After a small amount of time the solution began to produce gas and the copper was being used up in the reaction. The solution turned an aqua like blue and eventually all of the copper had now been used into this blue solution which was copper nitrate and water, the gas being produced was nitrogen dioxide and the fume hood had removed it during the reaction. Next we slowly added drops of 6 molar sodium hydroxide to the solution until it became basic and turned a red piece of litmus paper blue. While we added NaOH the solution turned green indicating a new reaction had occurred and turned the litmus paper blue. We then began to heat and stir the solution until it changed color again and it turned black with a layer of water on top.
The watch glass was removed with the beaker tongs. Using a rubber bulb and a stirring rod to stir the solution continuously, 15.00mL of .25M BaCl2 solution was added to the solution in the beaker. The watch glass is replaced and the solution is keep hot but not boiling for 15 minutes. The precipitate was allowed to settle. When the liquid above the precipitate was clear, the solution was tested for completeness of precipitation when a few drops of BaCl2 solution were added from a pipette.
12. Place a paper towel over the drain, pour the content of the well plate, throw the paper towel and rinse the well plate. DATA, OBSERVATIONS, AND CALCULATIONS: Data Table: Oxidation - Reduction | | Reactions | Mg in Na2SO4 | Bubbles | Zn in MgSO4 | Small bubbles | Pb in Zn(NO3)2 | Dark lead changed into lighter color | Pb in FeCl3 | Changed the lead into slight green yellow | Fe in CuSO4 | Changed the iron into orange color | Note: I added more than 10 drops to make sure that the pieces are well covered. QUESTIONS: A. Based on your observations make an activity series of the metals used.
| 3 drops of 1% dimethylglyoxime solution. | [Ni(NH3)6]2+ + 2H2DMG→ Ni(HDMG)2 + 2NH4+ + 4NH3 | 9 Al3+ | By heating the solution in the hot water bath. | A black gelatinous precipitate was changed to colorless. | 6M NH3 | [Al(OH)4]- + 4H+ → Al3+ + 4H2O | 10 | Centrifuge the solution. | Colorless solution.
Allow the mixture to cool for a few minutes then filter it, using either gravity or vacuum filtration. (We shall be using vacuum filtration.) Wash the residue in the funnel once with a little water and collect all the filtrate. 4. Pour all the filtrate and washings into a 250cm3 volumetric flask.
The MgSo4 absorbed the last traces of water the ether solution. The solution was completely dry when it appeared crystal clear and MgSO4 floated in the liquid, when swirled. If solution is cloudy, more drops of MgSO4 were to be added until solution was completely dropped. 5) We decanted the solution from the solid MgSO4 into a 50 or 100 ml round bottom flask. 6) The ether was removed using the rotary evaporator.
HCl is carefully dropped into the Erlenmeyer flasks with the primed pipette until the solution turn to a green tint. Once the green tint has been achieved, drop one or two more drops of HCl to the solutions until the tint turns yellow. The flask is heated until all of the
As the drops are being added, a distinct yellow color can be observed where the drops were landing in the solution. The solution then turned blue-green and very cloudy when about 50 drops of NH3 were added. A distinct dark blue color was evident where the drops were landing in the solution. Also, there was an emission of gas while the NH3 was being added. Another change of color and clarity is evident when 15.0mL of H2SO4 was added to the
4. Chlorine, Cl 2, is a strong oxidizing agent found in bleach. 10.0 cm3 of bleach solution was added to 25.0 cm3 of 0.4M Sn2+ solution acidified with sulphuric acid and made up to 100 cm3. 10.0 cm3 of the resulting solution containing the unreacted Sn2+ was titrated against 0.02M K2Cr2O7. Given that 11.40 cm3 of K2Cr2O7 was required for complete oxidation, a) Calculate the numbers of moles of Cr2O7- used.
When in flame it produces gas rapidly and bubbles. Liquid turns into gas quickly. When liquid disappears solution (now a solid) turns white | 4 | A Initial temperature is 15 degrees Celsius and the final temperature is 17 degrees Celsius. BThe blue hydrated copper sulphate turned white, evidence of condensation of a clear liquid present on the inside of the test tube.C concentrated sulphuric acid turns black on paper towel and is clear on the white cottonD Carbon pillar grows cause of air bubbles, it is brittle, it is both corrosive with a hole and there is evidence of carbon produced | 5 | No temperature change and iodine brown/yellow gas produced | Properties of Sulphuric acid results table Aim: To investigate and observe the properties of sulphuric acid through five different experiments where we will determine its extent of ionisation in aqueous solution, reaction of sulfate ions, action as a strong acid, affinity for water and action as an oxidising agent. Background: Sulfuric acid (H2SO4) is a diprotic acid (can donate 2 protons to a base).