The purpose of the first part of this experiment was to determine which unknown cations were in the given metal nitrate salt solution using qualitative analysis. Quantitative analysis involves a numeric measurement of a species, and qualitative analysis (the method used in the experiment) involves the identification of a species. In part A, the solution was analyzed for lead or silver and calcium or barium in part B. In part A, silver was present in the solution, and in part B, calcium was present in the solution.
In part A, a strong acid, HCl, was added to the solution. HCl is a strong acid because it completely dissociates in a solution, therefore, it is highly reactive. The negative Cl- ions reacted with the positive metal cations in the
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A white, powdery appearing precipitate of either BaCO3 or CaCO3 formed in the bottom of the test tube, and the precipitate was washed and the liquid was discarded. Acetic acid was added to the precipitate and was mixed until all of the precipitate dissolved, and then DI water was added. After the solution was no longer cloudy, NH4OH and K2CrO4 were added to the clear liquid and mixed thoroughly and centrifuged. Potassium chromate was added in step 12 because barium reacts with the chromate ion to form a yellow barium chromate solid.2 The resulting dark orange liquid was decanted into a test tube labeled “step 14.” The solid precipitate was analyzed for the presence of barium by dissolving it in HCl, decanting the resulting liquid, and adding H2SO4 to that liquid. No precipitate formed, so the solution was then tested for the presence of calcium. A false positive (the finding of a result that is not accurate) may have occurred if the solution was still cloudy when NH4OH and K2CrO4 were added. The cloudiness of the liquid indicated that the precipitate which could have been BaCO3 or CaCO3 did not fully dissolve, so it could have lead to the presence of a white precipitate in step 13 that did not contain barium. (**Unfortunately, while cleaning up from the previous steps, we discarded the “step 14” test tube, so we watched another group that had calcium in …show more content…
[Ag(NH3)2]+ (aq) + Cl– (aq) + 2H+ (aq) ⇌ AgCl (s) + 2NH4+ (aq) net ionic
[Ag(NH3)2]Cl(aq) + 2 HNO3(aq) ⇌ 2 NH4NO3(aq) + AgCl(s) total
In part B, the presence of Ca2+ was confirmed.
Ca2+(aq) + (C2O4)2-(aq) ⇌ CaC2O4(s) net ionic
CaCl2(aq) + K2CrO4(aq) ⇌ CaC2O4(s) + 2KCl(aq) total
Centrifuges were utilized in the lab to separate substances of different densities (i.e. liquid solution and precipitate). Centrifuges separate solids and liquids so quickly because they use high rotational velocity, causing the denser solids to move toward the outer wall of the centrifuge and bottom of the test tube.3 It is vital to balance the centrifuge because the tubes are spun at high rotational velocities, so an imbalance of mass can cause a failure of the centrifuge to work properly and a possible safety
The purpose for this experiment was to determine why it was not possible to obtain a high percent yield when Calcium Nitrate Ca(〖NO_3)〗_2 with a concentration of 0.101 M was mixed with Potassium Iodate KIO_3 with concentration of 0.100 M at varying volumes yielding Calcium Iodate precipitate and Potassium Nitrate. Filtration was used to filter the precipitates of the solutions. The percent yield for solution 1 was 87.7%, and the percent yield for solution 2 was 70.8%. It was not possible to obtain a high percent yield because Calcium Iodate is not completely soluble and some of the precipitates might have been rinsed back to the filtrates when ethanol was used to remove water molecules in the precipitate.
The purpose for this lab was to use aluminum from a soda can to form a chemical compound known as hydrated potassium aluminum sulfate. In the lab aluminum waste were dissolved in KOH or potassium sulfide to form a complex alum. The solution was then filtered through gravity filtration to remove any solid material. 25 mLs of sulfuric acid was then added while gently boiling the solution resulting in crystals forming after cooling in an ice bath. The product was then collected and filter through vacuum filtration. Lastly, crystals were collected and weighed on a scale.
The purpose of the Unknown White Compound Lab was to identify the unknown compound by performing several experiments. Conducting a solubility test, flame test, pH paper test, ion test, pH probe test, conductivity probe test, and synthesizing the compound will accurately identified the unknown compound. In order to narrow down the possible compounds, the solubility test was used to determine that the compound was soluble in water. Next, the flame test was used to compare the unknown compound to other known compounds such as potassium chloride, sodium chloride, and calcium carbonate. The flame test concluded that the cation in the unknown compound was potassium. Following, pH paper was used to determine the compound to be neutral and slightly
At this point the identity of the unknown compound was hypothesized to be calcium nitrate. In order to test this hypothesis, both the unknown compound and known compound were reacted with five different compounds and the results of those reactions were compared. It was important to compare the known and unknown compounds quantitatively as well to ensure that they were indeed the same compound. This was accomplished by reacting them both with a third compound which would produce an insoluble salt that could be filte...
CL-, as the ions of H+ and OH- react to form H2O. These spectator ions
Based on our observations during the separation techniques and some speculation, we were able to identify eight components of our mixture: graphite from the filtration residue, Epsom salt from crystallization, water and acetic acid through distillation, red and orange dye, iron metal, marble chips, and sand.
In this case, the nitrate ion moved from one compound to another as the Cu was replaced by Zn. The zinc dissolved to form zinc (II) ions as the copper (II) ions came out of the solution as copper metal and deposited on the surface of the
Barium is a soft, heavy, silver-colored metal element. This element does not have very many uses outside of the laboratory, but it combines easily with other chemicals to form compounds used for important industrial uses. For example, Barium carbonate is used in the manufacture of ceramics and special glass, and also to purify certain chemical solutions. It is also an ingredient in clay slurries, also known as water muds, used in drilling oil wells. Barium titanate is used in sonar detectors and other electrical equipment. At low doses, barium acts as a muscle stimulant and at higher doses affects the nervous system eventually leading to paralysis. Acute and subchronic oral doses of barium cause vomiting and diarrhea, followed by decreased heart rate and elevated blood pressure. Higher doses result in cardiac irregularities, weakness, tremors, anxiety, and dyspnea. A drop in serum potassium may account for some of the symptoms. Death can occur from cardiac and respiratory failure. Acute doses around 0.8 grams can be fatal to humans. Barium nitrate makes signal flares burn with a green flame. Barium ferrite is used to make magnets. Barium sulfate is an extremely insoluble barium compound that is not poisonous. Doctors use it in X-ray examinations of a patient's digestive system. The barium sulfate absorbs X rays to show an outline of the intestines on the developed film. A barium enema is performed to examine the walls of the colon. During the procedure, a well lubricated enema tube is inserted gently into the rectum. The barium is then allowed to flow into the colon. The flow of the barium is monitored by the health care provider on an X-ray fluoroscope screen. The test is used to detect colon cancer. The barium enema may also be used to diagnose and evaluate the extent of inflammatory bowel diseases. Barium sulfate and zinc sulfide form lithopone, a white coloring matter for paint. Barium is never found in a pure state because it combines so easily with other elements. Pure barium is obtained by passing an electric current through a fused barium compound, such as barium chloride. A piece of barium metal quickly reacts with oxygen and water vapor in the air to form barium oxide. It must be stored under kerosene to keep it pure. Barium is found most often as barium sulfate in the mineral barite. The chemical symbol for barium is Ba.
Solid A was identified to be sodium chloride, solid B was identified to be sucrose, and Solid C was identified to be corn starch. Within the Information Chart – Mystery White Solid Lab there are results that distinguishes itself from the other 4 experimental results within each test. Such as: the high conductivity and high melting point of sodium chloride, and the iodine reaction of corn starch. Solid A is an ionic compound due to its high melting point and high electrical conductivity (7), within the Information Chart – Mystery White Solid Lab there is only one ionic compound which is sodium chloride, with the test results of Solid A, it can be concluded that is a sodium chloride. Solid B was identified as sucrose due to its low electrical
The metal Ni2+ and the ligand ethylenediamine (en) are studied in this experiment. Solutions are prepared with varying compositions of Ni(en)n2+. Using the equilibrium constants, it is possible to identify which species is present. If the constant for the formation of a species where n is 2 is larger than a species whose constant equals 3 then the former species is pre-dominant. Jobfs Method is limited in that it will give non-integral values of the n present if a fourth complex, ZLn+1, exists. If there is a large variation between the equilibrium constants then only two complexes will be present in the prepared solutions. The absorbance values are plotted, then the value of n can be calculated.
Cl- (aq) + Na+ (aq) + OH- (aq) Na+ (aq) + Cl- (aq) +H+ + OH- [IMAGE]The above is an example of a neutralization reaction, involving an acid and an alkali. The result is a salt and water. In every neutralization reaction, the metal in the alkali (Na+ here) takes the place oh the hydrogen in the acid, forming a metal compound called a salt.
== = == Hypothesis for the experiment: After I conduct this experiment, I expect and suppose I can recognize and physical changes, identifying the difference these two kinds of changes. Also, I will be able to know some physical and chemical properties of copper (II) sulfate, water, iron, sodium carbonate, hydrochloric acid and magnesium and identify if it is a chemical change or physical change in each part of the experiment.
A complexometric titration takes place in an aqueous sample inorder to displace water from the ion. As the metal ion will be ionated once in solution therefore, empty valence empty shells are achieved [1]
1. The labels have fallen off of three bottles thought to contain hydrochloric acid, or sodium chloride solution, or sodium hydroxide solution. Describe a simple experiment which would allow you to determine which bottle contains which solution.
In this experiment three different equations were used and they are the Stoichiometry of Titration Reaction, Converting mL to L, and Calculating the Molarity of NaOH and HCl (Lab Guide pg. 142 and 143).