The Analysis of Alum
Computer
The. Analysis of Alum
158
After a compound has been synthesized, tests should be carried out to verify that the compound fonned is indeed the compound desired. There are a number of tests that can be perfonned to verify that the compound is the one desired. In Experiment 15A, you prepared alum crystals, KAl(S04)z·12H 20. In Experiment 15B, you will conduct a series of tests to detennine if your crystals are really alum. The first test is to find the melting temperature of the compound and compare this value with the accepted (published) value for alum (92.5°C). The second test detennines the water of hydration present in the alum crystals. The third test is a chemical test to detennine the percent sulfate in your sample of alum.
OBJECTIVES
In this experiment, you will • • • • Detennine the melting temperature of a sample of alum. Detennine the water of hydration of a sample of alum. Detennine the percent sulfate of a sample of alum. Verify the chemical fonnula of a sample of alum.
MATERIALS
Part I, Melting Temperature Test Materials
Vernier computer interface computer Temperature Probe capillary tubes 150 mL beaker or Thiele melting-point tube mortar and pestle glass stirring rod
Part II, Water of Hydration Test Materials
alum crystals, KAl(S04)2·12H20 hot plate ring stand, ring, and wire gauze utility clamp cork or split stopper small rubber band
crucible with cover balance lab burner
Patt III, Percent Sulfate Test Materials
alum crystals, KAl(S04)z·12H20 ring stand, ring, and clay triangle tongs or forceps alum crystals, KAl(S04)z·12H20 0.20 M barium nitrate solution ring stand, ring, and wire gauze 50 mL or 100 mL graduated cylinders glass stirring rod
250 mL beaker watch glass to fit the 250 mL beaker balance Gooch crucible filter apparatus rubber policeman or other scraping tool
Advanced Chemistry with Vernier
15B -1
Computer 15B
PROCEDURE
Part I Determine the Melting Temperature of Alum
1. Obtain
The. Analysis of Alum
158
After a compound has been synthesized, tests should be carried out to verify that the compound fonned is indeed the compound desired. There are a number of tests that can be perfonned to verify that the compound is the one desired. In Experiment 15A, you prepared alum crystals, KAl(S04)z·12H 20. In Experiment 15B, you will conduct a series of tests to detennine if your crystals are really alum. The first test is to find the melting temperature of the compound and compare this value with the accepted (published) value for alum (92.5°C). The second test detennines the water of hydration present in the alum crystals. The third test is a chemical test to detennine the percent sulfate in your sample of alum.
OBJECTIVES
In this experiment, you will • • • • Detennine the melting temperature of a sample of alum. Detennine the water of hydration of a sample of alum. Detennine the percent sulfate of a sample of alum. Verify the chemical fonnula of a sample of alum.
MATERIALS
Part I, Melting Temperature Test Materials
Vernier computer interface computer Temperature Probe capillary tubes 150 mL beaker or Thiele melting-point tube mortar and pestle glass stirring rod
Part II, Water of Hydration Test Materials
alum crystals, KAl(S04)2·12H20 hot plate ring stand, ring, and wire gauze utility clamp cork or split stopper small rubber band
crucible with cover balance lab burner
Patt III, Percent Sulfate Test Materials
alum crystals, KAl(S04)z·12H20 ring stand, ring, and clay triangle tongs or forceps alum crystals, KAl(S04)z·12H20 0.20 M barium nitrate solution ring stand, ring, and wire gauze 50 mL or 100 mL graduated cylinders glass stirring rod
250 mL beaker watch glass to fit the 250 mL beaker balance Gooch crucible filter apparatus rubber policeman or other scraping tool
Advanced Chemistry with Vernier
15B -1
Computer 15B
PROCEDURE
Part I Determine the Melting Temperature of Alum
1. Obtain