CHEMISTRY 114

Laboratory Experiments

Summer 2012

Department of Chemistry Wilkes University

Wilkes-Barre PA 18766

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A MESSAGE FOR THE STUDENT The science of chemistry rests solidly on observations and quantitative data obtained from careful and critical experimentation by people who are curious to know how matter behaves. Some first-hand experience with apparatus and experimental methods is essential for a real understanding of the factual knowledge and basic principles of chemistry. You gain this experience by performing the experiments in this book. These experiments expose you to new concepts and ideas, sometimes even before they are discussed in lecture. This is appropriate because chemistry frequently advances from experimental results and interpretations to concepts and ideas, not the other way around. Other experiments give you experience in scientific inquiry and decision making. You will often be forced to make decisions on what seems like insufficient evidence, just as you frequently have to do everyday in nonscientific decisions. All experiments are written in such a way that you can begin with no prior knowledge providing one or more of the references are studied, but are also designed to build on any sound previous experience you may have had in chemistry. Those students who go on to more advanced courses in chemistry will acquire additional skills in synthetic methods and quantitative experimental techniques. Laboratory experiments are both fun and frustrating, and you should be prepared to experience both of these emotions. If you examine the list of exercises on this manual and read the exercises themselves you will find that the substance of the course and of the training we are trying to provide you comes down to a few basic operations: weighing, titration, and qualitative and quantitative analysis of various kinds. In the latter, which directly involve the first two, manipulation and handling of chemicals and samples whose amount or concentration must be preserved are the essential elements. Since these things are themselves such simple operations, surely there must be more to it than that! As already noted above, the something more is to get you to think about what you are doing, to understand it, and to learn to do it with ease and confidence. These things are what the course is really about. The lab has a rather different mission from the lecture course: to teach you to reason accurately from chemical observation and to teach you to make good measurements. We want you to do chemistry, to be a chemist doing the kinds of things chemists do, and, by extension to learn how to do science in general. The emphasis upon care and precision is at the heart of basic research. Many important discoveries have only come to light when precise data became available.

Course web site (www.chem.wilkes.edu/~mencer/chm114)

Plan to consult this web site early and often.

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CHEMISTRY DEPARTMENT POLICIES

• If you are absent see or call the instructor as soon as possible to arrange a time for a make-up lab.

• ATHLETES!! You already know your travel schedule (post-season tournaments excepted), so discuss any labs you may miss with your instructor NOW!! You can make definitive arrangements later (week of the lab) but let them know now.

• You are expected to complete all missed lab work either on another day during the week an experiment is given or during that week immediately following.

• If you will be gone on a family emergency, or are hospitalized please have someone notify us so we can set aside or remake what you will need. Otherwise, since we do not – and in some cases cannot store reagents indefinitely, you will have to make your own solutions as well as perform the experiment.

• Note that an excusal form allows you to make up the lab; it does not change the original due date of the laboratory report.

• If you do comply with the rule about excusal forms or abuse the use of them we may not be able to give credit for your work. These forms are necessary to preserve equity for everyone.

• There will be a charge assessed on any damaged instrument, and on certain community items that are particularly expensive and hard to replace.

• If you drop the course you must check out of your lab drawer or be assessed a $25 fine. • All appeals on grading problems will be considered by the instructor in charge only if

they are in writing. We reserve the right to regrade the entire test or report if any part of it is appealed.

• For scientific questions, start by seeing your instructor. If your instructor is not available consult another lab instructor. Office hours for lab instructors will be posted in the department’s board in the hall. If you have exhausted these reasonable resources, consult the professor in charge of coordinating the labs. Since this course is so large, he will see students in order as they request to consult him.

• Your reports must be in by the beginning of your regularly scheduled period of the week following completion of the experiment. You will be penalized 5% of the total possible points for each additional day that a report is handed in late. Extensions will be granted only by instructor.

WHY GREEN CHEMISTRY?

The focus of Green Chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. It is pollution prevention at the most fundamental level of atoms and molecules.1 The advances in Green Chemistry thus far address BOTH of those obvious hazards in addition to more global issues such as climate change, energy production, food production and safe drinking water supplies. In just over a decade of existence, Green Chemistry projects (at both the academic and industrial levels) have resulted in 57 groundbreaking technologies with the following STAGGARING accomplishments (Data taken from Chem. & Eng. News, 9 July 2007, p 35): 1 Kirchhoff, M. K.; J. Chem. Ed. 2001, 78, 1577

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1. 145 million pounds of hazardous chemicals and solvents eliminated PER YEAR!

This is equivalent to 700 tanker cars full of hazardous materials (a NINE MILE train).

2. 55 million gallons of water saved each year—the amount of water used by 2100 people.

3. 57 million pounds of CO2 no longer released into the atmosphere—equivalent to taking 6000 cars off the road.

The 12 Principles of Green Chemistry. 1. It is better to prevent waste than to treat or clean up waste after it is formed. 2. Synthetic methods should be designed to maximize the incorporation of all materials used

in the process into the final product 3. Wherever possible, synthetic methodologies should be designed to use and generate

substances that possess little or no toxicity to human health and the environment. 4. Chemical products should be designed to preserve efficacy of function while reducing

toxicity. 5. The use of auxiliary substances (solvents, separation agents) should be made unnecessary

wherever possible and innocuous when used. 6. Energy requirements should be recognized for their environmental and economic impacts

and should be minimized. Synthetic methods should be conducted at ambient temperature and pressure.

7. A raw material of feedstock should be renewable rather than depleting wherever technically and economically practicable.

8. Unnecessary derivitization (blocking group, protecting group) should be avoided wherever possible.

9. Catalytic reagents (as selective as possible) are superior to stoichiometric reagents. 10. Chemical products should be designed so that at the end of their function they do not

persist in the environment and break down into innocuous degradation products. 11. Analytical methodologies need to be further developed to allow for real-time, in-process

monitoring and control prior to the formation of hazardous substances. 12. Substances and the form of a substance used in a chemical process should be chosen so as

to minimize the potential for chemical accidents, including releases, explosions and fires.

Wilkes University and Responsible Environmental Stewardship

Currently, Wilkes University is in the planning stages to construct a new Science and Engineering Building—this plan further outlines the dedication of our University to the environment by calling for the design of a ‘Green Building’. The construction, maintenance, and operation of any building represents an enormous undertaking—Wilkes has chosen to go the extra mile and incorporate green building practices into the construction of the new Science/Engineering Building.

CHM 113 and 114 takes its first steps into the future of chemical laboratory experiences by adopting a ‘Green Chemistry’ approach to all of the labs. This change fits into the Wilkes University mission of educating our students in a constantly evolving world. This change is also

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in accord with our vision of cultivating civic responsibility and our ‘chemical ethics’ by incorporating responsible environmental stewardship into our laboratory processes.

In other words—the conscious effort for the impact of your actions does not begin when you enter the door of CHM113, nor does it end when you complete that week’s lab. “Green” is a conscious thought process; Green Chemistry represents a new way to THINK about chemistry. The labs contained within still teach you the same scientific principles that have been taught to generations of students before you. These labs will also have you thinking about how the procedures affect the larger world around you. Many of the labs will ask you to think about the procedure and your results in terms of those 12 principles—how the labs adhered to these principles, how they didn’t, and (most importantly) how these labs could be improved to better follow these guidelines without compromising the learning objective. Your first step into the world of Green Chemistry and improving the world around you starts with this lab! Good Luck and have an exciting semester.

LABORATORY TIPS Don’t forget your calculator! Your calculator is necessary for experimental calculations during the lab—while you have the materials and equipment at hand and can still remember what you have done. Do any weighing computations as soon as you have done the weighing and before you pour out a sample. Before you leave the balance, be sure you have written down the mass correctly. Do all calculations of titrations, etc., as soon as you complete them. In this way, errors such as failing to write down the initial buret reading become immediately obvious (and correcting said error is simple). Before you leave the lab, do the relative error calculations on a set of measurements so you can be sure they are close enough together to be acceptable. Laboratory Notebook Guidelines The notebooks will follow guidelines which would be required if you were working in an industrial laboratory. The notebook must be bound. For our purposes a scientific notebook is not required, any bound copybook will suffice but the pages must be numbered. It is your notebook, not ours. Use it to take notes of the pre-lab lectures. Leave room to edit or correct what you thought you saw or heard. This information will help you with the labs and lab reports. PUT YOU NAME ON IT. Many students forget this. Allow a page or two at the beginning for a “Table of Contents” Section. Notebooks will be periodically handed in for grading. Title, purpose, materials and procedure should be written prior to entering the lab. Results and calculations should be written during lab and conclusions can be written after lab. Formal reports must be written from your notebook and will be compared with the notebook to ensure authenticity.

You are expected to keep a current laboratory notebook. You are expected to record several classes of information in it:

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• All of the numbers and units pertaining to the experiment. This information must be recorded directly in your notebook, not on scraps of paper, since even if it is transferred once, there is danger of digits being interchanged, etc.

• All the observations you have made. This includes smells, colors and color changes. It includes the size and shape of solid crystals, abrupt changes in temperature, or any other phenomena. When in doubt, record it.

• Any changes in procedure. If you diluted a reagent down from a concentrated stock solution, record it. If there was a dead cockroach in your flask, when you did a titration, record it. When in doubt, record it.

• The notebook must be current and consecutive. All your semester’s work must be available to you at any time. The completeness will be checked on a periodic basis by the instructor.

• All data are entered directly into the notebook in permanent ink, NOT PENCIL! • All errors are crossed out by a single thin line only. The error must be legible. • Entries into the laboratory notebook must be neat and legible.

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Formal Report Guidelines

The following guidelines are similar to those used by journals affiliated with the American Chemical Society. In this case the guidelines are closely related to those used by the journal "Analytical Chemistry" and you should feel free to use articles published in this journal (available in the library) as examples for the preparation of your reports. The reports should be brief and not exceed 2000 words, with each figure or table representing 100 words. Manuscripts exceeding this word limit will be returned for editing.

The authors should use the past tense with the third person voice. For group experiments and reports with multiple authors, each author shall submit an individually composed report unless instructed to do otherwise. The paper should be typed using a word processor, double-spaced with a 12 point font. Pages should be numbered and the manuscript should be spell checked. Hand written papers will be returned without comment.

THE TEXT

Consult your instructor when necessary for details of the presentation. Do not include trivial details such as initial and final volumes of a titration or techniques that should be common knowledge to a student in an introductory chemistry course, e.g. pipeting techniques. Keep all information pertinent to a particular section within that section, i.e. do not discuss results in the experimental section. Avoid repetition. Do not include explanatory information in the references. General Organization The general sections of your formal report shall be the following:

• Title • Auhorship • Abstract • Introduction • Experimental • Results and Discussion • Conclusions • Acknowledgements • References

You will also add one additional section entitled "Accountability Statement" immediately following the references. A description of each section appears below followed by some tips on handling equations, calculations, figures, graphs, and tables.

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Title Use specific and informative titles with a high key word content. Indicate where

applicable, compound or element determined, method and special reagents (e.g. "Spectrophotometric Determination of Thallium in Biological Samples"). Do not use symbols, abbreviations or series designations. Use one complete title rather than a title and subtitle. Careful attention should be paid to choice of words (e.g. determination or analysis) to reflect correct usage. Authorship

Give authors names in as complete a form as possible. First names, initials and surnames should be included. Omit titles such as Dr., Ms., Mr., Ph.D., etc. Give the complete mailing address of the place of work for the authors. In this case, the department affiliation of your major will suffice. The corresponding author is indicated by an asterisk. For example:

Jane M. Doe* and John R. Doe

Department of Chemistry Wilkes University

Wilkes-Barre PA 18766 Abstract

The abstract (80-150 words) should describe briefly and clearly the purpose of the experiment, the principle results, and the major conclusions. State the objectives of the study, the limits of detection (when appropriate), the degree of accuracy and precision, and the major unique reagents, times, and temperatures. However, avoid abstracts that are merely a lengthy step by step recipe. The abstract should be essentially independent of the main text. Remember that the abstract will be the most widely read portion of the report/paper and will be used by the reader as an initial impression of the quality of the work. Introduction

The introduction should state the purpose of the investigation and its relationship to other work and areas of scientific investigation, but does not need to be an extensive review of the literature.

Experimental

Use complete sentences. Include all the information described below but do not use outline form. Instead, write the information as a narrative describing in a logical manner how the experiment was performed. Equipment: indicate the equipment and materials used for your study. Reagents: describe the source of all chemicals and the concentrations of solutions that were supplied for use in your study. Procedure: since all procedures are intended as instructions for other workers, give adequate details of critical steps to permit the work to be repeated by one of your peers. Note any special safety precautions that were required to perform the experiment.

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Results and Discussion

The results may be presented in tables or figures (see below); however, many simple findings can be presented directly in the text with no need for tables or figures. The laboratory instructions and data sheets should provide you with guidelines as to the nature of the primary data and the calculated results that should be included in this section. The laboratory manual may also ask questions or suggest material that should be discussed in this section. The discussion should be concise and deal with the interpretation of the results. In most cases combining results and discussion in a single section will give a clearer, more compact presentation, rather than using separate sections. Conclusions

Use conclusions for interpretation and not to summarize information already given in the text or abstract. This means that you should think about the broader implications of your reported work. What might an astute reader conclude from your work . . . say something worthwhile. Acknowledgements

You are encouraged to consult with others in the lab work and the development of your report, however, you should also acknowledge their efforts and thank them for their help. The following statement must always be included and signed by your group (when appropriate). References

References that are considered part of the permanent literature should be numbered in consecutive series by order of mention in the text. However the complete list of literature citations should appear in a single section titled "References". Reference numbers in the appropriate portion of the text should be placed in parentheses and on line. Please use the ACS format for references, e.g.

(1) Koile, Ross C.; Johnson, Dennis G. Anal. Chem. 1979, 51, 741. (2) Willard, Hobart H. Instrumental Analysis, 6th ed.; Van Nostrand: New York, 1981, Chapter 2. Scientific accountability and responsibility are very important. If the report is a group effort, the signatures of all group members must be included on a section that has the wording shown below. Accountability Statement "In signing this report, I/we understand that laboratory work in Chemistry 113 is composed of both individual and group work. If I/we have consulted with others in this work, their names and contributions appear in the acknowledgments section. The lab work and this lab report are the unique intellectual property of the person(s) listed as the authors of this report."

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FIGURES, TABLES, AND OTHER TIPS You should place tables in logical positions within the appropriate section of your report. A table with results belongs in the "Results and Discussion" section. On the other hand, it is best to place all figures at the end of the report (in correct order). Tables

Prepare tables in a consistent format, furnish each with an appropriate title, and numbered consecutively with Roman numerals in the order of reference in the text. Figures

Each figure should be printed full size on a separate sheet of paper to increase readability. All figures and graphs should be prepared using an appropriate computer drawing program and should clearly convey the desired information. Include consecutively numbered (Arabic numerals) figure captions in order of reference in the text. Keep captions as brief as possible and include detailed information in the text. Numbers, Nomenclature, Abbreviations and Equations

Use the standard format for presenting numbers. For example, .100M is not acceptable. The number should be presented with a zero before the decimal, e.g. 0.100 or in scientific notation, e.g. 1.00 x 10-1. There should be a space between the number and the unit, e.g. 0.100 M.

Nomenclature should conform with current American usage. Insofar as possible, authors should use systematic names similar to those taught in CHM 115 and 116. Use SI units of measurements and give dimensions for all terms. When using a unit be sure to use the correct symbolism. For example the symbol for milliliters is mL not ml. Balanced chemical reactions and mathematical equations should appear in the text to help clarify the discussion. Type all chemical and algebraic equations clearly and number all equations in consecutive order. For example,

The reaction of hydrochloric acid with sodium hydroxide results in a neutralization reaction (Eq. 1). H+ (aq) + OH- (aq) --> H2O (l) (1)

Chemical formulas should use the appropriate subscripts and superscripts (learn to use the word processor). The ACS Style Guide General information concerning American Chemical Society publications can be found in The ACS Style Guide, available from the Distribution Office, American Chemical Society, 1155 16the St. NW, Washington, DC 20036.

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SAFETY MANUAL

Safety in the Laboratory

Please observe the following rules:

1. Report any emergency, injury, chemical spill, or breakage to your TA immediately. All injuries must be reported, however trivial. What seems minor can have major complications.

2. At no time is an undergraduate student allowed to work in the laboratory without the supervision of an instructor. Students should perform authorized experiments only. Know what you are doing in the laboratory. If you don’t know how to go about an operation, ask someone who does.

3. Eye protection, in the form of safety glasses or safety goggles, must be worn at all times. Contact lenses should not be worn in the laboratory. They offer little protection, and if a chemical should enter the eye, they would hinder proper first aid, and greatly increase the possibility of serious eye injury. If contact lenses are worn, safety goggles are mandatory. All eye protection must have shatter proof lenses and side shields. If you wear prescription glasses that do not fit this description, you must wear safety goggles over your glasses. The temporary discomfort of safety glasses is a small price to pay to ensure the safety of your eyes. If you refuse to wear eye protection, you cannot come to the lab.

4. Eating, drinking, and smoking in the laboratory are strictly forbidden. Smoking is not permitted in SLC except in designated smoking areas. If you need to eat or drink, do it in the hall. Wash your hands before leaving the lab.

5. Closed shoes must be worn in the lab. Sandals are not permitted. Long hair should be tied back during the lab period. Dangling jewelry, long °oppy sleeves, loose garments, short skirts, shorts of any length, scarves, and neckties should not be worn in the lab. Don’t wear your best clothes to the lab. Wear old clothing or protect yourself with an apron or lab coat.

6. Keep aisles and corridors clear. Back packs, coats, unused books, etc. must be stored on the coat rack in each lab. Access to emergency equipment (fire extinguishers, eye washes, etc.) must be unobstructed.

7. When working with chemicals, gloves and lab coats (preferably with snaps for easy removal) are recommended. Always use the fume hood for chemical operations too hazardous to perform on the bench.

8. Mouth pipetting is strictly forbidden; always us a pipet bulb. 9. Burns and fires are serious hazards. Some substances you will work with burn very

easily. Also note that hot glassware looks very much like cold glassware, but its effect on your skin is very different.

10. Follow prescribed procedures for disposal of chemical waste for storage of chemicals. Do what you can to reduce the chemical waste.

11. Know the location of emergency exits, emergency showers, fire blankets, eyewash fountains and fire extinguishers. Always know two different ways out of the labs. In a real emergency, follow the instructions of the instructor, and move, don’t argue.

12. Don’t clown around. The margin for error is smaller in the lab than in most other places. Visitors are not permitted in the lab. If the visit is essential, see them in the hall!

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GENERAL HOUSEKEEPING

Proper maintenance of laboratory chemicals, apparatus, and equipment is essential for safe and efficient lab work. Keep lab benches, fume hoods, and shelves neat and orderly. Return all chemicals, apparatus, and equipment to their proper locations. Any chemicals stored under a fume hood for dispensation must be measured in that hood. Never take the bottle to your work area, or set up your work area in this hood. Be sure all chemicals are properly labeled. All unlabeled chemicals should be given to your TA or instructor for proper disposal. Promptly dispose of broken glass in the appropriate waste container. A dustpan and broom are located under the deionized water tap. Use them to pick up pieces of broken glass rather than your fingers. If you have a broken thermometer do not put the broken glass in glass waste: there may be mercury still inside. Call your TA to help you clean the mercury spill and put the broken glass in the thermometer case. Under no circumstances should a broken thermometer be placed in a wastebasket. Means of egress should be maintained free and clear.

DISPOSAL OF WASTE

Chemicals must not be thrown into wastebaskets. Always dispose of chemicals properly. Unused sample in vials, should be returned at the end of the lab period as is. Most solid waste may be dissolved in tap water and rinsed down the drain. Flush the drain area with plenty of water to be sure the chemical has been completely washed away. In general, rinse chemicals down the drain that are miscible with or soluble in water unless specifically instructed to use other means of disposal. Rinse drain well with water to be sure chemical has been completely flushed from the area. Organic solvents, radioactive chemicals, halogen waste, heavy metal waste, and precipitates insoluble in water will be collected in specially provided waste containers clearly marked as to content and located in each lab under a fume hood. Concentrated acids need to be neutralized with base before pouring down the drain. If there is no container for acid waste in the hood, ask your TA or instructor before spilling waste acid into the sink. Under no circumstances should chemicals be spilled into the deionized water drain or into the sink containing the eye wash!

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SPILL CLEAN-UP

Immediately call your TA for spills of any size. Do not attempt to clean it yourself. Spill kits and adsorbents are available in the preparation area.

• Solid spills: Spills of chemical solids are generally not difficult to clean up. Dry solid material (unless posing a specific hazard) can be swept together and brushed into a dustpan or onto a piece of heavy cardboard. Solids soluble in water or acetone can be dissolved in a beaker and flushed down the drain. Solids insoluble in common solvents or which should not be introduced into the drainage system (mercury compounds, explosive solids) can be transferred to glass waste bottles provided for such purposes in each lab.

• Inorganic acids: Spills of commonly used inorganic acids should be neutralized with sodium bicarbonate which is available in each laboratory. The wet sodium bicarbonate should then be swept into a dustpan, transferred to a pail containing cold water and carefully dissolved in the cold water. The resulting solution can then be flushed down the drain with excess water.

• Inorganic bases: The most common caustic alkalies are sodium hydroxide, potassium hydroxide, concentrated ammonium hydroxide and calcium oxide. Concentrated alkali solutions spilled on the floor may be flushed with water to a floor drain. If the spill is large and the base concentrated, seek assistance from your TA; it may be necessary to neutralize the spill with quantities of dilute acid but only after initially flushing the spill with water. Care should be taken during clean up as alkali solutions tend to make the floor slippery. Clean sand is useful for absorbing dampness that remains on the floor.

• Mercury: Metallic mercury spills are common laboratory occurrences resulting particularly from the breakage of thermometers. Mercury is corrosive to and readily absorbed through the skin: its vapors are poisonous and it volatilizes at room temperature. Hence considerable care should be taken when cleaning up mercury spills. After a spill, pools and droplets of mercury should be pushed together into a small area and collected by suction. An efficient vacuum device made from a filter flask, a long piece of suction tubing, one hole rubber stopper with glass insert and a piece of flexible rubber tubing attached to a Pasteur pipet is stored for common use. Complete recovery of all the mercury is virtually impossible, so steps must be taken to decrease the volatility of the remaining mercury. Sulfur dust, or a water slurry of sulfur and calcium oxide, should be spread over the entire area of the spill: residual mercury droplets will thus be coated with an effective barrier against vaporization.

• Bromine is a highly corrosive liquid with denser than air vapors. Bromine should only be handled in a hood with gloves and protective clothing. Never pipet bromine by mouth! A solution of sodium thiosulfate may be used to neutralize bromine spills.

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EMERGENCY PROCEDURES

Emergency Telephone Numbers For all emergencies, including fires, call x4999 Emergency Evacuation Procedure and Exit Routes SLC is protected by an early-warning fire detection system. Should a fire occur, a loud intermittent alarm will sound throughout the building. Evacuate the building immediately. Do not stop on the steps of the building. Emergency Evacuation Procedure

• Turn off all Bunsen burners, hot plates, etc. Make certain that stoppage of heating will not lead to any suck-back of water or other problems. Disconnect or shut off apparatus which might lead to further hazards.

• If possible, turn off the fume hoods and roof fans, or at least close the hood. • Vacate the lab, via emergency exit routes. Move as a group to the designated assembly

area outside, away from firemen and fire trucks. • Be prepared to describe to fire personnel the cause of the fire, the type of fire, what

chemicals and equipment are in the area, and any other relevant information that might aid them.

Emergency Exit Routes Primary emergency exit routes are posted by the exit door in each laboratory. Know the primary emergency exit route and familiarize yourself with one secondary route and all available exits in case the primary emergency exit route cannot be followed. When evacuating an area, always walk to the exit. If possible, close the door behind you as you leave to keep the fire contained in one area for as long a period as possible enabling evacuation to proceed. Stay with your group until roll is called. You may panic personnel needlessly by allowing them to believe you are still inside. Location and Use of Emergency Equipment Eye-Wash Fountains An eye-wash fountain is located in each of the undergraduate laboratories, at the front of the room. An eye-wash fountain must be employed as quickly as possible after eye contact with a chemical or corrosive vapors. Hence, be able to locate and operate a fountain rapidly. In most cases, eye-wash fountains are identified by a yellow color code (in general chemistry labs as a yellow stripe around the caps and a yellow sign on the lever) and can be operated by depressing the lever on the right side. The TA (or instructor) should ensure that the eye is flushed with a copious amount of water. Eyelids should be forcibly held apart so that the entire surface of the eye may be washed. Flushing should continue for at least 15 minutes. NEVER apply a neutralizing solution as first aid! See an ophthalmologist at once.

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Fire Fighting Equipment The types of fire-fighting equipment provided for use in the undergraduate laboratories: fire blankets, showers, portable fire extinguishers. Fire blankets are located in the lab corridors. They are stored in red, rectangular containers mounted on the walls and provide a handle or cord with which the blanket can be rapidly extracted. A fire blanket may be used to smother a flammable liquid fire in a small open container but its major purpose is to extinguish burning clothing. If a safety shower is nearby, the blanket should be used only to transfer the victim to and from the shower; a shower is a preferable mode of smothering the fire because clothes will continue to smolder under a blanket. Safety showers are located in the lab’s corridor. Safety showers should always be used to drench burning clothing and to flush chemical spills from body and clothing. They can be operated by pulling the chain. Portable fire extinguishers of two types (carbon dioxide, dry chemical) are available in the undergraduate laboratories. Each general chemistry lab contains at least two carbon dioxide extinguishers for use in extinguishing flammable liquid, flammable gas, and electrical fires. In addition, there is a multi-purpose dry chemical extinguisher in the preparation area for use on all fires. First Aid Kits: A limited first aid kit consisting of band-aids, gauze and ointments, Tylenol and smelling salts is available in the lab preparation area for minor cuts and burns. These supplies are intentionally limited to prevent treatment of serious injuries by non-medical personnel. For all injuries, the instructor or TA should be contacted. Charts of Dangerous Materials: A Dangerous Materials chart has been placed in room 261. For commonly-used chemicals, these charts identify any health hazards involved, safety precautions necessary, fire-fighting equipment that may be used, and certain first aid instructions. Moreover, emergency telephone numbers are listed at the bottom of each chart. Fires Most fires can be avoided if safe laboratory procedures are conscientiously followed.

• Be aware of the chemical reagents being used in the lab. Keep flammable chemicals and their fumes away from heat sources. Any chemicals stored under a fume hood for dispensation must be measured in that hood. Never take the bottle to your work area, or set up your work area in this hood. Such reagents are flammable, toxic, or both and are stored in such a manner as to ensure your safety.

• Be sure all burners, hot plates, heating mantles, steam baths, etc. have been turned off before you leave the laboratory.

• Never walk away from a reaction. Watch it carefully at all times no matter how slowly it seems to be proceeding.

• Smoking is strictly prohibited in the laboratory and is not permitted inside the building except in designated smoking areas.

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Should a fire occur a. Minor fire: one that can be easily and immediately extinguished.

1. Call your TA. 2. Remove the heat source (turn off burners, hot pates, etc.). 3. If the fire is contained within a vessel or confined to a small area, attempt to suffocate it

by placing a large beaker over the area. b. Major fire: any fire that cannot be contained and extinguished immediately.

1. Promptly evacuate the lab. 2. Sound the general alarm to evacuate the building. Know where the pull alarms are and

how to use them in the event you are called upon to do so. 3. If fumes are hazardous or the fire is smoky, stay low to the ground and take short breaths;

cover your face with a cloth if possible to help filter out the smoke and protect the skin from heat.

4. Should you need to call the emergency number to summon assistance, be sure to speak slowly and distinctly. Give the fire location and specific information about its nature. Don’t hang up until you have answered all pertinent questions and you are sure you have been understood.

5. Should you find access from the building blocked, seek out a temporary place of shelter until help arrives. Stairwells marked EXIT are suitable areas usually enclosed by solid walls. Offices or classrooms with windows may be temporarily suitable If all doors are closed and windows opened and you sit straddling the window sill until rescued.

First Aid Procedures Should a laboratory accident occur, it is the responsibility of the TA and instructor to initiate first aid treatment and contact the necessary personnel. Do not attempt to aid another student who is involved in an accident. Remain calm, and immediately notify the nearest available person authorized to administer first aid: your own TA, the TA in an adjoining laboratory, the instructor or the lab preparer. Be aware of the consequences of a laboratory accident, and be prepared to act, if need arises, calmly and logically in the interest of your own safety. Toxic Fumes If poisonous vapors from a spilled chemical or chemical fire begin to saturate the lab, move to a safe area as son as possible: the corridor, closing the door behind you, or out the nearest exit door to exit the building. Live electrical connections If you suspect a student is in contact with a live electrical circuit do not touch him! Call for assistance at once. Cuts and bleeding If a student nearby has suffered a nasty wound and begins bleeding profusely, call for assistance and stay with the insured student until the assistance arrives. Once the student has been attended, you may call attention to burners or hot plates which should be turned off, or reactions which

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should not be left unattended. If the wound is minor, rinse the area well (10-15 minutes) under running tap water to prevent any chemicals on the surface from entering the wound. Show it to your TA and cover it with a band-aid or gauze available in the prep room. Fires Never go to the area of a laboratory fire. If needed, call for assistance where you are. If the fire has been quickly contained, go on with your experiment. If is should not be contained in the first few seconds following onset, be prepared to evacuate the lab. Fainting Should you feel faint, lie down on the °oor, or if time, try to reach a chair away from lab benches and sit quietly with head lowered below the knees, until the feeling has passed. Should someone nearby fall in a faint, call for help at once. If you notice he has fallen on a chemical sample or reaction vessel, be sure to inform the attending personnel. Bathe the victim’s face and forehead with a clean towel soaked with cool water until consciousness returns. Inhalation of Chemicals or Chemical Vapors Remove victim from contaminated area to fresh air as quickly as possible. If possible inform TA or instructor of the substance to which the victim was exposed. Burns Burns from hot glassware or the base of the Bunsen burner should be treated at once with a ice/water mixture, either by directly putting the burned area into a large beaker (or other clean container) containing the mixture, or by wrapping ice in a clean towel and applying it to the burned area, changing the ice every 5-10 minutes. Chemical burns from acids, alkali, oxidizing or reducing agents corrosive to skin should be washed with cold water immediately. Continue flushing the area until the burn stops hurting or until medical assistance has arrived. In the event of a major chemical spill covering a large portion of clothes and body, you must use the safety shower. In all cases, even the most minor, ALWAYS inform your instructor. Special Precautions for Bromine Contact with bromine will lead to excruciatingly painful burns. Gloves and safety goggles should always be worn and procedures should be carried out in the hood. In the case of bromine burns, immediately flush the area with cold water, contact Health Services, and transfer the victim. Do not use any other chemicals to neutralize bromine burns on the skin. If clothing is contaminated, it must be removed.

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GENERAL LABORATORY INSTRUCTIONS

The laboratory is equipped with work benches that provide space on which to work and contain individual equipment drawers or lockers. You will be assigned a drawer containing glassware and equipment for your use during the term. You will be asked to check the contents of your drawer and compare them to a list provided during check-in at the beginning of the first laboratory period to familiarize yourself with everything you will commonly use. You will be responsible for all items in your locker, and required to keep your own glassware clean. These items dent Christmas budgets if you break them (e.g. burets >$80). BE CAREFUL!!

Cleaning Glassware When you begin an experiment, all your glassware should be clean. You will be responsible for the initial cleaning of your glassware and for and keeping it clean for the rest of the year. Usually rinsing with copious amounts of tap water followed by a distilled water rinse after use should be adequate for dilute solutions. The standard test for cleanliness is to watch a film of distilled water run down the inside of the vessel. The water should flow down the inside surface in sheets and should not bead up. If water beads up anywhere on the interior of the vessel, wash it in hot water with a diluted solution of the detergent (kept by the deionized water tap) and scrub the inside with the brush from your drawer. Rinse thoroughly with tap water to remove all the detergent. If this is not done, the film left by the soap, which is strongly basic, may affect future experiments. Usually laboratory glassware is given a final rinse with deionized water to remove any contaminants that may be present in tap water. Deionized water is very expensive to produce and is shared by all labs and research groups in SLC. It cannot and must not be used for rinsing in great quantities; never use it to wash glassware. Fill the wash bottle from your locker with deionized water, and rinse your cleaned and rinsed glassware with 2-3 separate 10-ml portions of deionized water from the wash bottle. You may dry the outside of the vessel with your towel or paper towels, but never dry the inside, lest you leave lint or other contaminants. Let the glassware dry in your desk until the next lab period. If you need to use dry glassware immediately, and the vessel is not finely calibrated or volumetric, you may either dry it in the drying oven, or use a small amount of acetone to rinse the inside of the vessel, which will dry in a few minutes. Burets must never be washed with detergent under any circumstances. Please see the special section on the care and use of burets for specific instructions.

Reagents There are a couple of basic rules associated with reagents. The reagents for all experiments will be prepared to the proper concentration you will need. They will be labeled with a chemical name and the molar concentration, and will be found in the first two hoods in each lab.

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Read the labels carefully: quite often different molar concentrations of the same reagent are used during the same lab; confusing them will greatly affect your results. Never take reagent bottles away from the hoods. Take a beaker, flask or graduated cylinder with you to obtain what you need. Take only what you need! Taking more than you need “just to make sure I have enough” produces needless waste and shows you have no idea what you’re doing in the lab. Take only the quantity of reagent specified in the experiment. If you do have an excess, ask if someone else in the lab can use it before you dispose of it. Always put the cap back—NEVER leave a reagent bottle open!! Replacing the cap on reagent bottles immediately avoids the potential problem of cross contaminating reagents. Liquids are usually stored in narrow-neck bottles with screw caps. To dispense remove the screw cap and hold it in your hand while pouring the liquid into a graduate cylinder, beaker or flask. Never place caps down on the reagent bench! Solid reagents are normally dispensed in pre-weighed sample vials. You will weigh them by difference and return the unused solid as is in the vial to the hood when through. If a solid is to be weighed from a reagent bottle, there will be a spatula in a test tube holder attached to the bottle. Use only that spatula, and weigh into a small beaker or onto weighing paper (in manila envelope near each balance). Never store reagents in your desk unless specifically instructed to do so. Dispose of all used reagents properly. If a solution cannot be flushed down sink drains, or if a solid (eg. a precipitate) cannot be dissolved in water and flushed down the sink drain, a specifically labeled waste container for it will be in the hood. Always check with your TA before disposing of any reagents and products. (see also section on waste disposal in the chapter on safety.)

Using Volumetric Glassware Volumetric glassware is used when precise volumes are needed. Types of volumetric glassware you will use are vol. flasks, vol. pipettes, graduated cylinders, and burets. How to measure volumes with your buret. Reading your buret properly significantly affects the quality of your results. The figure on the right shows the proper technique (making sure your eye aligns with the bottom of the meniscus). Care of your buret. Since burets are expensive and will be shared, you must use great care in their use and cleaning. You will find burets attached by a buret clamp to the ring stand at your work station.

1. They will be upside-down with the stopcock open. 2. Rinse the buret with two portions of deionized water.

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3. Check the flow of water from the stopcock (obtain new stopcock from your TA if yours doesn’t perform properly.

4. Now rinse the buret with two portions of your solution (the first portion removes the excess water and avoids diluting your solution).

5. Fill the buret NEAR the 0.0 mark. Since the volume measured by a buret is determined by the difference between the initial volume and the final volume it is not necessary to waste time adjusting the initial level to the zero mark.

6. Remove any air bubbles in the stopcock tip (have your TA demonstrate this). 7. When you have finished titrating, empty the burets into the sink and rinse well with tap

water as before. Never use soap or place the buret in the sink! 8. Clamp the buret upside down with the stopcock open for the next lab.

Pipets are used as follows if using a rubber bulb or pipet pump.

1. Squeeze the air out of the bulb before filling pipet with liquid. Insert the glass carefully into the bulb, just until it remains inside. Fill above the mark, but do not allow liquid to enter the bulb.

2. Remove the bulb while covering the top of the pipet with your index finger. 3. Release the pressure from your finger slightly to drain the pipet until the meniscus

drops slowly to the mark. 4. Release the liquid into the final container, touching the pipet to the side of the container

to drain all of the calibrated volume. For specific experiments we will provide plastic pipet fillers which are designed to fill pipets and deliver liquids with speed and precision.

1. Hold the pipet close to its upper end and insert into the pump with slight pressure to assure a secure fit. 2. Submerge the end of the pipet into the solution and turn the wheel with your thumb. To expel fluid, turn the wheel in the opposite direction or, press down on the plunger top. 3. To remove the pipet, hold it near the chuck, twist slightly and pull down.

USING BALANCES

We will most often be using small mounts of solid whose weight must be accurately known. For this purpose the analytical balance, with an uncertainty of 0.0001 g. will be used. These balances are very sensitive: treat them with respect and care. The balances will always be turned on and calibrated for your use. These balances are designed to give an accurate weight measurement within seconds after placing the object on the pan. No adjustment should be necessary. To operate:

1. Display should read 0.0000 g. If it does not, press the or bar beneath the display once, and wait for zero to appear on the display. Do not be impatient: every touch represents a command which the balance will follow; pressed a number of times in succession, the balance will go into the mode until it has answered all commands.

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2. Open one door slowly and gently place the object to be weighed onto the pan. (Never weigh reagents directly onto the pan!) Close both doors slowly. 3. Record the first steady reading with a g on the right side. If an object is light, this reading may fluctuate; in this case, take the first reading that stays on the display for 3 seconds or longer. If an object is hot, fluctuation will be rapid and continuous; remove the object until it has cooled longer and try again. 4. Gently remove the object and let the display return to zero. If it does not, press once. If you have spilled solid inside the balance, clean it immediately using the brush stored on the balance floor. Close both doors.

A slight difference in the balance point of each balance is usual. Therefore, it is strongly recommended that you use the same balance for all measurements throughout an experiment. You may not use beakers or flasks greater than 125 mL. on the pan. The balance has a capacity of 100.0 g. If an “-----” or other “non-numerical result” appears on the display, it indicates that what you are weighing exceeds balance capacity.