In this step, as we watched the chemical reaction with the solids, we noticed a thinning in the substance. Also, the solids became lighter and moved to the top. When stirred, the solution began to turn green and then back to light blue, where copper began in the end of the first step. A combination reaction took place, and the balanced equation is: CuOs+H2SO4aq→CuSO4aq+H2O(I) Following this step, step 5 began, in which we added 300 mg of zinc to the solution. Once the zinc was added slowly to the solution, a gas was released and the solution began to change colors.
-Use the titrations of the following chemical reactions: NaHCO3 + HCl (aq) NaCl (aq) + H2O (l) + CO2 (g) 2HCl (aq) + Na2CO3 (s) 2NaCl (aq) + H2O (l) + CO2 (g) Experimental procedure- Two Erlenmeyer flask must be labeled “unknown 1 and unknown 2”. Assure that all containers used are dried and cleaned properly. Two bigger flask are labeled “waste” according to each unknown. A pipette is set up and primed with HCl. The two unknown solids are weighed to a mass of 0.15g each.
The 1mL of HCl was then transferred to one of the 50mL beakers turning the color of the solution to yellow. Another 100mL beaker was obtained and filled with 1.0 M NaOH and the pipet again was used to acquire 1mL of the 1.0 NaOH solution. The 1mL of NaOH was transported into one of the 50mL beakers turning the color of the solution blue. Using the pipet once more, 1mL of distilled water was added to the beaker that was still the color green.
After that, dissolve the sample in 2 mL of deionized water and shake the test tube for 1 to 1 ½ minutes to dissolve the solid. Place another dry test tube in a 50mL beaker and weigh it. Find a bottle of barium iodide and record the name and molar mass. Then, weight out either anhydrous barium iodide or barium iodide dehydrate into this test tube and dissolve is it in 2 mL of deionized water. Pour the contents of one of the test tubes into the other and a reaction should occur and you should see a white precipitate of barium sulfate form.
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.
Using a measuring cylinder, add 50cm3 of 1.0mol dm-3 sulphuric(VI) acid to the thyme extract in the conical flask. 8. Titrate the solution in the conical flask with the potassium manganate(VII) solution until a pale pink colour persists for 10 seconds. 9. Repeat the titration until there are two titres within 0.1cm3 of each other.
Approximately 20 drops of a .04% Bromothymol blue solution was then added to the beaker of the phosphate buffer. Using a clean 5 mL serological pipette, transfer 5 mL of the phosphate buffer and Bromothymol blue solution to each of three clean 150 mL beakers. Next, using the buret for HCl, add 1 mL of HCl to one of the three beakers, then label this beaker “Yellow”. Next use the buret for NaOH and add 1 mL of NaOH to another of the three beakers, and label this beaker “Blue”. Lastly add 1 mL of water using the buret for water to the last beaker, and label this beaker “Green”.
White precipitate shows the presence of chloride (Cl-). Chloride anion equation: HCl(aq) + AgNO3 (aq) → HNO3 (aq) + AgCl(s). The nitrate anion test involves cooling a mixture containing 1 mL of test solution and 3mL 18M H2SO4. 2mL is poured down the inner test tube side and the presence of a brown ring shows nitrate (NO3-) to be present. The carbonate anion test mixes 1 mL of test solution and drops of 6M HCl.
The following data were obtained when a sample of barium chloride hydrate was analyzed as described in the Procedure section. Calculate (a) the mass of the hydrate, (b) the mass of water lost during heating, and (c) the percent water in the hydrate. Mass of empty test tube 18.42 g Mass of test tube and hydrate (before heating) 20.75 g Mass of test tube and anhydrous salt (after heating) 20.41 g. Mass of the Hydrate is 2.33g. Loss (H2O) is 0.34g. Percent H2O in Hydrate is equal 0.34/2.33=14.6% 3.
Obtain a clean-dry test tube. Place 0.3g of the unknown substance in the test tube. Next, add 10mL of distilled water to the test tube. Mix with a stirring rod until unknown is dissolved. 2.