For every 20 drops of solution you will add 0.1g of zinc to the new test tube. Repeat steps 3 and four until the solution is clear. If there ever exists too little of the solution to get enough drops, add up to 1mL of distilled water to the solution. 4. Once the solution is clear, retrieve at least ten drops of the solution and place them in a new test tube.
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.
Data: Data Table 1 | | | Rubbing Alcohol Trial # | Boiling Point | Percent Error | 1 | 79.5 C | 3.52% | 2 | 84.0 C | 1.90% | 3 | 83.5 C | 1.30% | Data Table 2 | | | | Acetamide Trial # | Melting Point | Freezing Point | Percent Error (Melting Point) | 1 | 79.5 C | 57.5 C | 3.50% | 2 | 80.5 C | 59.5 C | 0.60% | 3 | 78.0 C | 61.0 C | 3.70% | Observations: It was observed that thermometer placement could affect the readings in the water bath. I ended up holding the test tube assembly to where the bottom of the test tube was not touching the bottom of the beaker to ensure better readings. Also, when substances recrystallize, I am not sure whether to take a reading when the substance has full crystallized or begun to so results could be fairly inaccurate. Questions: A. Why is it useful
Cool the beaker in ice water for 10 min, with stirring, and collect the solid by vacuum filtration on a small Hirsch funnel. Rinse with three small portions of water, by breaking the vacuum, adding just enough water to cover the solid, and reapplying the vacuum as before. Filtration of the fine crystals is slow. Using too much rinse water will slow the process considerably. Allow the solid to dry at least overnight, weigh it, take a MP, and calculate the % yield.
Fill the burette with 0.005mol dm-3 potassium manganate(VII) solution. 6. Pour some of the thyme extract solution into a 250cm3 plastic beaker. 7. Using a measuring cylinder, add 50cm3 of 1.0mol dm-3 sulphuric(VI) acid to the thyme extract in the conical flask.
Then 5mL of HCl was added to copper to completely remove all traces of zinc. Once the bubbling had stopped, the rest of the liquid was decanted away from the copper. Then the copper recovery set up was put together using tubing, Buchner funnel, filter paper and suction flask. Then the filter paper was weighed before placing it in the funnel and wetted down. The aspirator was turned to medium high, and then the copper was poured onto wetted filter paper.
Gracen Seiler April 7th, 2015 Section- 109 Investigating Stoichiometry with Sodium Salts of Carbonic Acid Introduction- This experiment is intended to help find a better understanding of chemical stoichiometry through titrations of NaHCO3 and NA2CO3 with HCl. A chemical reaction is a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form in a nuclear reaction. Titration is when a measured amount of solution of unknown volume is added to a known volume of a second solution until the reaction between them is complete. The objective of this experiment is reacting sodium bicarbonate (NaHCO3) and sodium carbonate (NaCO3) with hydrochloric acid (HCl) to produce sodium chloride (NaCl), water (H20) and carbon dioxide (CO2). -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”.
Because this reaction is reversible, a fractional distillation is necessary to produce cyclohexene, water, and some impurities and a simple distillation is followed to further purify the product. [pic] (Fig. 1- Cyclohexanol dehydrated by sulfuric acid to produce cyclohexene) Procedure: 1. Mix five mL of Cyclohexanol and 2.5 mL of 9M sulfuric acid in a 25 mL flask. 2.
Investigating the Chemical Composition of Alka Selzter Problem: How much sodium bicarbonate is in a tablet of Alka Seltzer? Purpose: To discover the amount of sodium bicarbonate, in grams, in a one tablet of Alka Seltzer. Materials: one Alka Seltzer tablet 50 mL of vinegar post-it note Triple beam balance beaker Procedure: 1) Put the post-it on the triple beam balance and zero the balance. 2) Measure the masses of the alka-seltzer tablet, and the beaker + vinegar. Record them.
Bring the contents of the distillation flask to a gentle reflux (i.e., vapors are condensing in the first ¼ to 1/3 of the vertical condenser and dripping constantly back into the flask below). Maintain this reflux for 10 minutes, then increase the heat in order to distill the liquid into the collection flask, then the column, and even the distillation head with aluminum foil (shiny side IN). Continue distillation of the cyclohexene product until the volume in the distillation flask is reduced to about 1 mL. Ask the instructor to assist you in removing the heat source and sand bath for the almost empty flask; use Ove Gloves and/or clamps to avoid burns. |