CHEMISTRY 0113

Your lab notebook is supposed to be a personal record of your experiments. However, it must be neat and organized. You will keep a laboratory notebook in which you make one original copy and a (carbonless) copy and turn in the copy as your lab report. You will keep the original to study for the quizzes and final exam. You should make all entries in ink as they occur. Leave the first two pages of the notebook blank to prepare a Table of Contents and update it as you complete each report. Start each new experiment on a new page. You will use the notebook to organize your plan for each experiment, collect data, make observations carry out calculations and draw conclusions. You may also want to make notes from the Pre-Lab discussion in your notebook.

Preparing for the Experiment:
• Pre-Lab assignment
• Preparing notebook: Purpose, Proceudre & Equipment List
• Setting up Data Tables
• Notes about calculations
• During the Lab Period
• Observations and/or modifications to the procedure
• Recording data
• Prepare Graphs, Carry out Calculations
• Analyze data -- especially error analysis
• Lab Report
• Pre-Lab material
• Record of data & calculations
• Answer questions
• Discuss Results
• Other Notes
• Cooperative Learning / Doing experiments as a Team
• Assessment: Participation & Process

Read the experiment through completely. Start on a fresh page in your notebook and prepare a worksheet using the example in figure 3-1 of How to Survive. While you may not use all five sections for every lab, the worksheet will help guide you in thinking about what is important.

1. Vocabulary - unfamiliar terms? new chemicals? These are fair game for a quiz. You may find definitions in your text book.
2. Equations - chemical and mathematical - Does the experiment involve a chemical reaction? How does it relate to lecture? What about mathematical calculations? You can probably find the relevant equation in your text book. These are also "fair game" for a quiz.
3. Summary -
4. Plan for action - What will you do first? Second? Etc. The Summary and Plan for Action will help you develop an excellent Procedure section in your notebook.
5. Special things to remember --Ask yourself these questions:
1. Calculations to be done before coming to the lab? Values to be looked up?
2. Anything that requires special attention?
3. Anything that I need to remember to bring to the lab?
• Pre-Lab assignment:-- Every experiment has a pre-lab reading assignment. Most of the experiments have Pre-Lab questions. You can find these on BlackBoard the syllabus has links for each experiment. Use a fresh page of your notebook -- after your "worksheet" -- for the pre-lab problems.  Sometimes these are collected --without advance warning!

Read the experiment again and use your worksheet from step 1 above to set up the first part of your lab report. Start this on a fresh page of your lab notebook.
• Purpose: You can write the purpose all the way across the page! It should be a clear, concise statement of the purpose of the experiment. Do not copy word for word from the manual. It should summarize what you expect to learn and be a complete sentence. "To determine the gas constant" is not a complete sentence; there is no subject. You really do have to read the whole lab before writing the purpose.

The purpose should answer these questions:
• Why am I doing this lab?
• In what way does it relate to what we are studying in class?
• What do I hope to learn?
• List of equipment needed: You will find some in your lab drawer; the rest will be provided. 

What will you need that you know is in your drawer or elsewhere in the lab/balance room?

What will you need that you will find on the cart or along the top of the bench?                                         Back

• Summary of the procedure: It is very helpful if you begin the procedure on a fresh page -- especially for labs with multiple parts (like "Density of Solids & Liquids", "Titration" and "Absorption Spectra"). Note that your lab notebook has a vertical line down each page. Use the left-hand side to write out the steps of the procedure based on what you have read in the lab manual. Do not copy the procedure verbatim from the lab manual. It will not be helpful. You want to understand the basics of the experimental procedure. Write down the steps (as you understand them) using your own words in the past tense and active voice. These will be the steps that you will follow during the laboratory session; you cannot refer to the laboratory manual. Remember that "Plan for Action"? It will help you devise your procedure!

A detailed step-by-step list of manipulations is not necessary. The procedure should have enough detail so you can do the experiment without using the lab manual. "Determine Density" is too Brief. "Get deionized water from the carboy" is probably too much detail!

Write in complete sentences in past tense and active voice. In other words, use phrases like "I placed the previously weighed insoluble solid in a graduated cylinder containing 10 to 15 mL of water." Note that you didn't say that you weighed the solid to the nearest 0.001 G or that you recorded the mass in your lab notebook! Statements like this are unnecessary redundancies! If the balance reads to three decimal places, obviously you will record the mass to three decimal places.

The words "calculate" and "record" do not go in the steps of the procedure. Obviously, if you measure something (mass, volume, temp, etc.) you will record it. That is why you create a data table!

Words like next and then are not necessary. If you write clearly, the order of steps will be obvious!

If you vary from the published procedure, either on your instructor's direction or on your own initiative, you should note these variations on the right-hand side (during the lab session). It is a good idea to leave a line or two following each step.

When the procedure in the lab manual says "Design an experiment", you must write the steps that you actually took in the right-hand column (next to where you wrote "Design an experiment".)

The procedures in the lab manual sometimes ask you to think about a question. This isn't really a part of the procedure. Perhaps the thing to do is to write the question in the RH column next to the spot in the procedure where you should examine this idea. You could jot down your initial reaction and then incorporate that into the results and/or the conclusion.

Including detailed instructions for using the computer to record data or generate a graph is not. Phrases like "save the experiment under your name" and "Click OK" are not necessary. I assume you have a certain minimal competency with computers. On the other hand, when you do save a file, be sure to list the filename as a part of your data/observations. After all, you will want to be able to find it later! Instructions to print data (or plot, etc.) are unnecessary. I world hope that you plan to include a printout with your lab report.

Test tubes & other glassware - No one likes to use dirty glassware; you will always use a clean piece. However, you don't need to tell me that you used a "clean, dry test tube". Similarly, if you use multiple beakers or test-tube (and don't want to be confused) you'll want to label them. However, the phrase "Label test tubes" is not a part of the procedure. It's an obvious part of good laboratory practice.

• Data Table for collecting experimental data. Come to the lab with data tables prepared for data collection. There may be a sample data table in some of the laboratory procedures. Often you will find a recommended outline for the data table. Follow these recommendations whenever you can! You are to record all data in your notebook. Be sure to leave lots of space for data. Some additional comments:

The data table can take up the entire width of the page! Make them clear and easy to read (without my needing a magnifying glass!).

Units and significant figs are essential. If you aren't sure how many significant figs (ie -decimal places) to write down for a specific piece of equipment (graduated cylinder vs. electronic balance) check the table on the handout!

It helps (me when I'm grading) if you put a descriptive title on your data tables.

The experiments frequently have instructions for creating data tables. Considering the kind of information you will be collecting is helpful. Also, think about the logical (chronological) progression of how you will collect the data (be it numerical data from instrumentation or qualitative observations). For example:

If you measure the volume of an object by displacement of water, the manual probably only says "record volume". Yet, you need to record both the initial volume and the final volume of the water because the volume of the object is the difference!

If you must make repeated trials of a particular kind of measurement, where would be the best place (columns of rows?) to put "trial 1", "trial 2", etc.

If you have individual data and collected data from the class, which table should come first? Don't you need to collect your own data and do the necessary calculations to generate class data?

Spend just a few minutes thinking about this part of the procedure while doing your pre-lab preparation and you can make some notes (RH column) about this in the procedure. You can also make entries for these measurements in your data table. It will make a huge difference in how smoothly your lab goes!

Remember, if you split chores among the different members of your team everyone has to have the same data when the experiment is over. During the first few pre-lab sessions we will discuss how to set up data tables. As the term progresses you will begin to develop a better idea of what should go into a data table.

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Record all variations from the original procedure on the right-hand side opposite the original steps.

Record observations and data.

You should record all experimental observations and data in ink directly into the notebook at the time of observation. Do not record figures on loose scraps of paper to be copied neatly into the notebook later. The data may be lost and copying destroys the value of the notebook as the original record of your laboratory work.

You should properly label all numerical data; use the correct number of significant figures and proper units!

Drawgraphs if necessary. Although you will generate most of your graphs using the Graphical Analysis software, the general rules of graphing apply. Again, you need numerical data to draw graphs so (logically) data will come before graphs. When the data is collected electronically, then you will generate your graphs on the computer. A few notes of how you generated the graph will be helpful; include the graph in your lab report.

Each axis should be properly labeled and contain the proper units. Each graph should have a title.

You don't have to start the scale of the axis at 0,0 unless otherwise stated. Chose a scale that is easily divisible and makes the graph cover as much of a full page as possible.

Use a + when plotting points on your graph.

Calculations: Show all calculations unless otherwise stated; be sure to label this section "Calculations".

• In two to four words describe each calculation ("volume of water from density", "density of solid using Archimedes Principle", etc.) You only need to show one calculation.
• Be sure to use units and show how they cancel!
• Sig figs are essential in all calculations; SF count 1 point for every calculation!
• For calculations that require several steps do not round the answer until after the last calculation -- this eliminates possible "rounding error".
• Remember: you have to have data to do calculations so (logically) data will come before calculations.
• If you use your calculator or the computer to record or manipulate data, be sure to list the steps you took to record/manipulate that data.

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Your lab report is the carbon copy. You will submit the completed Lab Report at the end of the lab period and include:

Your Pre-Lab preparation (Steps 1 through 5 under "Before coming to lab").

All of the data and observations you recorded during the lab; units and significant digits are very significant!

All of your calculations and any graphs that you prepared.

A record of your results and a summary of your observations as specified by the instructor. Include the ID numbers for any unknown sample when appropriate.

A few comments about results: You have to collect data, make observations and carry out calculations and/or draw graphs to have results. Therefore think carefully about what makes up the results for each experiment and where they belong in the progression of your laboratory report.
• The answers to assigned questions at the end of the experiment in the laboratory procedure.
• A brief discussion (one to three well-organized paragraphs). This is the part of the report where you look back over the experiment (data collected, observations made, calculations and analysis as graphs, etc.), discuss your results and say whether you could prove your hypothesis (ie -- the purpose) and how.
• The discussion goes at the end (including the questions that asked along the way). It makes it easier for me to read!
• Show that you have thought about what you did in the experiment. Also, comment on data analysis (significance of any graphs, etc.) and likely sources of error.
• The discussion mus include some mention of the results. For example, in the first lab you should at least report the densities obtained for the solid and unknown liquid and say something about the % error. Something similar to "We determined the density of lead pieces to be This is % off from the accepted value of 11.34 g cm^-3. Some possible reasons for this are "
• Error analysis -- "Human error" and "instrument error" are not acceptable! If it is human error (that you overshot the phenolphthalein endpoint in the titration), then how will this (large volume) affect your calculated value for the concentration of the standardized NaOH solution (higher than true or lower?).
• If you had trouble pipetting, then how does the "true" volume compare with the "recorded" volume? Will the value you calculate for the density be higher that it should really be or lower?
• When you say "Instrument error", do you mean that the balance was improperly calibrated? How would you know this? How would it affect the values that you calculate? What if there was a bubble in the mercury in the thermometer? How would this affect your reading of the temperature? Would this cause the calculated value of the volume of gas (using PV = nRT) be lower or higher than it should be?
• Questions like this aren't that difficult to answer. Nevertheless, you do have to think about the related calculations and how the "error" fits into the "big picture".
• Answer a question with more than "yes" or "no". You should explain (in complete sentences) "why" or "why not".
• The discussion should also answer these questions:
• In what ways did the things I did in this experiment allow me to achieve the object(s) as stated in the purpose?
• What did I learn from this laboratory experiment?
• How does this experiment apply to the lecture material?
In other words, you should explain what it is that your results tell you. Did you learn what you set out to learn?
• When you do an experiment as a group, you should compare notes. Theoretically, you should all come to the same conclusion. Everyone must write a conclusion -- in your own words!
• Think carefully about what each device you use measures. Grad cylinders and pipers measure volume; a pan balance and electronic balance measure mass. You calculate density (a derived unit) using mass and volume data. You want to be correct in your uses of terminology in your lab report.

• Do not obliterate or erase any data recorded in the notebook. If you wish to correct an error, draw a single line through the number or statement, then write the correct entry beside it.
• Be neat. Study the experiment and think it through in advance. Then select the clearest and most efficient way of recording your observations. This preparation will help you understand the experiment better and help organize your time. You will find that if you understand the experiment before you come to the lab and have your time organized, you will generally get out faster!
• Your ultimate goal is to maintain a complete record of your activities. If you do so, another student can probably repeat everything you did (correctly) without referencing anything other than your laboratory notebook!

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1. A winning team constantly strives to improve. The process of self-assessment is an effective way to build a winning team. Ultimately this leads to a better functioning group. In doing a group assessment it is very important to focus on the process - that is what the group experienced, felt and thought about while working on the group activity. You are not penalized for what you say; this exercise is intended to get you to think about how you could do a better job while in the laboratory.
2. Students often mentioned that they could afford to be "better prepared". A suggestion: in the experiments where it is obvious that different team members will be responsible for different chores, it would be in the best interest of the team to get together (for 20 ro 30 minutes) before lab and discuss how you might distribute the different responsibilities. Sometimes we will give directions in the lab manual; sometimes we will give "different" directions once you arrive in lab. All the same, getting together and agreeing on a plan is a good way to become more efficient!

• To assess participation and learning, use the following grid to rate yourself on your participation and learning in this exercise. Also give the (whole) group a rating. Use the scale: 0 = Poor, 1 = Fair, 2 = Good, 3 = Excellent

• To assess the process as a group, answer the questions:

1. What new information did we learn today?
2. What are three things we did well in functioning in a cooperative group?
3. What difficulties did we encounter that hindered the functioning of our group? How did we solve them?
4. What is one thing that our group could do next time so we can function better?

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Other Useful Links

• Keeping a Laboratory Notebook
• Important Lab Policies
• How to reach Dr. Bell-Loncella
• Links to interesting chemistry sites
• The Silberberg Web Page
• Center Point for General Chemistry
• Information about General Chemistry labs
• Schedule for Chem 1 Lab (C0113)
• Schedule for Chem 2 Lab (C0114)