Lab Report Identifying Unknown Substances by Characteristic Properties

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Lab Report Identifying Unknown Substances by Characteristic Properties Purpose: To identify the unknown substance by characteristic properties. Materials: * 30g white substance * thermometer * 40mL water * 4 evaporating dishes * stirring rod * balance * bunsen burner * graph paper * ring stand * pencil * safety goggles * 10mL graduated cylinder * beaker * 4 test tubes Procedure: 1.) Obtain your materials. 2.) Seperate your 40mL of water into 4 different test tubes, 10mL in each. 3.) Divide your 30g of white substance into the 4 test tubes evenly. You should put 7.5g into each test tube along with the water. 4.) Set up your apparatus as shown below: 5.) One at a time, place your test tubes in the water bath and heat the first test tube to 25 , the second to 50 , the third to 75, and the last to 100 degrees c. Remeber to stir with your stirring rod every so often. 6.) Mass your 4 dry evaporating dishes. 7.) After you have heated them to the right temperatures, pour the excess water into a dry evaporating dish. ( Be sure not to get any of the substance in your solution. ) 8.) Boil off the water, using the same apparatus as in step 4. 9.) Repeat steps 7 and 8 for the other 3 test tubes. 10.) Mass the evaporating dish and it's contents. 11.) Subtract the mass of the evaporating dish from the mass of the evaporating dish and it's contents. Multiply that number by 10 to get the solubilty in grams per 100 cm3 of water. 12.) Plot your graph and use the curve to identify what substance you had. Data Analysis: Temp: Mass of evap. dish: Mass of evap dish+contents: Mass of contents: Solubility g/100cm3 water 25c 67.75g 69.69g 1.95g 19.5g 50c 65.31g 68.92g 3.

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