture containing salt, sand, and benzoic acid can be separated using the separate components’ solubility properties (ability to dissolve in water). Because it is known that organic compounds (such as benzoic acid) are very soluble in organic solvents, a hexane: ethanol mixture was used to dissolve the acid. Also, because it is known that sodium chloride dissolves in water, water was used to dissolve the NaCl. Along with separating the components of a heterogeneous mixture, the percent recovery of each substance was calculated using the formula: % recovery = (final mass)/(inital mass) x 100. The percent recovery is the amount of substance that was recovered from before the experiment to after the experiment. Overall, in this laboratory experiment, differences in solubility could help to separate the difference components of a heterogeneous mixture of salt, sand, and benzoic acid.
Data
Benzoic Acid Trial 1
Mass of dry test tube 14.72 g
Mass of dry beaker 27.95 g
Mass of beaker with hexane: ethanol mixture and salt, sand 29.92 g
Volume of hexane: ethanol mixture 6 mL
Mass of benzoic acid (before) .18 g
Mass of beaker and benzoic acid crystals 28.10 g
Mass of benzoic acid (after) .15 g
% recovery of benzoic acid 83.3%

Salt Trial 1
Mass of dry test tube 14.72 g mass of dry beaker 28.23 g
Mass of salt (before) .18 g
Mass of beaker and salt (after) 28.46 g
Mass of salt (after) .23 g
% recovery of salt 127.7%

Sand Trial 1
Mass of dry test tube 14.72 g
Mass of sand (before) .22 g
Mass of test tube and sand (all water removed) 14.92 g
Mass of sand (after) .20 g
% recovery of sand 90.9%

Calculations
Sample percent recovery calculation: