Transcript
SAFE WORK PROCEDURE LOCATION VMC
WRITTEN BY: APPROVED BY: Science Team
Heating and Cooling Curves Page 1 of 2
DATE CREATED
WS&H
LAST REVISION
June 27, 2014
New
PERSONAL PROTECTION EQUIPMENT (PPE) Safety glasses or face shield must be worn at all times in work areas.
Long and loose hair must be tied back
Appropriate footwear must be worn. Shoe must be fully enclosed. No open toed shoes.
Close fitting/protective clothing must be worn. Remove strings hanging from pullovers/sweaters.
Rings and jewelry (long necklaces / bracelets, etc.) must not be worn.
HAZARDS PRESENT
Chemical burns Absorption of Chemicals. Inhalation of Chemicals. Ingestion of Chemicals. Slips / trips & falls Chemical hazards Burns from the Bunsen burner
ADDITIONAL REQUIREMENTS
APPARATUS / MATERIALS
Test tube and cork Beaker Thermometer Ring stand Iron ring Test tube rack Wire gauze Test tube clamp Bunsen burner Stop watch Blue pencil Red pencil Lauric acid Water
Equipment orientation WHMIS training
SAFE WORK PROCEDURE 1. Don all personal protective equipment including: safety glasses, & protective nitrile gloves (where required). Ensure all loose clothing is either removed or tied back. Remove any jewelry and tie back long hair. 2. Heat the lauric acid slowly and carefully to avoid “popping”, and avoid inhaling any vapours that may be released during heating. Be careful when using the thermometer to stir the sample. Immediately report any breakage to your teacher. Tie back long hair and secure loose clothing when working with an open flame. Note the safety alert symbols here and with certain steps in the procedure. Always wear safety goggles and a lab apron or coat. 3. Fill a 250 ml beaker three quarters full of cold tap water. 4. Obtain a corked test tube containing a sample of the lauric acid. Clamp the test tube to a ring stand.
SAFE WORK PROCEDURE
Heating and Cooling Curves Page 2 of 2
5. Remove the cork and heat the sample carefully by moving the burner gently back and forth. Caution: Before heating, check to see that the mouth of the test tube is pointing away from yourself and others. 6. As soon as the sample begins to melt, remove the heat and place a thermometer in the sample. Using the thermometer to stir the sample, resume heating gently until the sample is completely melted. Do not overheat. At this point, record the temperature every ½ minute on your data table. 7. When the temperature of the sample is 60°C, set the time at 0 minutes. Immediately immerse the test tube into the cold water bath, making sure the entire sample is below the surface of the water. 8. The recording partner will call out the time every ½ minute. The second partner will use the thermometer to stir the sample constantly as long as some liquid remains. 9. Continue until you reach 25 °C. Remove the test tube from the water and stand it in a test tube rack 10. Heat the water in the beaker to a temperature of about 70°C. Remove the heat. 11. While the water was being heated, the sample in the test tube was cooling to approximately room temperature. Set the time at 0 minutes when you record the exact temperature of the sample and immerse it below the water level in the hot water bath. Read and record the temperature every ½ minute. 12. As soon as the thermometer is free to move, it should be used to stir the solid-liquid mixture. Continue stirring and recording the temperature at half-minute intervals until the temperature of the sample reaches 50°C. 13. Remove the thermometer and clean it. Remove the test tube from the water bath and allow it to cool. Replace the cork in the test tube and return the sample to your teacher. 14. Clean up your workstation. REGULATORY REQUIREMENTS
WS&H Act W210, Section 4, 5 Mb. Regulations 217/2006, Part 16, (Machines / Tools & Robots) Sections 16.1-16.18) Part 35, (WHMIS Application) Part 36, (Chemical & Biological Substances Application)
