Separation Of Mixtures By Physical Means

Separation of Mixtures by Physical Means

Name: ______Date Performed: ______Due Date:______

Lab Partners: ______

PreLab Discussion: Substances can be physically combined without producing new substance(s). That is, the individual substances will retain their identity (physical properties such as density, particle size, molecular polarity, boiling point and freezing point, solubility, color, smell and taste) rather than taking on a new one(s).

If a combination does not experience a chemical reaction to become a new substance, it can be separated using physical techniques. This proves that the substances were merely occupying the same space and therefore categorized as a mixture of pure substances.

If a chemical reaction occurs, new substances are produced with new identities and physical properties. These too can be separated, but it would require new chemical reactions to achieve it.

Examples of Physical techniques used for separating mixtures include: - Evaporation - Distillation - Centrifugation - Filtration - Decantation - Chromatography

Objective: In this lab you will prepare a simple mixture of substance and, using their unique physical properties, separate them. Once separated, you will discover how accurate your techniques were by calculating the percent by mass recovered compared to the original amount. In other words - percent error.

You will also be asked to identify the reasons why you did not recover the entire original amount of each substance (reasons for error), suggest ways to improve your technique and suggest areas where these techniques may be of practical use.

HYPOTHESIS: If the substances that have been combined can be ______, then they must be a ______.

Materials: - 50 Ml beaker - Evaporation Dish - Scale - Test Tube - Hot Plate - Weighing Boat - Test Tube Rack - Goggles - Graduated Cylinder - Funnel - NaCl(s) - Wash bottle - Filter Paper - H2O(l) - Tongs - Anise Seeds Safety: - Wear your safety goggles at all times - No horseplay will be tolerated - Use tongs to maneuver hot items - Do not return unused reagents to their original container - Read and perform all procedures as directed

Procedures: (remember to cross them out as you go)

A. PREPARE THE MIXTURE 1. Measure the mass of the evaporation dish in grams and record on Data Table 1 2. Measure 10 mL of H2O(l) 3. Pour the H2O(l) into the 50 mL beaker 4. Measure 1.0g of NaCl(s) (Table Salt) and record on Data Table 1 5. Pour the NaCl(s) into the H2O(l) and swirl until it completely dissolves 6. Place a weighing boat on the scale and tare/zero it 7. Measure 0.3g to 0.5g of anise seeds and record it on data table 1 8. Add the anise seed to the mixture and swirl

B. SEPARATION – Goal: Separate all the individual substances from the mixture 1. Devise an efficient strategy for separating the NaCl(s) and the anise seeds from the H2O(l).

______

2. Discuss your plan with your teacher. Teacher Initials ______

Calculations: ANALYSIS (in your lab report, please do not forget to provide the calculations) 1. Using the information from Data Table 1 and 2, calculate the percent by mass of the substance you recovered compared to the original amount. In other words - percent error.

2. Use the below formula to calculate the Percentage of the original substance you were able to recover. Recovered Amount in grams – Original Amount in grams % by mass Recovered = ------(100) Original Amount in grams

Data: (in your lab report, please do not forget to provide the Data Tables)

Date Table 1

Mass of Evaporation Dish (g) Original Mass of NaCl(s) (g) Original mass of the Anise Seeds

Data Table 2

Recovered mass of % by mass NaCl(s) Recovered mass of the Anise % by mass Anise the NaCl(s) (g) Recovered Seeds (g) Seeds Recovered

Questions: 1. Which physical properties were exploited to make the separation of the Anise Seeds possible?

2. Which technique was utilized?

3. Which two physical properties were exploited to make the separation of the NaCl(s) form H2O(l) possible?

4. Which technique was utilized?

5. Suggest another mixture that can be separated using filtration. Provide a supportive argument that identifies the physical properties being exploited.

6. Suggest another mixture that can be separated using evaporation. Provide a supportive argument that identifies the physical properties being exploited.

7. Research and report on the following: Crude oil is a mixture of several substances that are used by mankind to produce the products we rely on. - Describe the method used to separate these substances. - Identify the physical property that makes this possible - Identify three products made from the separated substances and state how they impact your world. - * include two sources of information and do not “Cut and Paste”. This would be plagiarism. Conclusion: Be sure your conclusion relates to the objective and follows the Rubric provided. Please do not forget to include reasons for error and suggestions for improvement.

Provide this page to Students only after they attempted to devise their own plan for separation

B. SEPARATION – Goal: Separate all the individual substances from the mixture

1. Fold a piece of filter paper in half two times and open to form a cone that can be placed into a funnel.

2. Place the neck of the funnel into a test tube that has been nested in a test tube rack.

3. VERY SLOWLY pour the mixture onto the filter paper within the funnel until all the liquid has run through it.

4. Remove the Anise Seeds from the filter paper and measure the mass that have been recovered and record it on Data Table 2.

***A COLD EVAPORATION DISH LOOKS LIKE A HOT ONE. PLACE THE BACK OF YOUR HAND NEAR IT TO DETERMINE ITS AVERAGE KINETIC ENERGY (TEMPERATURE)

5. Place the liquid (solution of ______(l) and ______(aq)) in the COLD evaporation dish.

6. Using tongs, careful place the evaporation dish on the HOT PLATE.

7. While waiting for the water to boil off (Evaporate), perform the first few tasks in Procedure C. 8. After all of the H2O(l) has been evaporated, use the tongs to transfer it to the scale closest to the hot plate. Measure the mass of the evaporation dish and ______.

9. Taking into account the mass of the evaporation dish along, calculate the mass of the NaCl(s) you were able to recover and record it on Data Table 2.

***Check your work here. The mass of the recovered NaCl(s) should be less than the original. If it isn’t, ask for help.