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.
A 125mL Erlenmeyer Flask was used to combine (15mL) of concentrated aqueous ammonia and ammonium chloride (0.0467mol, 2.49g). The mixture was stirred till fully dissolved. Colbalt (II) chloride hexahydrate was ground (6.2g) and added in small amounts to the stirring solution (0.0210mol, 5.2g). As the mixture continued to stir (4mL) of 30% hydrogen peroxide was added drop wise to yield a dark warm slurry. After the effervescence, (15mL) of concentrated HCl was added drop wise to the solution.
Pour all the filtrate and washings into a 250cm3 volumetric flask. Make up to 250cm3 with 1.0mol dm-3 sulphuric acid(VI) acid. Stopper the flask and invert several times to thoroughly mix the solution. 5. Fill the burette with 0.005mol dm-3 potassium manganate(VII) solution.
Using another 125-mL flask, 60-mL of 0.3622 M potassium hydroxide in ethanol was deposited. Both flasks were clamped in a temperature-controlled bath regulated at 50.0˚C. The solutions were then set in the temperature bath for ten minutes to equilibrate. An empty 250-mL Erlenmeyer flask was also clamped in the same water bath. In another flask 50-mL of ice water was deposited with three-drop phenolphthalein.
The two unknown solids are weighed to a mass of 0.15g each. The unknown solids are dropped carefully into the corresponding Erlenmeyer flask wit 50mL of distilled water. The solid in the water must be dissolved and afterwards add 10 drops of Bromecresol green to indicate the change of color when the solution has been titrated. The flask should start with a blue tint. HCl is carefully dropped into the Erlenmeyer flasks with the primed pipette until the solution turn to a green tint.
Gravimetric Determination of Sulfate Purpose The purpose of this lab is to determine the percentage of sulfate in the hydrate by precipitating the sulfate as barium sulfate. Materials Filler paper Sodium sulfate Graduated cylinder Bunsen burner Watch glass Beakers (250 mL, 400 mL) Rubber bulb Graduated pipette Beaker tongs Funnel Filter Paper Sodium Sulfate Drying oven Wash bottle Stirring rod Silver nitrate Hydrochloric acid Distilled water Small test tube Procedures First, .4861 grams of sodium sulfate was placed into a clean 400mL beaker. Exactly 200mL of water and 1mL of HCl was added to the same beaker. A watch glass was placed on the beaker and the solution was heated using the Bunsen burner to a gentle boil. The watch glass was removed with the beaker tongs.
The extraction process is when a solvent, dichloromethane (15mL) is added to the filtrate in a separatory funnel; the mixture is gently swirled together 3 times, and stopcock is released in between to vent the funnel. Dichloromethane (including the emulsion) is then drained from the bottom into a 50mL Erlenmeyer flask. Same extraction process is repeated on the same filtrate and the dichloromethane is, once again, let out to the same 50mL Erlenmeyer flask as before. The combined dichloromethane solution and water (20mL) is poured into a rinsed separatory funnel. Mixture is gently swirled and drained out into an Erlenmeyer flask.
APPARATUS: Burette (50 cmᶾ), Pipette (25 cmᶾ), two conical flasks (250 cmᶾ), two beakers (250 cmᶾ), funnel, wash bottle, retort stand, boss and clamp, evaporating dish, pipette filler, hot-plate. MATERIALS: Approximately 2.0 mol dmˉ³ hydrochloric acid, 1.0 mol dmˉ³ sodium hydroxide, methyl orange indicator. METHOD: 1. Firstly, the burette was rinsed with a little hydrochloric acid and filled up to just above the zero mark. 2.
The mass was recorded and transferred to a 50 ml beaker. 4 ml of 6 M HNO3 was added to the beaker containing the copper. For step 2, 10 ml of distilled water was added to the beaker. Then, 6 M NaOH was added to the solution (drop wise), until placing a drop of the solution on red litmus paper turned it blue. For step 3, the solution was heated with a hot plate.
This solution was added drop wise to the stirred ethanolic solution of benzophenone at room temperature. After all the sodium borohydride being added, the mixture was stirred for a further 10min. Meanwhile, ice water (10ml) was mixed with concentrated hydrochloric acid (1ml) in 50ml beaker. To this the mixture of sodium borohydride and benzophenone was poured slowly into the beaker. The precipitate was collected using suction filtration and washed with 2 x 5ml portions of water.