A graph for the data was also set up with time on the x axis in .5 second intervals and temperature on the y axis. The first task required the freezing point of pure p-xylene be determined. This was done by pipetting approximately 2ml of p-xylene into a polypropylene test tube. The dry thermistor probe was inserted into the p-xylene test tube which was then inserted into an ice water bath. The temperature probe was used to stir the p-xylene and ensured an accurate reading.
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.
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
Literature review: I have chosen two online paper towel experiments. The first one is called The Paper Towel Experiment (Mr. Salsich, 2011). In this experiment their hypothesis was to see if the more expensive paper towels absorb more than the cheaper brands by folding them and inserting into water and using a stop watch. Their results were that all the paper towels absorb averagely. In the second experiment called Soggy Paper (Martyn Shuttleworth, 2008) they used four different paper towels to see which one soaked up the water more.
Both flask’s pH went up 4. Which substance, water or the buffer does a better job of maintaining pH when small amounts of strong base are added? Water does a better job at maintaining pH under these circumstances, but only slightly 5. Write equations for the reactions taking place in each of the flasks. For an equilibrium arrow ( ) is an equals sign (=) (Unless you know how to do equilibrium arrows).
Abstract In this experiment we are explored the simple calorimetric estimate for the enthalpy of combustion of different alcohols. Our aim is to find out which alcohol is most efficient. Method First of all we drew up a table – this was what we used to record our results in. We then measured 100cm3 of water into a measuring cylinder and poured the water into steel we then recorded its temperature. We selected a spirit burner and recorded the name of the fuel into our table; we also included the mass of the whole burner.
Do an initial Benedict's test on the 15% glucose/1% starch and the beaker solutions for glucose by putting some of the solution and a roughly equal amount of blue Benedict's solution in a test tube, placing the test tube in boiling water for 90 seconds, and observing whether or not the solution changes color from blue. 3. Form a bag out of dialysis tubing by tying off one end, putting in enough 15% glucose/1% starch solution to fill it halfway, and tying off the other end leaving the other half of the bag void of anything (even air). Write down the solution's color. 4.
* 12.00 mL of the K2CRO4 solution was slowly poured into the beaker containing the Pb(NO3)2Vsolution while stirring the Pb(NO3)2 solution. * The K2CrO4 beaker is rinsed with 10 mL of 5% nitric acid solution and added into the beaker. * The beaker is heated on a hot plate in the hood for 2-3 min. * Our professor demonstrated the correct filtration technique. * The mass of a piece of filter paper is determined to the nearest milligram.
Another source of rennin is junket tablets, which are used in setting milk into a solid junket or dessert. Junket tablets are used as a source of rennin in this experiment. Materials (per group) (This experiment may be done in groups of four. Each student can look after two temperature set-ups.) » 2 Bunsen burners »2 tripods » 2 wire gauzes » 2 × 150 mL beakers » 2 × 250 mL beakers for 70°C and 80°C water baths » 5 Styrofoam cups for unheated water baths » 8 thermometers 0–100°C » 16 test tubes in a rack » 10 mL measuring cylinder » junket tablet » 50 mL milk » Crushed ice » dropper » plastic spoon » marking pen » Distilled water Note: Thermostatically controlled water baths may be used if available.
Compare the MPs of the once recrystallized and the twice recrystallized trimyristin. After the hydrolysis has proceeded for 45 minutes, allow the flask to cool to RT and pour the contents into a 50 mL beaker containing 8 mL of water. Carefully, in the hood, add dropwise with stirring, 2 mL of concentrated HCl (caution: corrosive liquid/noxious vapors). Myristic acid should precipitate. Cool the beaker in ice water for 10 min, with stirring, and collect the solid by vacuum filtration on a small Hirsch funnel.