Melting Point Experiment

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I. INTRODUCTION This report discusses an experiment, the objective of which was to determine the classification of six known chemicals: sodium nitrate, barium chloride, silicon carbide, naphthalene, urea, and antimony and two unknown chemicals XIa and XIb. Since each type of chemical (ionic, molecular, macromolecular and metallic) has its own set of properties, by testing these properties and finding them out for each chemical, it was possible to classify them. The properties tested during this experiment were solubility in water, toluene, and ethanol and the electrical resistance for those soluble in water. The melting point was tested for the two unknown chemicals. II. MATERIALS AND PROCEDURES List of chemicals used: Sodium nitrate,…show more content…
3) Distilled water was added to dissolve it. 4) The two electrodes were placed in the water while making sure that they were immersed in the solution but not touching each other or the surface of the beaker. 5) After about 10 seconds, the average of the readings were taken and recorded. III. RESULTS Substance Approx. Melting Point Solubility Water Non Polar Polar Electrical Resistance in Ohms Classification Sodium Nitrate Sol. Insol sol N Ionic Barium Chloride Sol. Insol. sol N Ionic Silicon Carbide Insol. Insol. Insol Macromolecular Napthalene Insol. Sol. Sol Molecular Urea Sol. Sol. Insol N Molecular Antimony Insol. Insol. Insol N Metallic XIa Not melted at 150°C Sol. Insol sol Ionic XIb Not melted at 150°C Insol. Insol. Insol Metallic IV.…show more content…
As mentioned in answer to question to 2b, ionic compounds have free mobile ions for conduction of electricity only in the molten state and in aqueous state. Hence, given substance is most likely to be ionic as it exhibits conductance only in these states. In addition to that, it has high melting point, which is characteristic of ionic compounds. [6] 4) A lustrous grey – white solid melts at 1650°C. It is electrically conductive as both a solid and a liquid, but not soluble in either water or any organic solvent. Classify the substance as best you can from these properties. Ans: Metallic. The high melting point rules out the molecular category due to the fact that molecular compounds have low melting point. [7] Conductivity in solid state leaves no doubt to the fact the substance is not ionic. And since it is lustrous, it must be metallic. (The reason why has been mentioned in the previous answers) V. REFERENCES (10 %) [4] Burrows, A.; Holman, J. S.; Parsons, A. F.; Pilling, G.; Price, G. Solids. In Chemistry 3: introducing inorganic, organic and physical chemistry, second; Oxford University Press: Oxford, 2013; pp

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