Lab 1- Simple & Fractional Distillations of a Mixture: Water & Methanol PDF

Preview

Summary

Lab Report, got a good grade!...

Description

Nicole Bolling CHEM 3105-313 TA- Idris Olukoya Simple & Fractional Distillations of a Mixture: Water & Methanol

02/08/2021

LAB REPORT: EXP. 1 1. PURPOSE The purpose is to perform simple and fractional distillation with a methanol and water mixture. Additionally, determine which distillation method is most effective.

2. REACTION & PHYSICAL PROPERTIES TABLE i.

Components: i.

Methanol- CH3OH

ii. Water- H2O

COMPOUND

MW

AMOUNT

BP(CELSIUS)

METHANOL

32.05

20.0ML

65

WATER

18.02

20.0ML

100

3. SAFETY WITH METHANOL A. Prevention

i.

Wash exposed skin after handling

ii.

Don’t eat or drink when using this product

iii.

Wear protective gloves and clothing

iv. v.

Do not breathe in fumes

vi.

Allow enough space to work in

Keep away from hot surfaces

B. Response to Chemical Injury

i. ii.

Inform TA as soon as possible

iii.

Rinse area of contamination and/or move person to fresh air environment

Call Poison Center or doctor/physician

C. Disposal

i.

Dispose in an approved waste disposal plant

4. PROCEDURE A. With my partner, place 40mL of the 50/50 mixture in a 100mL round bottom flask and add a few boiling stones. B. Place flask on hot plate and clamp in place with blue clips on horizontal joints.

i.

Make sure bulb is below side arm of the 3- way adapter.

C. Set up simple/fractional distillation apparatus as outlined.

i.

Use thermometer adapter and use clamp to support water condenser and vacuum adaptor (should not rest on graduated cylinder).

D. Turn on hot plate to 300°C for the simple distillation and 350°C for the fractional distillation.

E. Adjust the rate of heating so that the distillate is collected at a rate of approximately one drop every 1-2 seconds.

F. Record temperature of the distillation head for every 2mL of distillate. i.

If my graduated cylinder markings start at 3mL, start the data collection at 3mL and then measure the temperature for every 2mL of distillate afterwards.

G. Continue distillation while recording the temperature until the temperature approaches 100°C and remains constant. H. Plot graph of temperature versus mL of distillate for each of the distillations. I.

Return blue keck clips to the hood when experiment is complete.

5. DATA/OBSERVATIONS A. I observed the temperature of the Methanol/Water mixture after every 2mL that was distilled into the graduated cylinder until the temperature reached 100°C. At the beginning of the simple distillation process, the temperature went up slowly in the round bottom cylinder. However, as the experiment went on, the temperature increased slightly quicker once the distilled methanol reached about 18mL. At 22mL of distilled methanol, the mixture plateaued at 100°C. Overall, the temperature increase was a consistent climb overall. I stopped the experiment once the temperature reached 100°C and concluded that the mixture in the round bottom cylinder was no longer a mixture but just water. In the facilitated diffusion experiment, the temperature slowly climbed at the beginning and then spiked until it reached 100°C at 27mL.

2

6. RESULTS A. There were no specific calculations for this experiment.

Simple Distillation Temperature (°C )

120 100 80 60 40 20 0 2mL

4mL

6mL

8mL

10mL 12mL 14mL 16mL 18mL 20mL 22mL

Total Volume of Distillate Collected (mL)

Facilitated Diffusion Temperature (°C )

120 100 80 60 40 20 0 3mL 5mL 7mL 9mL 11mL 13mL 15mL 17mL 19mL 21mL 23mL 25mL 27mL

Total Volume of Distillate Colected (mL)

7. CONCLUSION/DISCUSSION A. The main purpose of this experiment was to perform the simple and fractional distillation of methanol and water and determine which was more effective. In the simple distillation, there was a steady increase in the temperature of the methanol/water mixture rather than a rate of increase. In the fractional distillation, it 3

took longer to distill, and it also did not follow a consistent rate. The distillation that was more effective was the simple because it was consistent, and it completely distilled faster than the fractional (5mL more during the fractional distillation). These findings could’ve been affected because I was not able to connect the rubber tubes to the correct openings on the cold-water condenser on the first try. If I had executed this technique from the start, the temperature findings could’ve been altered.

8. POST-LAB QUESTIONS A. Why is it important to have a boiling chip present in the boiling flask when distilling liquid mixtures?

i.

It is important to have boiling chips because it ensures that the liquid mixture boils evenly over time without boiling over.

B. What role does the steel wool serve in the fractional distillation setup used during the experiment?

i.

It serves to increase the surface area in the tube and can improve the separation of the methanol and water.

C. During the beginning of the distillation experiment (either simple or fractional), what compound in the starting water/methanol mixture predominates in the distillate? Briefly explain why.

i.

The compound that predominates at the beginning of the experiment is methanol because it has a lower boiling point and will distill first.

D. As the distillation continues eventually the observed temperature of the vapor will approach but never exceed 100°C (assuming there is nothing wrong with the thermometer, no bubbles in the alcohol column, etc.). Why is 100 °C the upper limit observable in the experiment?

i.

Since methanol has a boiling point of 64.7°C and boiling chips prevent the liquid from boiling over, the liquid will not exceed 100°C since this is water’s boiling point.

4...