Groups of 3.
Aggregation state lab – Carry out this entire lab in a fume hood! Heat samples slowly and
maintain control!
Eye protection and lab coat compulsory at all times. DO NOT wear vinyl gloves. Why?
Figure 1: Erlenmeyer flask
Before starting: SATURATE a hydrous solution with NaCl, discuss with your labmate how you would do this. How can
you be certain that your solution is saturated? This will be your stock solution for this lab.
Measure up 100 ml of distilled water in a beaker, and in a separate beaker 100 ml of the stock solution above. Add
magnetic stirring rods to both, but do not turn the hotplate on.
Measure the temperature of the water every 30 seconds, including 𝑡0 write your data down in a table (either digitally
or on paper) as you do the following:
A1: Add 1 ice cube to each beaker. Writing down the values, measure the temperature of both beakers for exactly five
minutes, every 30 seconds. When do they reach equilibrium?
A2: Set the hot plate to Heat #3. Measure both beakers until boiling starts, every 30 seconds.
When you’re done, clean and remove all lab equipment except for the hot plate.
B. Measure the melting point of your soap. Does it melt easily? What happens?
C. Determine the melting points of your samples here, follow the example set up.
Example: Sample 1 – Shiny, looks metallic, melts at – 923 𝐾𝑒𝑙𝑣𝑖𝑛 - 650 °𝐶, does not boil at these temperatures.
Sample 1: Coconut oil, do not heat beyond 180°𝐶 – Why?
Sample 2: White powder in beaker
Sample 3: Brown solid (heat slowly!)
Sample 4: White solid (heat slowly!)
Figure 2: Regular ol' beaker
Sample 5: Brown, elastic solid (Do not heat beyond 300°𝐶)
Mystery samples ahoy!
Which sample matches these descriptions? Why? Determine by melting point testing.
Is the mystery sample in the Erlenmeyer flask SUGAR or SALT?
Is the mystery sample in the small beaker SUGAR, LACTOSE or GLUCOSE. How can you find out?
Is the mystery pill in the beaker ibuprofen or paracetamol?
Your instructor will now perform a similar test on a different mystery sample.
Is the mystery sample in the crucible Al or Fe? Determine by melting point testing.
Is the sample above Al or Mg?
What is the sample in the beaker? Is it pure? Why can we not determine the melting point in this lab?
Figure 3: Round-bottomed flask