AP Chemistry: Analysis Of Alum
AP Chemistry
Analysis of Alum
* Purpose: * In this lab we performed several tests to determine if our crystals were actually aluminum potassium sulfate. * Procedures: * Materials: * Chemicals: * Aluminum potassium sulfate, 2.5 g * Equipment – Part 1: * 150 mL beaker * Bunsen burner * 2 capillary tubes * Mortar and pestle * Notched stopper to hold thermometer * Ring stand * Rubber band * Thermometer * Universal clamp * Equipment – Part 2: * Balance, .001 g precision * Bunsen burner * Crucible and cover * …show more content…
Using tongs, remove crucible from clay triangle and place it on wire gauze. * Allow crucible to cool for 10 minutes. * Use analytical balance to find mass. Handle with tongs to avoid getting finger prints on crucible and lid. * Record mass in data table. * Add 2 g of alum crystals to crucible. Weigh crucible, cover, and crystals and record mass in data table. * Set crucible at angle in triangle held in ring on ring stand. Cover crucible loosely with crucible cover, and heat gently. Alum will melt, and water of hydration will evaporate. * After bubbling has stopped, heat sample more strongly for five minutes. * Turn off gas and remove burner. * Using tongs, remove crucible cover and place it on wire gauze on tabletop. With tongs, remove crucible from clay triangle and place it on wire gauze. * Allow crucible to cool for 10 minutes. * Measure and record mass of crucible, cover, and anhydrous alum. * Repeat procedure until constant mass is obtained. * Record final mass of crucible, cover, and anhydrous alum in data …show more content…
* Placing a hot object on a sensitive balance would cause convention currents in the air around the object. This would lead the reading on the balance to be unsteady. Also, when the object is hot it has more energy, so it would lead to having a bigger mass. * Comment on the results of the different tests used to verify that the sample tested was alum. * The first test was to determine the melting point of alum. The measured melting point that we got was 92.5 ℃. The literature melting point of alum is also 92.5℃. Also, during our flame test the flame turned purple which proved the presence of potassium ions. * What other tests could be used to verify the composition of alum? * You could perform a sulfate test to determine the percentage of sulfate that was present. You could also determine the percentage of aluminum or potassium in the crystals. V)
Analysis of Alum
* Purpose: * In this lab we performed several tests to determine if our crystals were actually aluminum potassium sulfate. * Procedures: * Materials: * Chemicals: * Aluminum potassium sulfate, 2.5 g * Equipment – Part 1: * 150 mL beaker * Bunsen burner * 2 capillary tubes * Mortar and pestle * Notched stopper to hold thermometer * Ring stand * Rubber band * Thermometer * Universal clamp * Equipment – Part 2: * Balance, .001 g precision * Bunsen burner * Crucible and cover * …show more content…
Using tongs, remove crucible from clay triangle and place it on wire gauze. * Allow crucible to cool for 10 minutes. * Use analytical balance to find mass. Handle with tongs to avoid getting finger prints on crucible and lid. * Record mass in data table. * Add 2 g of alum crystals to crucible. Weigh crucible, cover, and crystals and record mass in data table. * Set crucible at angle in triangle held in ring on ring stand. Cover crucible loosely with crucible cover, and heat gently. Alum will melt, and water of hydration will evaporate. * After bubbling has stopped, heat sample more strongly for five minutes. * Turn off gas and remove burner. * Using tongs, remove crucible cover and place it on wire gauze on tabletop. With tongs, remove crucible from clay triangle and place it on wire gauze. * Allow crucible to cool for 10 minutes. * Measure and record mass of crucible, cover, and anhydrous alum. * Repeat procedure until constant mass is obtained. * Record final mass of crucible, cover, and anhydrous alum in data …show more content…
* Placing a hot object on a sensitive balance would cause convention currents in the air around the object. This would lead the reading on the balance to be unsteady. Also, when the object is hot it has more energy, so it would lead to having a bigger mass. * Comment on the results of the different tests used to verify that the sample tested was alum. * The first test was to determine the melting point of alum. The measured melting point that we got was 92.5 ℃. The literature melting point of alum is also 92.5℃. Also, during our flame test the flame turned purple which proved the presence of potassium ions. * What other tests could be used to verify the composition of alum? * You could perform a sulfate test to determine the percentage of sulfate that was present. You could also determine the percentage of aluminum or potassium in the crystals. V)