1. Wear approved eye protection when you or others are working with chemicals or apparatus. 2. Wear chemically resistant laboratory gown or clothing that is suitable for laboratory work, to provide maximum protection. 3. Do not wear high heeled shoes, open toed shoes, sandals or shoes made of woven materials. 4. Confine long hair and loose clothing. 5. Place items such as purses, backpacks, extra books, and other things in designated area. 6. Never work alone in the laboratory. Never perform unauthorized experiment. 7. Never engage in any play, trouble, or other acts of mischief in the laboratory 8. Use good judgement and care when working in the laboratory. ACS – American Chemical Society PACT – Philippine Association of Chemistry Teachers EMB – DENR – Environmental Management Bureau – Department of Environment and Natural Resources Accident Prevention – is a collective responsibility that requires the full cooperation of everybody in the laboratory. 3 reasons: Indifferent attitude Failure to use common sense Failure to follow instructions, making a mistake Become involved; participate in the practice of preventing accident. Corrosive substances – are acidic and basic and are capable of corroding metals. Reactive substances – are unstable under normal conditions and readily undergo violent changes without detonating. (cause to explode) Water – most dangerous single chemical known. Toxic Chemicals – chemicals that could be of virgin materials that are poisonous Hazardous Chemicals – A chemical that presents a hazard either under normal use or in a foreseeable emergency. Toxic chemicals can enter the body by four routes: Activity #1 Chemicals Safety in the Laboratory Toxic substances – are poisonous and To understand the importance of knowing the chemical hazards and the necessity of taking appropriate precautions to reduce the probability of accident. have carcinogenic, tetratogenic, and mutagenic effect on human and other organisms Flammable Substances – can create fire under certain conditions Inhalation through respiratory tract by breathing. Ingestion through digestive tract. This can occur through eating, chewing gums, applying makeup or smoking in the laboratory. Absorption through body openings such as ears or eyeball socket, through cuts in the skin, or even through intact skin. Injection of a toxic substance though a cut made in the skin by a sharp contaminated object. Health Hazards Fire Safety Toxic skin 1. Go out to a place of safety 2. Help the handicapped Irritant/Sensitization Acute Toxicity / Aquatic Hazard Sources of Information Environmental Hazard Material Safety Data Sheets (MSDS) Environment and Corrosion 3. Don’t run or panic. Don’t use elevators 4. Go to ground level into the open air 5. Go to your assembly point. Labels Catalogue Fume Hood Posters - Laboratory chemical hood is a ventilated enclosure that protects you from being exposed to chemical fumes, gases, and aerosols that are generated within the enclosure. Safety data Safety labelling Mixed storage of chemicals Periodic table Emergency Exits 1. 2. 3. 4. 5. 6. The sign must be clear Show the way to the closest exit Equipped with emergency lighting Never locked Free from bags and other equipment Directly connected to emergency stairs Signage Internet Fire Theory Oxygen – energy – flammable material Globally Harmonized System (GHS) - Its goals are harmonized criteria for the classification for physical, health, and ecological hazards. Classes of Fire Class A – fires of solid materials Explosive Flammable Oxidizing Compress gas Corrosive to metals 1. 2. 3. 4. Physically dangerous Biologically dangerous Chemically dangerous Hazard people (wood,paper) Class B – fires of liquid materials Physical Hazards Sources of Danger (alcohol,oil) Class C – fires of gases (methane,hydrogen) Class D – fires of metal (aluminium,sodium) Danger – it signifies that the hazard can cause serious injury or death Warning – it signifies that the hazard can cause less that serious injuries Caution – warns users to be careful in using, handling, or storing chemicals. Flammable substances CREATES fire while oxidizers INCREASES fire. Procedure Test tube holder – used to hold test tubes 1. Measuring and Estimating Liquid Volumes Wire Gauze – helps in supporting the beakers, flasks or other glassware during heating. - Lower meniscus Beakers – used to store, mix, and heat liquids. Evaporating dish – used to evaporate excess solvents. Glass rod – allows the water to flow along it - Filled with water up to the 10ml mark - Estimation of 2ml, 5ml, and 10ml. 2. Transferring Liquids - Using a glass rod 3. Heating liquids in the test tubes 5. Filtration A process used to separate solids from liquids using a filter medium that allows the liquid to pass through but not the solid. The liquid that passes through the filter paper is called filtrate. 6. Decantation - A process to separate mixtures by removing a liquid layer that is free of a precipitate. - Half filled with water EXPERIMENT # 1 COMMON LABORATORY OPERATIONS To become acquainted with some common laboratory operations To demonstrate proper laboratory techniques and skills involved in some common laboratory operations - Held at an angle of 45 degrees to 7. Evaporation - move the test tube in and out in the flame to control the heating rate. Process by which molecules undergo the spontaneous transition from the liquid phase to the gas phase due to an increase of temperature. All the liquid has evaporated. - Do not point the opening end of the test tube to another person - Heat first the upper portion rather than the bottom 4. Precipitation It is the formation of an insoluble compound when mixing two different solutions. This solid is called the precipitate. The solid resulting from the said process is called the residue. Experiment #2 EXPERIMENT # 3 Coffee Cup Calorimetry HEAT OF COMBUSTION: CALORIC VALUE OF FOODS To determine the specific heat of a metal using a coffee cup calorimeter. To determine the energy released per gram of food burned; and To compare the caloric content of different food samples. What happens when a hot object is placed in a container with a cooler bath of water? - The hot object when placed in a container with a cooler bath of water releases heat thus the water absorbs heat released from the object. Where does heat go? - Heat released by the metal was being absorbed by the water. Possible errors: Insufficient seal of the cup that causes the heat to go to the surroundings. Inaccurate measurements Scientific calorie – amount of energy required to increase the temperature of 1 g of water by 1 degree Celsius. Almonds provide the highest energy per gram. Most nuts like almonds are known for their high calories. EXPERIMENT # 4 Procedure - 50 ml of water inside the soda can Weigh 2 grams of each food sample Put the sample in the paper clip and weigh it. Measure the initial temperature Ignite the food. Measure the final temperature and weigh the food sample. Calculate the energy released by the burning food sample. What is a calorie? - A calorie is a unit of energy that is used in nutrition. Food calorie – the amount of energy needed to raise the temperature of 1 kilogram of water by 1 degree Celsius REACTIVITY OF METALS AND SOME ASPECTS OF CORROSION To identify an unknown metal using their reactions with know metals Five metals - Mg Zn Al Fe Cu Solutions - HCL Al2(SO4)3 CuSO4 Ordinary iron nail corrodes and rusts easily. - Explain why galvanized sheets used as roofing materials are often painted red? What is the composition of red paint? - - The red paint or red lead is used in painting roofing materials to prevent it from rusting. Red lead is composed of mixed lead oxide containing Pb+2 and Pb+4 lead ions with an overall formula of Pb3O4. Discuss the significance of knowing reactivity of metals in solving rusting or corrosion. - - The reactivity series allows us to predict how metals will react. Whether it will easily rust or corrode. It is important that you learn the - PLASTICS AND POLYMERS reactivity series because it enables To determine some properties you to determine which cation will of different types of polymers replace the other from its aqueous thermoplastics. solution. Galvanized iron is iron which has been coated in a layer of zinc to help the metal resist corrosion. EXPERIMENT # 5 To identify the types of polymer on the basis of their properties. HDPE – high density polyethylene HDPE is used in the production of plastic bottles, corrosionresistant piping, geomembranes and plastic lumber. High density polyethylene is a hydrocarbon polymer that can be prepared from ethylene via a catalytic process. known for their excellent combination of properties such as mechanical, thermal, chemical resistance as well as dimensional stability. a clear, strong, and lightweight plastic that is widely used for packaging foods and beverages, especially conveniencesized soft drinks, juices and water. Polystyrene also is made into a foam material, is used for producing disposable plastic cutlery and dinnerware, CD "jewel" cases, smoke detector housings, license plate frames, plastic model assembly kits, and many other objects where a rigid, economical plastic is desired. PP – polypropylene LDPE – low density polyethylene LDPE is primarily used in film applications because it is tough, flexible and relatively transparent. LDPE is also used to produce some flexible lids and bottles as well as in wire and cable applications. Polypropylene (PP) is a rigid and crystalline thermoplastic used widely in everyday objects like packaging trays, household products, battery cases, medical devices PP is among the cheapest plastics available today. PET – polyethylene terephthalate is a general-purpose thermoplastic polymer which belongs to the polyester family of polymers. Polyester resins are PVC – polyvinyl chloride is an economical and versatile thermoplastic polymer widely used in building and construction industry to produce door and window profiles, pipes (drinking and wastewater), wire and cable insulation, medical devices etc. PS – polystyrene (in solid form)
