Identifying Unknown White Compounds Lab Report
_____________________________________________
Project 3: Identifying the Unknown White Compound by Testing Physical and Chemical Properties
_____________________________________________
Michigan State University
Chemistry Lab 161 Section 27
19 October 2017
Friday 11:00-1:50
Introduction
For this experiment, there was an unknown white compound that had to be identified. By testing this compound for different properties it made making an educated guess easier to determine what this compound was so it could be disposed of properly. To attempt to discover our unknown compound, the tests that will be performed will be: solubility test, pH test, physical property test, two precipitate tests, and temperature test with solubility. …show more content…
Each of these tests are important because they help determine properties of the unknown compound.
Solubility is highly important because there are many observations that could be made such as a phase change and to see how the compound reacts with the solvent (water) and once temperature becomes another variable and there are more observations that can be made and for most compounds, the solubility increases with temperature.1 The pH test is important because it tests whether a compound is acidic or basic, this then determines a lot about the compound because it cannot be both. With the pH strips, it gives a more exact answer that allows strips to be compared to see if they are similar.2 The final important test is the precipitate test, this shows if two solutions are soluble when they are mixed. If it doesn’t mix and there is a obvious precipitate in the bottom then it passed the test. If the mixture is clear, then it failed the test and the two solutions are not precipitates of each
other.3
Research information about each experiment and why it’s important The lab supplied 15 known compounds and one of the known compounds had to be our unknown compound. Therefore, around half a dozen experiments were done to test certain properties of this unknown compound and by using the known compound and deductive reasoning, the certainty level of the hypothesis was high.
Experimental Details
To determine the unknown compound, six experiments were done over the course of two weeks. The first week was dedicated to having a good idea what the unknown compound was and the second week was when it was certain what the unknown compound was.
Solubility Test was done to identify an initial property of the unknown and to get an idea of which known compounds could be taken of the list of the potential identity of the unknown. This test was done by mixing a gram of the compound in water in a beaker and observing if the powder dissolved or if it didn’t. Once the list of potential compounds was shortened, the solubility was tested of the couple knowns that were left. While testing the solubility, observations during the reaction were taken to see if the unknown and known were the same.4
Using pH test strips and the color indicator tested the pH of the unknown and all the knowns. After it was determined that the pH of the knowns were far from the pH of the unknown, they were able to be crossed of the list of potential matches for the unknown. This test was noticeably the best indicator for what the match was for the unknown. It helped determine which compounds the unknown was definitely not because each compound has a specific pH.
Physical Property Test was done by all the members of the lab as a final determinant to see if the unknown and the sodium sulfate looked a like. Both of the compounds had a similar white, granular resemblance. In addition to the physical look of the two compounds, a smell test was also done. In this test, the two compounds were wafted as to not damage the noses of the people smelling with any dangerous fumes. The two compounds were odorless, further deducting they are the same.
Precipitate Test was done with Calcium Nitrate and Calcium Chloride because they are known precipitates of Sodium Sulfate, a solution of those two compounds were mixed with the separate solutions of Sodium Sulfate and the unknown compound (1 gram of the compounds in beaker of 100mL of water). If the unknown had the same reaction as Sodium Sulfate, then there could be a higher confidence level for our answer.
Temperature test was done to identify phase changes in Sodium Sulfate. Sodium Sulfate solution and a solution of the unknown was heated to 32 degrees Celsius by and observations were made regarding any phase changes or reactions that occurred with the solutions.4
Precipitation to Reaction with Hydrochloric acid and calcium Carbonate. First 1 mL of Calcium Carbonate was added to 0.1mL Hydrochloric acid until it was dissolved. From then, water was added and then 1 mL of the unknown was added into it which formed a mild reaction. After the reaction took place then some dissolving took place but for the most part it remained cloudy. From there that reaction was compared to the other reaction previously done and found there was similarities in their reactions.5
Results
Solubility Test: The unknown was soluble in water, but if the compound wasn’t mixed it turned into a hard substance at the bottom of the beaker. Once it was mixed, though, it completely dissolved in water.4 pH Test: The pH of the unknown indicated a neutral 7 and the pH of the other knowns are as shown below.
NaCl
7 or 8
KCl
4
Na2SO4
7
CaCl2
4
MgSO4
8
Na2CO3
10 or 11
K2SO4
6
KNO3
6-7
Ca(NO3)2
6-7
NH4CO3
8 or 9
NH4Cl
11
(NH4)2SO4
5-6
CaCO3
7-9
MgCO3
8
CH3CO2Na
7 or 8
Physical Property Test: Unknown had granular properties, very white. Looked like cane sugar. The smell test indicated no odor.
Precipitate Test: this test indicated that Calcium Nitrate (Ca(NO3)2 and Calcium Chloride (CaCl2) are precipitates of the unknown. It was shown by a diluted, white bottom in the test tube.
Temperature: The solution wasn’t mixed well enough so the compound hardened in the bottom of the beaker, but once the solution was heated the hardened compound had a phase change and it completely dissolved in the water. The solution of Sodium Sulfate had the same reaction.4
Precipitation to Reaction: The Hydrochloride and Calcium Carbonate Solution was mixed with the unknown and the sodium sulfate and it reacted to create a precipitate, so it can be deducted that HCL and Calcium Carbonate was precipitated to Sodium Sulfate and the unknown.5
Discussion
During the experiment, it was very hard to have an explicit procedure since there was a lot of deviating from the plan and doing experiments so it was certain what the unknown sample was actually Sodium Sulfate. With high certainty it can be said that because the second week’s reaction were both the same, the unknown was Sodium Sulfate. One observation that was noticed during the solubility and the temperature test that even though the compound was soluble in water, if there was too much of the compound, not all would dissolve. This would leave a hardened version of the compound in the bottom of the beaker. The main observation that was noticed was the fact that once the solution was heat up, the hardened compound at the bottom of the beaker dissolved. This is because compounds become more soluble in higher temperatures.1 It is not hard to interpret the results of this project just because it is very explicit and it is very certain that the unknown substance was indeed Sodium Sulfate, but the tests that were done help give a rationale of the decision that the unknown was Sodium Sulfate the chemical equations make it more certain. The precipitate reaction of, Ca(NO3)2 (aq)+ Na2SO4 (aq)→ CaSO4 (s) +(NO3)2Na2(aq), explains the reaction system of Calcium Nitrate and Sodium Sulfate. The precipitate in that reaction ended up being the Calcium Sulfate.3 This is important because when two solutions mix, the precipitate can be found by writing down the chemical reaction. The solubility test showed the same results with empirical data. Na2SO4 (s) + H2O→ Na2 (aq) + SO4 (aq) + H2O, the solid compound reacted with the water and phased changed into a liquid, this dissolving process is important because not all compounds dissolve in water and it further exemplified how Sodium Sulfate is the unknown. The explicit data from the chemical equations aids in the identification of the unknown because the unknown had the same precipitate as the known Sodium Sulfate. If there were more variables, it would be harder and there would need to be more explanation for the results that were collected.
Conclusion
Based on all the experiments that were done, it is easy to say that the unknown white compound is Sodium Sulfate. All the tests that were done on the unknown showed the same properties as Sodium Sulfate. It is important the reBased on the information the MSDS for the compound says that there could be skin irritation and it could cause vomiting if ingested.6 To synthesize Sodium Sulfate is very dangerous to synthesize because one of the reactants is Sulphuric Acid and that is a dangerous acid. The products of the reaction end up being Na2SO4+10H2O, while the reactants are H2SO4+ Na. This compound is used in detergents and in the process of paper pulping.7
References
White Paper. Solubility: Importance, Measurements, and Application. www.crystallizationsystems.com (accessed Oct. 17 2017)
Prolom Water. The Significance of the pH Value. http://prolomvoda.com/prolom_water.php?pro_id=23 (accessed Oct. 17, 2017)
Chemistry Libre Texts. Precipitation Reactions. https://chem.libretexts.org (accessed Oct. 17, 2017)
Lab Archives. Data and Notes Project 3 Rushil and Miranda. www.labarchives.com (accessed Oct. 17, 2017)
Lab Archives. Data and Notes Project 3 Kau Boayue. www.labarchives.com (accessed Oct. 17, 2017)
Science Lab. Material Safety Data Sheet for Sodium Sulfate. http://www.sciencelab.com/msds.php?msdsId=9927278 (accessed Oct. 17, 2017)
General Chemistry. Sodium Sulfate. www.vias.org/genchem/inorgcomp_sodiumsulfate.html (accessed Oct. 17, 2017)
Project 3: Identifying the Unknown White Compound by Testing Physical and Chemical Properties
_____________________________________________
Michigan State University
Chemistry Lab 161 Section 27
19 October 2017
Friday 11:00-1:50
Introduction
For this experiment, there was an unknown white compound that had to be identified. By testing this compound for different properties it made making an educated guess easier to determine what this compound was so it could be disposed of properly. To attempt to discover our unknown compound, the tests that will be performed will be: solubility test, pH test, physical property test, two precipitate tests, and temperature test with solubility. …show more content…
Each of these tests are important because they help determine properties of the unknown compound.
Solubility is highly important because there are many observations that could be made such as a phase change and to see how the compound reacts with the solvent (water) and once temperature becomes another variable and there are more observations that can be made and for most compounds, the solubility increases with temperature.1 The pH test is important because it tests whether a compound is acidic or basic, this then determines a lot about the compound because it cannot be both. With the pH strips, it gives a more exact answer that allows strips to be compared to see if they are similar.2 The final important test is the precipitate test, this shows if two solutions are soluble when they are mixed. If it doesn’t mix and there is a obvious precipitate in the bottom then it passed the test. If the mixture is clear, then it failed the test and the two solutions are not precipitates of each
other.3
Research information about each experiment and why it’s important The lab supplied 15 known compounds and one of the known compounds had to be our unknown compound. Therefore, around half a dozen experiments were done to test certain properties of this unknown compound and by using the known compound and deductive reasoning, the certainty level of the hypothesis was high.
Experimental Details
To determine the unknown compound, six experiments were done over the course of two weeks. The first week was dedicated to having a good idea what the unknown compound was and the second week was when it was certain what the unknown compound was.
Solubility Test was done to identify an initial property of the unknown and to get an idea of which known compounds could be taken of the list of the potential identity of the unknown. This test was done by mixing a gram of the compound in water in a beaker and observing if the powder dissolved or if it didn’t. Once the list of potential compounds was shortened, the solubility was tested of the couple knowns that were left. While testing the solubility, observations during the reaction were taken to see if the unknown and known were the same.4
Using pH test strips and the color indicator tested the pH of the unknown and all the knowns. After it was determined that the pH of the knowns were far from the pH of the unknown, they were able to be crossed of the list of potential matches for the unknown. This test was noticeably the best indicator for what the match was for the unknown. It helped determine which compounds the unknown was definitely not because each compound has a specific pH.
Physical Property Test was done by all the members of the lab as a final determinant to see if the unknown and the sodium sulfate looked a like. Both of the compounds had a similar white, granular resemblance. In addition to the physical look of the two compounds, a smell test was also done. In this test, the two compounds were wafted as to not damage the noses of the people smelling with any dangerous fumes. The two compounds were odorless, further deducting they are the same.
Precipitate Test was done with Calcium Nitrate and Calcium Chloride because they are known precipitates of Sodium Sulfate, a solution of those two compounds were mixed with the separate solutions of Sodium Sulfate and the unknown compound (1 gram of the compounds in beaker of 100mL of water). If the unknown had the same reaction as Sodium Sulfate, then there could be a higher confidence level for our answer.
Temperature test was done to identify phase changes in Sodium Sulfate. Sodium Sulfate solution and a solution of the unknown was heated to 32 degrees Celsius by and observations were made regarding any phase changes or reactions that occurred with the solutions.4
Precipitation to Reaction with Hydrochloric acid and calcium Carbonate. First 1 mL of Calcium Carbonate was added to 0.1mL Hydrochloric acid until it was dissolved. From then, water was added and then 1 mL of the unknown was added into it which formed a mild reaction. After the reaction took place then some dissolving took place but for the most part it remained cloudy. From there that reaction was compared to the other reaction previously done and found there was similarities in their reactions.5
Results
Solubility Test: The unknown was soluble in water, but if the compound wasn’t mixed it turned into a hard substance at the bottom of the beaker. Once it was mixed, though, it completely dissolved in water.4 pH Test: The pH of the unknown indicated a neutral 7 and the pH of the other knowns are as shown below.
NaCl
7 or 8
KCl
4
Na2SO4
7
CaCl2
4
MgSO4
8
Na2CO3
10 or 11
K2SO4
6
KNO3
6-7
Ca(NO3)2
6-7
NH4CO3
8 or 9
NH4Cl
11
(NH4)2SO4
5-6
CaCO3
7-9
MgCO3
8
CH3CO2Na
7 or 8
Physical Property Test: Unknown had granular properties, very white. Looked like cane sugar. The smell test indicated no odor.
Precipitate Test: this test indicated that Calcium Nitrate (Ca(NO3)2 and Calcium Chloride (CaCl2) are precipitates of the unknown. It was shown by a diluted, white bottom in the test tube.
Temperature: The solution wasn’t mixed well enough so the compound hardened in the bottom of the beaker, but once the solution was heated the hardened compound had a phase change and it completely dissolved in the water. The solution of Sodium Sulfate had the same reaction.4
Precipitation to Reaction: The Hydrochloride and Calcium Carbonate Solution was mixed with the unknown and the sodium sulfate and it reacted to create a precipitate, so it can be deducted that HCL and Calcium Carbonate was precipitated to Sodium Sulfate and the unknown.5
Discussion
During the experiment, it was very hard to have an explicit procedure since there was a lot of deviating from the plan and doing experiments so it was certain what the unknown sample was actually Sodium Sulfate. With high certainty it can be said that because the second week’s reaction were both the same, the unknown was Sodium Sulfate. One observation that was noticed during the solubility and the temperature test that even though the compound was soluble in water, if there was too much of the compound, not all would dissolve. This would leave a hardened version of the compound in the bottom of the beaker. The main observation that was noticed was the fact that once the solution was heat up, the hardened compound at the bottom of the beaker dissolved. This is because compounds become more soluble in higher temperatures.1 It is not hard to interpret the results of this project just because it is very explicit and it is very certain that the unknown substance was indeed Sodium Sulfate, but the tests that were done help give a rationale of the decision that the unknown was Sodium Sulfate the chemical equations make it more certain. The precipitate reaction of, Ca(NO3)2 (aq)+ Na2SO4 (aq)→ CaSO4 (s) +(NO3)2Na2(aq), explains the reaction system of Calcium Nitrate and Sodium Sulfate. The precipitate in that reaction ended up being the Calcium Sulfate.3 This is important because when two solutions mix, the precipitate can be found by writing down the chemical reaction. The solubility test showed the same results with empirical data. Na2SO4 (s) + H2O→ Na2 (aq) + SO4 (aq) + H2O, the solid compound reacted with the water and phased changed into a liquid, this dissolving process is important because not all compounds dissolve in water and it further exemplified how Sodium Sulfate is the unknown. The explicit data from the chemical equations aids in the identification of the unknown because the unknown had the same precipitate as the known Sodium Sulfate. If there were more variables, it would be harder and there would need to be more explanation for the results that were collected.
Conclusion
Based on all the experiments that were done, it is easy to say that the unknown white compound is Sodium Sulfate. All the tests that were done on the unknown showed the same properties as Sodium Sulfate. It is important the reBased on the information the MSDS for the compound says that there could be skin irritation and it could cause vomiting if ingested.6 To synthesize Sodium Sulfate is very dangerous to synthesize because one of the reactants is Sulphuric Acid and that is a dangerous acid. The products of the reaction end up being Na2SO4+10H2O, while the reactants are H2SO4+ Na. This compound is used in detergents and in the process of paper pulping.7
References
White Paper. Solubility: Importance, Measurements, and Application. www.crystallizationsystems.com (accessed Oct. 17 2017)
Prolom Water. The Significance of the pH Value. http://prolomvoda.com/prolom_water.php?pro_id=23 (accessed Oct. 17, 2017)
Chemistry Libre Texts. Precipitation Reactions. https://chem.libretexts.org (accessed Oct. 17, 2017)
Lab Archives. Data and Notes Project 3 Rushil and Miranda. www.labarchives.com (accessed Oct. 17, 2017)
Lab Archives. Data and Notes Project 3 Kau Boayue. www.labarchives.com (accessed Oct. 17, 2017)
Science Lab. Material Safety Data Sheet for Sodium Sulfate. http://www.sciencelab.com/msds.php?msdsId=9927278 (accessed Oct. 17, 2017)
General Chemistry. Sodium Sulfate. www.vias.org/genchem/inorgcomp_sodiumsulfate.html (accessed Oct. 17, 2017)