Zarqa University Laboratory Manual for Practical General Chemistry PDF

ZARQA UNIVERSITY Laboratory Manual for Practical General Chemistry 0300133 Faculty of SCIENCE Prepared by Intisar Ahmad Abou-sud 1  Laboratory Safety...

ZARQA UNIVERSITY Laboratory Manual for Practical General Chemistry 0300133 Faculty of SCIENCE Prepared by Intisar Ahmad Abou-sud 1  Laboratory Safety And Laboratory Guidelines The chemistry laboratory is one of the safest environments on campus or in an industrial setting. You will be doing many laboratory activities which require the use of hazardous chemicals. Every chemist, trained to be aware of the potential dangers of chemicals, is additionally careful in handling and storing chemicals. Safety in the science classroom is the #1 priority for students, teachers, and partners. To ensure a safe science classroom, a list of rules has been developed and provided to you in this student safety contract. These rules must be followed at all times. The chemistry laboratory is a safe place to experiment if you are careful. You, not the instructor, must assume responsibility of the safety of yourself and your neighbors. The following section presents some general guidelines to help guide you in protecting yourself and others from injury in the laboratory. These are not arbitrary rules set downs to make your life less enjoyable. A. Self-Protection: 1. Safety glasses, goggles, or eye shields must be worn at all times to guard against the laboratory accidents of others as well as your own. Eyes are extremely sensitive. 2. Contact lenses are not permitted in the lab. 2  3. To protect outer clothing, the wearing of laboratory aprons or coats must be donned at all the time. These aprons should be chemical and flame resistant. 4. Tie back long hair. Long hair can accidentally fall into flames or chemicals. Many hair sprays, gels, mousses, etc. are flammable! 5. No radios, tape players, CD players or any other devices of this type will be permitted in the lab. at any time. Loud music is distracting, and head phones prevent you from hearing announcement or verbal warning given in the lab. 6. Never taste, smell, or touch a chemical or solution unless specifically directed to do so. 7. All chemicals in the laboratory are to be considered dangerous. Avoid handling chemicals with fingers. Always use a tweezers. B. In Case of an Accident 1. Do not panic. The most important first action after an accident is the care of the individual. If a person is injured, provide or seek aid immediately; clothing and books can be replaced and experiments can be performed again later. Second, take the appropriate action regarding the accident; clean up the chemicals, use the fire extinguisher, and so on. 2. Even if the accident or injury is regarded as minor, notify your instructor immediately. 3. Wash your hands often during the lab. Always wash your hands, arms, and face before leaving the lab. Toxic or otherwise dangerous chemicals may be inadvertently transferred to the mouth. 4. Whenever your skin (hands, arms, face, …ect) comes into contact with chemicals, wash it quickly and thoroughly with soap and water. Use the eyewash fountain to flush chemicals from the eyes and face. Do not rub the affected area, especially the face or eyes, with your hands before washing. 5. Chemical spills over a large part of the body require immediate action. Using the safety shower, flood the affected area for at least 5 minutes. Remove all contaminated clothing if necessary. Use mild detergent and water if necessary. Get medical attention. 6. Treat chemical spills in the laboratory as follows:  Alert your neighbors and the laboratory instructor. 3   Clean up the spill as directed by the laboratory instructor.  If the substance is volatile, flammable, or toxic, warn every one of the accident. 7. For abrasions or cuts, flush the affected area with water. Any further treatment should be given only after consulting with laboratory instructor. For fire burns, place the affected area under running water for several minutes. 8. Know the locations and operating procedures of all safety equipment including the first aid kit, eyewash station, safety shower, spill kit, fire extinguisher, and fire blanket. Know where the fire alarm and the exits are located. C. Laboratory Rules: 1. Smoking, drinking, eating, and chewing gum are not permitted at any time because chemicals may enter the mouth or lungs. Your hands may be contaminated with unsafe chemicals. 2. When first entering a science room, do not touch any equipment, chemicals, or other materials in the laboratory area until you are instructed to do so. 3. Do not work in the laboratory alone. The instructor must be present. 4. Unauthorized experiments, including variations of those in the lab manual, are forbidden. 5. Maintain an orderly, clean laboratory desk and drawer. Immediately clean up all chemical spills, paper scrapes, and glassware. Discard wastes as directed by your laboratory instructor. 6. Keep the aisles free of any obstructions. Do not place book bags, athletic equipment, or other items on the floor near any laboratory bench. 7. At the end of laboratory period, completely clean the laboratory bench of equipment, cleans it with a damp paper, and clean the sinks of all debris. Also clean all glassware used in the experiment. 8. Be aware of your neighbors' activities; you may be a victim of their mistakes. Advise them of improper techniques or unsafe practices. If necessary, tell the instructor. 4 D. Working in the Laboratory: 1. Be in the laboratory and ready promptly when lab begin. The lecture will be the first item of business each day. If you are not present to get this important information you will not be allowed to do the experiment. 2. Maintain wholesome, businesslike attitude. Horseplay and other careless act are prohibited. 3. Do not entertain guests into the laboratory. 4. Prepare for each experiment by completing the pre-laboratory Assignment and by studying the objectives, introduction, techniques, and experimental procedure before laboratory. 5. Always try to understand the reason for each step and why you are doing it. 6. Review the laboratory questions at the conclusion of the report sheet before and as you perform the experiment. These questions are intended to enhance your understanding of the chemical principles on which the experiment is based. 7. Scientist learns much by discussion with one another. Likewise, you may profit by discussion with your laboratory instructor or classmates, but not copy from them. 8. Check the label on all chemical bottles twice before removing any of the contents. Take only as much chemical as you need. 9. Never return unused chemicals to their original container. 10.. Dispose of all chemical waste properly. Never mix chemicals in sink drains. Check with your teacher for disposal of chemicals and solutions. 11. At the end of the laboratory session see that: a) main gas outlet valve is shut off b) the water is turned off c) desk top, floor area, and sink are clean d) all equipment is cool, clean, and arranged. 5 E. Collecting Data: 1. Recall all data as they are being collected on the Report Sheet, not on scraps of paper. 2. Record the data in inks as you perform the experiment. 3. If a mistake is made in recording data, cross out the incorrect data entry with a single line (do not erase, white-out, or obliterate) and clearly enter the corrected data nearby. 4. For clarity, record data entries of values less than one with a zero in the "one" position of the number; for example, record the mass measurement as 0.345g rather than.345g 5. Believe in your data. A scientist's most priceless possession is integrity. Therefore, be a scientist. An incorrect answer resulting from honest work is infinitely better than a correct one obtained dishonorably. 6. For some experiments you will design your own Report Sheet; these report sheets must be planned and organized carefully. A thorough preview of the experiment will assist in your collection and presentation of data. Where calculations using data are involved, be orderly with the first set of data. Do not clutter the calculation section with arithmetic details. Safety equipments in the laboratory:  Safety goggles: Every student must wear these at all times in the lab. You must wear them even if you’ve finished your own experiments, because somebody else who is still working might have an accident that sprays your eyes with chemicals. THE ONLYEXCEPTION: If nobody is performing experiments at all (e. g. during exams and lectures), it isn’t necessary to wear them.  Lab coat: Every student must wear these at all times in the lab. Your lab coat is more than a symbol; it’s a layer of protection between you and laboratory hazards. 6   Fume hood: You will perform experiments that produce hazardous and smelly vapors in them. To save energy, keep the hood window closed when you’re not working directly on your apparatus.  Eyewash fountain: If you spill chemicals in your eyes, this is what you use. You may need help finding the eyewash fountain; don’t hesitate to call for it. Aim the spray into your eyes and wash them out for ten or fifteen minutes at least. It’ll be hard to open your eyes, but you must.  Safety shower: For use when you’ve spilled chemicals on yourself and your clothes. Stand under the shower and pull the metal triangle; floods of water will come down and wash you off. Lesser spills can be dealt with under the faucet, but in any case, use plenty of water.  Fire extinguisher: To operate, pick it up, pull the pin, aim the black cone at the base of the fire, and squeeze the handles. (You won’t be able to squeeze the handles together if you don’t pull the pin). HAZARDS WARNING SYMNOLS I.Flammable Flammable and Combustible Liquids (Examples: alcohols, esters, ethers, ketones) Vapors from flammable and combustible liquids can mix with air and burn if they contact an ignition source. Possible ignition sources include hot electrical wires, hot surfaces, open flames, hot particles, and sparks. 7 II.Corrosive Examples: Acids: Solids: benzoic acid Liquids: acetic acid, nitric acid, phenol, sulfuric acid; Gases: hydrogen chloride, hydrogen fluoride, hydrogen bromide, chlorine, and sulfur dioxide Bases: Solids: sodium, potassium and calcium hydroxides; Liquids: ammonium hydroxide, bromine; Gases: ammonia III.Toxic All chemicals should be considered toxic to some degree and should be handled with 8 caution. The level of toxicity (high, low, moderate) is based on dose-response measurements as performed on test animals. The term “toxic”, however must reference the route of entry for the material: inhalation, ingestion, skin contact, etc. IV.Explosive Examples: acetylides, azides, organic nitrates, nitro compounds, many peroxides, and perchlorates (e.g., ammonium perchlorate, picric acid, lead azide). VI. Irritant Examples: strong Acids and bases, volatile organic solvents like acetone and alcohol Laboratory Glassware and Apparatus Student should know the name and the use of different basic glassware and the apparatus used in the preparation of organic compounds. 9  COMMONLY ENCOUNTERED EQUIPMENT IN THE CHEMISTRY LABORATORY NAME PICTURE USE beaker Used to hold and heat liquids. Multipurpose and essential in the lab. brushes Used to easily clean the inside of a test tubes and other glassware. Buchner Used with vacuum flask for funnel performing vacuum filtration. Bunsen burner Used for heating and exposing items to flame. 10 burette Used in titrations to measure precisely how much liquid has been delivered. burette clamp Used to hold burettes on a ring stand. clay Used to hold crucibles when they triangle are being heated. They usually sit on a ring stand. crucible with lid Used to heat small quantities to very high temperatures. 11  crucible tong Used to hold crucibles and evaporating dishes when they are hot. disposable Used for moving small amounts of pipette liquid from place to place. They are usually made of plastic and are disposable electronic Used for weighing substances or balance objects, usually in grams. erlenmeyer Used to heat, mix, and store liquids. flasks The advantage to the Erlenmeyer Flask is that the bottom is wider than the top so it will heat quicker because of the greater surface area exposed to the heat. evaporating dish Used to recover dissolved solids by evaporation. 12  forceps Used for picking up and moving small objects. glass funnel Used to pour liquids into any container so they will not be lost or spilled. They are also used with folded filter paper for filtration. glass stir Used to stir liquids. They are rod usually made of glass. graduated cylinder Used to measure the volumes of liquids. hot plate Used for heating substances and liquids in beakers and flasks. mortar and pestle Used to crush solids into powders for experiments, usually to better dissolve the solids. 13 pipette with Used for accurately measuring and pump delivering small volumes of liquid- usually 0.1-10 mL. Attached to ring stand and with wire ring clamp gauze used to hold beakers or flasks while they are heated by a gas burner. ring stand Used to hold items being heated. Clamps or rings can be used so that items may be placed above the lab table for heating by Bunsen burners or other items. rubber Stoppers come in many different stopper sizes. The sizes are from 0 to 8. Stoppers can have holes for thermometers and for other probes that may be used. separatory funnel For separating layers of immiscible liquids or for dropping liquids. 14  spatula Used for moving small amounts of solid from place to place. striker Used to light a gas burner. test tube Used for storing, mixing, and heating small amounts of chemicals. test tube Used to hold test tubes while holder heating. test tube Used to hold test tubes while rack reactions happen in them or while they are not needed. thermometer Used to take temperature of solids, liquids, and gases. utility clamp Used to attach test tubes and other glassware to ring stand. 15  vacuum filter flask Used with vacuum line and Buchner funnel for vacuum filtration. volumetric Used to measure one specific flask volume in mixing accurate solutions. wash bottle Used to wash or rinse other containers watch glass Used to hold solids when being weighed or transported. They should never be heated. Can also be used to cover beakers or other containers. 16 weigh boat Used for weighing solids on a balance. wire gauze Used with a ring clamp to support glassware over a Bunsen burner. Spreads flame out for more even heating. 17  Dry Lab: Report Sheet The Laboratory Safety Name: ………………………….. Lab Section: ………………. Date: ……………….. read the laboratory safety and answers the following as true or false: 1. ( ) Tennis shorts and canvas shoes are proper clothing for "safe" experiments. 2. ( ) Even if an experiment appears not to pose any hazards, eye protection must still be worn. 3. ( ) A safety shower is located in your laboratory. 4. ( ) only injuries requiring treatment should be reported to your laboratory instructor. 5. ( ) changing in laboratory procedure is encouraged without authorization to heighten student's interest. 6. ( ) Working alone in the laboratory is not permitted in any circumstances. 7. ( ) Always wash your face, arms, and hands before leaving the laboratory. 8. ( ) Smoking, drinking, eating, and chewing gum are permitted outside of the laboratory only. 9. ( ) An eye wash fountain is located in your laboratory. 10. ( ) A first aid kit is located in the stockroom. 11. ( ) Never taste or smell a chemical or solution unless your laboratory instructor specifically directs you to do so. 12. ( ) If your data do not look right, change them; no one will know. 13. ( ) If a chemical spill occurs (even if it is small one), alert your laboratory instructor. 14. ( ) If a chemical spill requires you to use the safety shower, you should flood the affected area for 5 minutes. 15. ( ) Pouring acids over your hand is the accepted method for testing its strength. 16. ( ) If your skin is burned by a flame, treat it by covering it with salve. 17. ( ) Do not place book bags or athletic equipment on the floor near the laboratory bench. 18