The crystals will then be collected using vacuum filtration and a Buchner funnel. The mixture will be heated in a hot sand bath until the solvent begins to boil. The mixture will then be brought to a boil and boiled gently for one to two minutes. Then the weights and melting points of the purified and impure samples will be determined using a Mel-Temp apparatus.
The second trial resulted in a melting point of When mixed with the water, the water turned a bright transparent blue color. This mixture was then heated in the Erlenmeyer flask on a hot plate until the acetanilide dissolved. The mixture is to be heated until the acetanilide dissolves.
About an additional 0. Transparent rectangular shaped crystals were collected in the filter paper. Two melting point capillaries with samples of pure naphthalene will be tested with a Mel-Temp device to determine their melting point.
The mL Erlenmeyer flask with the mixture is then to be cooled in an ice bath. The solution should then be filtered through a fluted filter into a warmed mL Erlenmeyer flask.
The crystals recovered weighed 0. The remainder will be weighed and placed into a mL Erlenmeyer flask with 50 mL of water and several boiling stones. The crystals were yellow, thin, and long. Of that sample, 0. Once it is room temperature, the Craig tube will cool in an ice bath and then placed in a centrifuge to collect the crystals.
Sample Weight Impure Acetanilide g 2. For the second part of the experiment, a sample of pure naphthalene was obtained and loaded into two cappillaries to determine its melting point using a Mel-Temp device.
This flask was then put into an ice bath to cool for about 5 minutes.
It was covered in sand up to the level of solution present and it was heated until the solvent began to boil. The Craig tube was then removed from the heat and was allowed to cool for about five mintues at room temperature and then another few mintues in an ice water bath.
For the third part of the experiment, a 0. As the mixture was filtered, crystals began to form in the filtrate in the mL Erlenmeyer flask.
The crystals are then to air-dry on a watch glass for several days.The melting point ranges was compared to the melting points of compounds found in Table Melting Point Standards and Table Melting Point Unknowns in the text. It should be noted that while the procedure suggests using compounds listed in Table Melting Point Standards, the compound evaluated in lab was benzophenone.
Another, less well-known reaction to produce benzophenone is the pyrolysis of anhydrous calcium benzoate. Organic chemistry.
Benzophenone is a common photosensitizer in photochemistry. It crosses from the S 1 state into the triplet state with nearly % yield.
The melting point is the temperature at which a substance changes state from solid to liquid at atmospheric pressure. When considered as the temperature of the reverse change, from liquid to solid, it is referred to as the freezing point.
MELTING POINT DETERMINATION PURPOSE Identify an unknown compound by its melting point. MATERIALS •Mel-Temp melting point apparatus •capillary tube •unknown sample •Table of Melting Point Data •laboratory notebook THEORY The melting point (mp) of a substance is one of the physical properties that chemists use to identify a.
Sources of error: 1, impure substance. The impurities will increase the boiling point. The impurities will increase the boiling point.
Also the impurities always decrease the melting point of a compound.
2, record the temperature too late during the melting point %(2). EXPERIMENT 1 (Organic Chemistry I) Melting Point Determination. Purpose. a) Determine the purity of a substance using melting point as physical property. b) Identify an unknown compound using its melting point.
c) Identify an unknown compound using mixture melting point. d) Benzophenone D. Determination of the .Download