Experiment 3: Separating a Mixture of Sand and Salt

CHEMISTRY 100

Experiment 3: Separating a Mixture of Sand and Salt

Name:______

Partner’s name:______

Date:______

This report is due by the end of the lab session.

OBJECTIVE:

MATERIALS: One 150 mL beaker, one 250 mL beaker, funnel, iron ring, filter paper, wash bottle, scoopula, large watch glass, hot plate, glass stirring rod

PROCEDURE:

1. Record the mass of a small 150 mL beaker. Add approximately 20 g of the sand/salt mixture to the weighed beaker and record the mass. Calculate the mass of the sand/salt mixture used. Examine the mixture and record your observations.

2. Your task is to separate these two substances. Since salt is soluble in water, we can dissolve the salt to separate it from the sand. Add about 50 mL water to the beaker. Stir the mixture gently but thoroughly with a glass rod, taking care not to spill any of the water solution.

3. Heat the solution gently for a few minutes. Continue stirring.

4. Set up your filtration apparatus (refer to the demonstration at the front of the lab).

5. Weigh a 250 mL beaker and record the mass.

6. CAREFULLY decant the solution out of your small beaker into the funnel (make sure your filter paper is in the funnel!). Be sure to put the weighed 250 mL beaker under the funnel to catch the filtered liquid.

7. Wash the sand with about 5-10 mL of water. Remember to stir well to dissolve any remaining salt. Pour this solution into the filter paper and let it drain. After the liquid has passed through, transfer the remaining sand into the funnel. Use your wash bottle to rinse the 150 mL beaker with a SMALL amount of water. Pour the rinsings into the funnel.

8. After the liquid has been drained, carefully remove the filter paper and lay it flat on a large watch glass. Put the glass plate into the oven to dry the sand. After 10-15 min, the sand should be dry. While you are waiting for the sand to dry, skip to step 10.

9. Remove the sand from the oven and transfer the sand to a tared piece of weighing paper. Be sure to remove all of the sand from the filter paper. Record the mass of dry sand.

10. Place the 250 mL beaker containing the liquid remaining from your filtration (the filtrate) on the hot plate and gently boil the water to dryness. Let the beaker cool to room temperature (do not attempt to speed up the process by cooling the beaker with water – this will likely cause the beaker to shatter!).

11. Weigh the beaker containing the residual salt and record the new mass.

12. Clean all equipment and return to the proper locations.

DATA:

1. Mass of empty, dry 150 mL beaker______

2. Mass of the mixture of sand and salt plus the beaker before adding water______

3. Mass of the sand and salt mixture______

4. Describe the mixture of sand and salt:

5. Mass of empty, dry 250 mL beaker______

6. a) Mass of dried sand______

b) Mass of the dried salt and beaker______

c) Mass of the salt______

7. Describe the appearance of the dried sand:

8. Describe the appearance of the dried salt:

CALCULATIONS:

1. Calculate the percent (by mass) of salt in the sand/salt mixture:

mass of salt x 100% = % salt

mass of sand + mass of salt

______% salt

2. Calculate the percentage of sand in the mixture

mass of sand x 100% = % sand

mass of sand + mass of salt

______% sand

DISCUSSION:

1. Add the percentages of sand and salt together. If they do not add up to exactly 100%, suggest a reasonable explanation to account for the discrepancy.

2. Define the following terms:

a) soluble:

b) decanting:

CONCLUSION: