Identification of Compounds Using Physical Properties

Introduction In this experiment we will use physical properties to identify unknown substances Solubility of a solid in water, acid, base, organic solvent Density of a solid (volume by displacement) Melting Point

The Experiment You and your partner will receive 3g of one of the solid compounds on the list to identify by measuring solubility, density and melting point An unknown liquid that is on table 2 and you must identify it from its boiling point, density and solubility

Solubility of the Unknown Solid Solubility in: water acetone cyclohexane isopropanol Few crystals in a spot plate well with solvent Water and isopropanol are polar solvents (dissolve inorganic salts) Acetone, and cyclohexane are non-polar and will generally dissolve organic solids

Melting Point of the Unknown Solid few crystals  capilliary tube attach rubber band to a thermometer Immerse the thermometer/capilliary into a water bath as shown in the figure begin heating record the temperature at which the solid starts to melt

Density of the Unknown Solid Choose a liquid that your unknown is insoluble in Place V1=5.0 mL of this liquid in your 10 mL cylinder Weigh out and add M = 2 g (measure to 4 decimal places) to the cylinder and record the new volume V2

Solubility of an Unknown Liquid You will measure the solubility of an unknown liquid in acetone water cyclohexane isopropanol In four test tubes add 1 mL of your unknown and an equal amount of one of the solvents Record your observations

Boiling Point of the Unknown Liquid Construct the apparatus below, and record the temperature when small bubbles start to form in the test tube

Density of the Unknown Liquid Measure the mass of a small beaker M1 pipette 10.00 mL of your unknown liquid into the beaker and reweigh it M2