Chemistry Period 3 Group 5 Section 2: Matter October 7, 2010 Hailey Benesch

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1 Chemistry Period 3 Group 5 Section 2: Matter October 7, 2010 Hailey Benesch

2 Title: Mixture Separation Lab Objective: The goal of this experiment is to clearly determine what the unknown substance is by testing certain physical properties of the substance. The physical properties we are testing are the substances magnetic capability, conductivity, absorbency of water, separation in water and its density. We will also be making observations about its smell, texture, color, form of state and etc. Hypothesis: If we test certain physical properties of the unknown substance (conductivity, magnetic capability, absorbency of water, density and its separation in water) then we will be able to figure out what the substance is because we will find out enough physical characteristics to compare it to other substances so we can figure out what it is. Materials 1 Conductivity meter 1 magnet Water or a sink Various beakers Beaker/container for unknown substance Gloves (two/one pair at least for each group member) Protective eye wear (one for each group member) 1 scale At least 500. ml of unknown substance Paper Procedure (* means to lightly compact the substance when measuring it) 1. Obtain the materials needed for the experiments. 2. Put on glasses and gloves. 3. Make general observations about the physical characteristics of substance (color, smell and etc.). 4. Record observations about the material. 5. First take 100. ml of the substance* and spread evenly over a piece of paper that is on a flat surface. 6. Then take one magnet and wave the magnet slowly over the substance about one centimeter above the substance. 7. Check and see if the magnet picked up any of the substance. 8. Measure how much substance the magnet picked up. 9. Record the results. 10. Repeat steps 5-9 if needed. 11. Dispose of the material used into their proper places/ slop containers. 12. Take 100. ml of the substance* and put into a 250mL beaker. 13. Add 25. ml of water slowly to the sample. 14. Allow at least 10 seconds for the sample to absorb the water.

3 15. Repeat steps until the sample cannot absorb any more water (layer of water appears on top). 16. Measure the amount of water on top of the sample (in ml) and subtract from the amount of water you added. 17. Record how much water the substance absorbed. 18. Repeat steps if needed. 19. Dispose of the used materials into their proper places or slop containers. 20. Take 100.mL of the substance* and put in a 200mL beaker. 21. Take the conductivity meter and place its prongs into the substance, make sure that the prongs are not touching the glass. 22. Using the back of the conductivity meter as a guide, determine the conductivity of the material. 23. Record the amount of conductivity of the material. 24. Repeat steps if needed. 25. Dispose of the used materials into their proper places or slop containers. 26. Measure 100.mL of the substance*. 27. Take a piece of paper on a scale and then zero/tare out the paper. 28. Take 100.mL of the substance and put on the paper that is on the scale (make sure it is only the substance and that the container is not included). 29. Record the mass of the substance to the nearest tenth of a gram (make sure the measurement of mass is in grams). 30. Once you know the mass of the substance, divide the mass by 100. ml to get the density of the material (d= m/v). 31. Record the materials density. 32. Dispose of the used materials into their proper places or slop containers. 33. Measure 200. ml of water in a 250 ml beaker. 34. Take about one spoon full of the substance (25 ml.) and put into the water. 35. Stir the substance and then let the substance settle for at least 15 minutes. 36. Record the appearance and result of the mixture of water and material. 37. Dispose of the used materials into their proper places or their slop containers. 38. Clean up. 39. Make additional research if needed to be able to come to a conclusion. 40. Record all data and results and write a conclusion, make sure to include errors as well. Data and Calculations General Observations About the Unknown Substance o Texture of the unknown substance is grainy with some larger pebbles, very similar to sand s texture. o The substances form of state is solid. o The substance color is generally brown with varying colors of white brown, black, and red granules. o The substance is slightly wet and can clump/stick together well, similar to sand. o The smell of the substance is an earthy rotten smell. Data from Test One: Magnetic Capability 0 ml of the substance stuck onto the magnet. This concludes the substance has no magnetic capability.

4 Data from Test Two: Absorbency of Water 100 ml of the substance absorbed 25 ml of water. Data from Test Three: Conductivity of the Substance When sticking the prongs of the conductivity meter into the substance, neither the green nor the red light turned on. According to the back of the conductivity meter, where there were directions on how to read the conductivity meter, because no lights turned on, the substance cannot conduct electricity. Data from Test Four: Density of the Material o When we weighed 100. ml of the substance, the mass was grams. To figure out the density, we took the mass of 100. ml of sand and divided it by 100. ml. o grams/100. ml (density=mass/volume). o This calculation resulted in g/ml. Then we applied the rule of significant figures and since the measurement with the least accuracy is 100. ml and it only has three significant figures, the actual measurement is 1.52 g/ml. o The density of this substance is 1.52 g/ml. Data from Test Five: Separation of the Material in Water After at least 15 minutes of letting about one spoon full of substance (or 25 ml) settle in 200 ml of water, the grainy substance settled at the bottom and a very light layer of light brown silt settled at the edges. The water above the substance is brown and murky. There are also small bubbles on the edges of water on the rim of the beaker. Additional Data: o According to Troy Shinbrot, a physicist at Rutgers University in Piscataway, New Jersey, sand, under normal circumstances, will not conduct electricity. o Sand has a similar density( 1.59 g/ml) to the density of the unknown substance (1.52g/mL). o When taking beach sand and putting it into water it does not have brown murky water when it separates. RESULTS: The unknown substance o Does not conduct electricity o Does not have magnetic capabilities o Has a density of 1.52 g/ml o Only absorbs 25 ml of water per 100 ml of water o When put into water separates into grainy material at the bottom while the water is brown and murky. o Substance has similar physical characteristics to sand. o Sand does not conduct electricity. o Sand does not have magnetic capabilities. o Sand has similar water abortion as substance. o Separation of sand in water and the substance in water is not the same

5 o Sand has a density of 1.59 g/ml similar to the substance. o Because of similar physical characteristics as listed above I believe that part of the substance is sand. CONCLUSION: From the results of the procedure/experiment, I believe that the unknown substance is a mixture of sand and another substance I cannot identify. The reason why I believe part of the mixture is sand is that it has very similar physical qualities with sand. Like sand, the substance does not have the capability to conduct electricity. This substance also did not have magnetic capabilities and sand also does not have magnetic capabilities unless in contains the mineral of black magnetite. This also indicates that part of this substance could have been sand without black magnetite. The density of this substance (1.52 g/ml) is also very similar to sand, which has a density of 1.59 g/ml and has similar absorption of water as sand does (the substance can absorb 25 ml of water per 100 ml of the unknown substance). This substance also looks, smells, and feels very similar to sand. My other conclusion is that this sand is also mixed with something else because of when I conducted the separation lab. When the substance settled, there was a grainy substance on the bottom, but there was a very thin layer of brown silt starting to form on top of the sand. Also the water above was brown and murky. Regular beach sand does not have brown silt in it indicating that this sand had been mixed with something else, which I could not identify. The reasons I could not identify it was because I do not know any similar brown silt substance that has this substances characteristics, and I did not conduct specific enough experiments to determine what the brown substance is, which leads me to my errors. Errors: One of the major errors I had was measuring. Since we used millimeters and beakers to measure our unknown substance it was hard to get an accurate measurement of the substance. Also, it depend if you wanted the substance compacted or not in your measurements. Lack of accurate measurements also led to a lack of accurate results. For example the density of the material is not exactly 1.59 g/ml like sand is, either indicating faulty measure or the other unknown brown substance changed the density of the product. Another error is not doing specific enough experiments to figure out what all of the substance was. The experiments helped to clarify only part of the mixture, but not all of it. So we did not conduct enough experiments to find out enough physical characteristics so we could compare it to other substances to figure out what it was. We only conducted enough experiments to figure out part of the mixture. To prevent these errors from happening next time, we need a more precise way to measure the unknown substance and to expand our experiments so we get a more wide range of data. I would like to conduct this experiment again with different measuring tools and more precise experiments and see what would happen.