Cyclohexane Prac Report Week 7
14 Cyclohexane -­‐ Freezing and Melting Point 12 10 Temp (ºC) 8 6 4 2 Temp (ºC) 0 0 500 1000 1500 2000 2500 3000 -­‐2 -­‐4 -­‐6 Time (s) Aim: The aim of this experiment is to discover the melting
and freezing point of Cyclohexane.
Method:
1. Prepare and gather all the need equipment, the items
need include:
• 2 Boss heads and Clamps
• 3 Beakers filled with water, ice and salt with ice
• Digital Thermometer
• Retort Stand
• Test Tube filled with Cyclohexane
• Measuring Cylinder
2. When all the gear needed is at hand fill the test tube with
10mL of Cyclohexane.
3. Clamp the test tube in a vertical position.
4. Clamp the digital thermometer so it is about 1cm into the
Cyclohexane.
5. Lower the test tube into a beaker containing ice.
6. When the Cyclohexane is 10 degrees Celsius swap the
ice with salt with ice.
7. Continue recording temperature until it reaches -5
degrees Celsius.
8. Replace the Salt and ice mixture with cold water (which
should melt the Cyclohexane)
9. Record until 15 degrees Celsius.
Conclusion:
1. The melting and freezing point of the Cyclohexane
was around 5 degrees Celsius. The ice brought the
temperature down to around 6 degrees Celsius. We
then replaced it when the temperature loss was neutral
with the ice and salt mixture. The salt and ice mixture
brought it right down but slowed dramatically when it
was around -1 degrees Celsius. Finally we brought the
temperature up with a beaker of normal water to
around 10ºC.
2. The plateau occurred we were not stirring and we had
not mixed the salt correctly. As you can see in the
graph, when we did do that there was an immediate
drop.
3. The cyclohexane froze at around 6 – 5ºC. You can see
this on our graph because at this temperature it drops
quite rapidly.
4. I think the water, ice and salt mixture did not freeze
the water when it got below 0ºC because the salt
brought the waters freezing point down.