Using the decanted supernatant solution from the precipitation experiment, a wire loop was dipped into the solution. This loop was stuck in the flame from a Bunsen Burner and heated until a flame appeared. The presence of a bright yellow flame confirmed that Na+ was in attendance. Using a cobalt glass as a filter, the loop was examined and a violet flame was present, showing that K+ was also in the supernatant solution.
Testing for NH +
This test was carried out using the original solution to avoid contamination of ammonium salts from the other procedures. 0.1M NH4CL and DI water were added to a large well on
the micro drop tray before drops of 6M NaOH were added. A piece of red litmus paper was put on top of the well and covered with a watch glass. The appearance of an unmarked blue color, a direct result of the release of NH3 gas, on the paper confirmed the existence of NH4+. The experiment was repeated using seawater instead of the 0.1M
NH4CL and DI water combination.
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Quantitative
Pre-Gravimetric Set Up
Test tubes were obtained and labeled using a bl according to which test the sample was intended for Barium) and what depth the sample was obtained at or bottom).All the test tubes were put in a beaker and
an oven at 110˚C for half an hour to dry. Once dry th
removed and allowed to cool on a test tube rack, as
Figure 1: Test tube rack with test tubes
Figure 1, before being weighed and their weights rec
Silver Halides Gravimetric Analysis
The tests tubes labeled ‘Halides Top’ and ‘Halides Bottom’ were taken and 1mL of seawater was added to each. The test tubes were then weighed and their new weights recorded, before 6M Nitric Acid (HNO3) was added to each to acidify it. 0.1M Silver Nitrate (AgNO3) was introduced, causing a white precipitate to form. The solution was stirred with a glass rod and centrifuges for approximately a quarter of an hour. Once complete,
another series of drops of 0.1M AgNO3 were added to ensure complete precipitation and
the solution was recentrifuged for several minutes. The supernatant solution was decanted into a wast container and DI water was mixed into the precipitate to clean it. The solution was centrifuged, supernatant decanted, and rinsed with DI water once more before being centrifuged and the aqueous solution decanted for a final time. The test tubes were then returned to the beaker and placed back into the oven to dry for a week.
5. A second test tube was then filled with water and placed in a test
The primary goal of this laboratory project was to identify an unknown compound and determine its chemical and physical properties. First the appearance, odor, solubility, and conductivity of the compound were observed and measured so that they could be compared to those of known compounds. Then the cation present in the compound was identified using the flame test. The identity of the anion present in the compound was deduced through a series of chemical tests (Cooper, 2009).
Experimental: The experimental procedure outlined in the OU Physical Chemistry Laboratory Manual was followed without any deviations.
Methodology: The experimenter used two ten gallon tanks. One tank will be used for the controlled group and the other tank will be used for the experimental group. Each tank will have two pounds of sand spread among the bottom of the tank along with rocks and artificial habitats to add nitrogen to the tanks. To add optimal living conditions for the oceanic life water filtration systems, temperature regulator, circulation systems, and a light to mimic the sun’s rays were added to each tank. At all times both tanks had a temperature of 75 degrees F. This experiment was done over a three month period. The first month was to allow the nitrogen cycle to occur. This allows the fish to be exposed to the water without having stress reactions due to unhealthy living conditions due to the nitrogen. Once the first month was complete six fish was added to both tanks. Two tangs, two damsels, and two clownfish. At first both tanks had a pH level of 8.2, ideal living conditions. After one week the experimental group was exposed to a pH level of 8.6. After two weeks it was raised to 9. Two weeks later it was raised to 9.3. The final raise was done two weeks after making the pH level 9.5. The final week of the experiment the pH lev...
The first step that we took to accomplish our goal was to put on our safety goggles and choose a lab station to work at. We received one 400ml beaker, one polyethylene pipet, two test tubes with hole rubber stoppers, two small pieces of magnesium (Mg), one thermometer and a vial of hydrochloric acid (HCl). We took the 400ml beaker and filled it about 2/3 full of water (H20) that was 18 OC. Then we measured our pieces of Mg at 1.5 cm and determined that their mass was 1.36*10-2 g. We filled the pipet 2/3 full of HCl and poured it into one of the test tubes. Then, we covered the HCl with just enough H2O so that no H2O would be displaced when the stopper was inserted. After inserting the stopper, we placed the Mg strip into the hole, inverted the test tube and placed it in the 400ml beaker. HCl is heavier than H2O, so it floated from the tube, into the bottom of the beaker, reacting with the Mg along the way to produce hydrogen gas (H2). We then measured the volume of the H2, cleaned up our equipment and performed the experiment a second time.
It is important however to note that the NH4 and K ions are still in
Experiment: First prepared a well plate with the appropriate amounts of distilled water, HCl, and Na2S2O3 in each well according to the lab manual. The well where the reaction
The procedure for this experiment can be found in Inorganic Chemistry Lab Manual prepared by Dr. Virgil Payne.
== § Test tubes X 11 § 0.10 molar dm -3 Copper (II) Sulphate solution § distilled water § egg albumen from 3 eggs. § Syringe X 12 § colorimeter § tripod § 100ml beaker § Bunsen burner § test tube holder § safety glasses § gloves § test tube pen § test tube method = == = =
== Refer to Chemistry Lab # 2 – Investigating Changes. No changes have been made in this experiment. Results = ==
The sample was subjected to steam distillation as illustrated in Figure 1. A total of 50ml of distillate was collected while recording the temperature for every 5.0 ml of distillate. The distillate was transferred into a 250ml Erlenmeyer flask and 3.0 g of NaCl was added. The flask was cooled and the content was transferred into a 250-ml separatory funnel. Then 25.0ml of hexane was added and the mixture was shaken for 5 minutes with occasional venting. The aqueous layer was discarded and the organic layer was left inside. About 25.0ml of 10% NaOH was then added and the mixture was shaken as before. The aqueous layer was collected and then cooled in an ice bath. It was then acidified with enough 6.00 M HCl while the pH is being monitored with red litmus paper. Another 25.0 ml of hexane was added and the mixture was shaken as before. The hexane extract was saved and a small amount of anhydrous sodium sulfate was added. The mixture was then swirled for a couple of minutes then filtered. A small amount of the final extracted was tested separately with 1% FeCl3 and Bayer’s reagent.
Richardson, S. Water Analysis: Emerging Containments and Current Issues. Journal of Analytical Chemistry. 2003, 75, 2831-2857.
There were five test solutions used in this experiment, water being the control, which were mixed with a yeast solution to cause fermentation. A 1ml pipetman was used to measure 1 ml of each of the test solutions and placed them in separated test tubes. The 1 ml pipetman was then used to take 1ml of the yeast solution, and placed 1ml of yeast into the five test tubes all containing 1 ml of the test solutions. A 1ml graduated pipette was placed separately in each of the test tubes and extracted 1ml of the solutions into it. Once the mixture was in the pipette, someone from the group placed a piece of parafilm securely on the open end of the pipette and upon completion removed the top part of the graduated pipette.
viii. The experiment could have been performed over one a longer period of time day (rather than 14 days), which would have greatly reduced any loss of water from the sodium hydroxide solution, which may have improved results slightly.
In this experiment the Sodium Hydroxide solution went through three different phases where its quality and quantity changed. The first phase was called I. Preparing Approximately 0.1M NaOH, 1000mL of clear distilled water was boiled and then chilled to room temp.