Name: ___________________________ Chemistry I Experiment

Separations of Mixtures

Introduction:

Physical separation is one method of determining whether a material is a mixture or a substance. There are two techniques of physical separation that will enable you to separate substances with different solubility. One is filtering which is an extremely useful laboratory procedure. The other involves evaporation; the solution is evaporated to dryness over a water bath.

In order to perform a physical separation of the sand and salt mixture, you must find a solvent that will dissolve one substance but not the other. Normally you would consult a solubility table or a chemical handbook for this information, but from your own experience, you know that water dissolves salt but it does not dissolve sand. Therefore water will be used to dissolve the salt and then filter paper and a funnel will physically separate the sand from the salt. Then the water will be evaporated from the salt-water mixture leaving the salt behind.

Objectives:

1. Using physical laboratory techniques of filtering and evaporating, separate a mixture

2. Calculate the percent error and determine sources of error in the experiment

Materials:

250 ml beaker, 125 ml beaker, ring stand, funnel, filter paper, watch glass, sand salt and water

Procedure:

1. Mass between 1.00 g and 1.50 g of the sand salt mixture. Record your mass. Describe its characteristics

2. Place the sand salt mixture in the 125 ml beaker and add 10 ml of water.

3. Label and mass a piece of dry filter paper and then fold it as shown.

4. Place the filter paper in a funnel, which is in a ring on a ring stand.

5. Label and mass a dry 250 ml beaker and then place under the funnel.

6. Carefully pour the sand salt mixture into the filter paper. Use the wash bottle to rinse the sand from the from the beaker

7. Rinse the sand in the filter paper with 3-4 ml of distilled water using the wash bottle to thoroughly rinse the salt water solution

8. Carefully remove the filter paper from the funnel and place it in the oven to dry. When dried, mass the filter paper and the sand. Describe the sand’s characteristics.

9. Using a hot plate, carefully evaporate the water from the salt water solution. When dried, mass the beaker with the salt crystals. Describe the salt’s characteristics.

Data Table:

Create a data table based on the procedure. There should be three columns tilted sample, mass, and observations. Reading through the procedure you should find 5 samples that need massing.

Analysis:

1. Determine the mass recovered of the sand and of the salt.

2. Calculate the mass of the sand and the salt after the filtering and evaporating.

3. Calculate the percent error of the sand recovered and the salt recovered.

Questions:

1. What are some characteristics of a physical change?

2. List at least two possible sources of error in the experiment that caused your team not to recover 100% of the original sand salt mixture.

3. Name another mixture that can be separated using the filtering technique. Include the solvent used.

4. Name another mixture that can be separated using the evaporating technique.

5. Describe how an iron- sulfur mixture can be separated.

Conclusion:

In your conclusion, make specific references to the objective(s) and results. The conclusion should also include sources of experimental error and suggestions for improvement that are thoughtful and well written. Be concise!