Date: Sep 15, 2011
The purpose of this experiment is to verify the identity of the alum by finding the properties of the substance; melting point and mole ratio of the water to the anhydrous.
Every substance has unique characteristics which help to determine the identity of it. The actual values of the properties can be compared to the experimental values. In real life, this can be used to determine the unknown medicines.
The hypothesis is that the alum can be verified by finding the properties; the actual melting point of alum is 92.5(http://cookeatshare.com/popular/melting-point-of-alum) and the actual mole ratio of alum to water is 12:1 , By finding the melting point and alum to water mole ratio, it can be compared to the real values
Equipment Part 1:
Aluminum potassium sulfate (1.5 g)
150 mL beakers (3)
Bunsen burners (3)
Capillary tubes (3)
Mortar and pestle
Notched stopper (3)
Ring Stand (3)
Thermometer, 0c ~ 100c (3)
Glycerol (few drops)
Equipment part 2:
Aluminum potassium sulfate (6g)
Balance, 0.0001g precision
Bunsen burner (3)
Crucible and lid, 30mL (3)
Ring stands (3)
Pipe stem (3)
Wire gauzes (3)
Procedure part 1:
1. Pack the alum into a capillary tube with a length of 1 ~ 2 cm
2. Tie the capillary tube to the thermometer using a rubber band with it's opening upside down.
3. Dip the top of the thermometer into glycerol
4. Push the thermometer through the stopper
5. Fasten the stopper with a clamp
6. Fill the beaker with 150 mL distiller water covering the tip of the thermometer and the capillary tube in the beaker.
7. boil the beaker until the alum in the capillary tube dissolves
8. Recoded the temperature change at which the alum melts
9. Repeat step #1~8 for 2 more trials
Procedure part 2
1. Get a ring stand that has a ring clamp.
2. Place a clay pipe stem on top of the ring clamp and the Bunsen burner