Measure the time it takes to completely dissolve. Record time in data table. Cold Water: Fill beaker with 80mL if ice water. Use thermometer to record temperature of water. Record the temperature.
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.
Check if the milk has clotted in each test tube by removing the test tubes from the water and tilting slightly every 30seconds. If the milk has clotted it should not move. 9. Record the time taken for the milk to solidify completely for each test tube in the results table. Results: Groups | 0-10degrees | 35-40degrees | 80-90degrees | 1 | NR | 2.35 | NR | 2 | NR | 3.30 | NR | 3 | NR | 2.28 | NR | 4 | NR | 1.40 | NR | 5 | NR | 5.30 | NR | Discussion: Temperature affects the rate at which molecules collide with each other.
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. Then, centrifuge it for 1 minute. On the side, weight a boiling test tube containing 2 boiling chips. When the separation is complete, remove the small test tubes from the centrifuge and decant the supernatant into the boiling test tube. Add 1 mL of deionized water to the small test tube containing the precipitate and mix it and centrifuge it for 60 seconds.
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.
When the pipet was half emptied into the ice water a timer was started. This aliquot was the first sample taken at t=0. The sample was rapidly titrated with 0.100 M HCl to a phenolphthalein endpoint and the final volume was
Food should be thrown out or refrigerated after being left out for 2 hours. All reheated food should be heated to 140 degrees F. Make sure you practice good hygiene, by washing your hands, washing utensils before using again, heating properly and storing properly. 1.3 Personal protective clothing (ppe) should be worn when handling food to prevent the spread of germs or bacteria for example if you have a small cut on your hand it could get infected or you could spread infection onto the food therefore spreading to the service user. Using aprons will protect your clothing from becoming dirty but also prevent any bacteria on your clothing spreading onto surfaces and the food you are preparing. Gloves and aprons will also protect your skin from burns from oils, very hot liquids and food containers.
Care must be taken when squeezing the pipet bulb on the filter pipet. Too much pressure might cause the filter to leak or fall off. Add about 2 mL of fresh tert-butyl methyl ether to the solid in the RB flask, warm briefly, let the solids settle for a minute, and pipet the liquid to the centrifuge tube as before. Again allow the solids to settle briefly in the centrifuge tube, then filter the liquid through the pressure filtration apparatus, into the same 25 mL Erlenmeyer flask. Doing a rinse such as this helps to ensure that any trimyristin that was left behind in the RB flask and centrifuge tube is not lost, thereby helping to ensure that
UNCW Honors Chemistry Lab #1- Laboratory Safety and Boiling Water Date Started: 8/26/11__________________ Date Completed __________________ Purpose: To determine the temperature at which water boils. To learn how boiling and melting are physical changes. Background Information/Observations: 1) Explain the most common scenario when you observe water boiling. 2) Explain how you could change the rate at which water boils. 3) Explain how you could change the temperature at which water boils.
Part 1: Scemario 4 Carmen conducted an experiment to determine whether salt added to a cup of water affects its freezing point (the temperature at which it freezes). After some research, she hypothesized that the greater the amount of salt dissolved in the water, the lower the temperature at which the water freezes. Water samples were prepared containing equal quantities of water at the same starting temperature. Each sample received a different amount of salt and was placed into a freezer. The length of time it took for each sample to freeze was recorded as shown below.