Total Dissolved Solids s6

Name: ______Date: ______Period: ______Page: ______

Distillation of Copper Sulfate

Introduction: The components of a homogenous mixture are difficult to recognize due to the uniform appearance of the solution. A solute dissolved in a solvent is not visible, so the components must often be separated to verify their existence and identify them. Distillation is the process of changing a liquid, or a mixture of liquids to vapors and then cooling the vapors back to the liquid states. It is a means of separating a homogenous mixture (a solution) into its component parts. In this activity, you will use the process of distillation to separate the components of a copper sulfate solution. The process of distillation separates the components of a mixture by virtue of the differences in their boiling points.

Objectives: When you have completed this activity, you should be able to separate the components of a homogenous mixture by distillation and use computer technology to analyze data. Data:

1. Initial observations:______

2. The initial temperature of the solution: ______

3. Temperature when first drop falls: ______

4. Final Observations: ______

Time Temp (°C) Time Temp (°C) Time Temp (°C) Time Temp (°C) 0.0 min 4.0 min 8.0 min 12.0 min 0.5 min 4.5 min 8.5 min 12.5 min 1.0 min 5.0 min 9.0 min 13.0 min 1.5 min 5.5 min 9.5 min 13.5 min 2.0 min 6.0 min 10.0 min 14.0 min 2.5 min 6.5 min 10.5 min 14.5 min 3.0 min 7.0 min 11.0 min 15.0 min 3.5 min 7.5 min 11.5 min 15.5 min

Graph: Sketch the graph of the Copper Sulfate Distillation Analysis: 1. Compare the appearance of the solution in the distilling flask before heating with the appearance of the distillate. Suggest a reason for any observed difference.

2. Was the separation was complete? How do you know?

3. Is this process of separation an example of a chemical change or a physical change? Explain.

4. What did you notice about the temperature while the distillate was being collected?

5. Use the chart, Boiling Points of Several Liquids, to answer the question.

Boiling Points of Several Liquids benzene 80.2ºC ethyl alcohol 78.4 ºC chloroform 61.3 ºC carbon disulfide 46.3 ºC

Do you think a good separation of a mixture of ethyl alcohol and benzene could be achieved by distillation? Explain you answer.

6. A mixture containing 2 different liquids (water and glycerin) was separated by distillation. A temperature- time graph was constructed as the distillation progressed. The boiling points of water and glycerin are 100°C and 125°C respectively.

a. What liquid(s) come over during interval I?

b. What liquid(s) come over during interval II?

c. What liquid(s) come over during interval III?

d. What liquid(s) come over during interval IV?