Purpose
Measure the melting points of pure benzoic acid and pure mandelic acid. Determine the eutectic composition and eutectic temperature of benzoic acid-mandelic acid mixtures. Indentify an unknown compound using mixture melting points.
Introduction
Energy is needed to be applied to a solid compound in order to changes its state point of a compound. The actual purpose of the experiment is to determine the measurement and the melting points of the benzoic and mandelic acid and various mixtures of mandalic and benzoic acid, and an unknown compound. In addition to that, later we will be able to indentify the unknown compound by comparing the melting points with the various compounds.
Materials needed to do the experiment
1. Bucket of Ice
2. Benzoic acid
3. Capillary tube
4. Mandelic acid
5. Rubber band
6. Vegetable oil
7. Unknown compound
8. Bunsen burner
9. Gram scale
10. Mortar and a piston
11. Mixture of benzoic and Mandelic acid
12. Micro-spatula
13. Thiele tube
14. Thermometer
15. Watch-glass
Procedure
The melting point will be observed with the use of a Thiele tube melting point apparatus. Primarily, using a mortar and its piston, the benzoic acid is ground (crushed) into fined powder. Two milligrams of it is measured and placed into a watch glass by which grams scale. From that point, a capillary tube is loaded with the fine powder by tapping the open end of the tube into the glass plate which the powder is located. Therefore, locate the powder at the bottom tube by tapping the closed and of the tube on the table top.