Chem 1411 & Chem 1412: Guidelines for Data Entry into Laboratory Notebooks. Title:

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1 Chem 1411 & Chem 1412: Guidelines for Data Entry into Laboratory Notebooks. Title: Objectives: What do you want to learn about the object of interest? Background: Part I: What do you already know about the System/Object of Interest? Part II: What do you NOT know about the System/Object of Interest? Answer in the form of How, Why, What, When, Where question format. (These notes are the primary curiosities of the study. Should be limited to objective interests.) Part III: (The Hypothesis) Pick one of the questions from Part II and suggest a method you would use to study the Object of interest. End entry with Why do you think your method will work and lead you to the answer that you seek? (Assume you have basic laboratory resources and instrumentation to conduct study. This is NOT a procedure section that comes next but is a logical statement as to how and why you think your approach will work based upon theoretical principles dealing with the subject. )

2 Experimental Methods: This section should begin with a list of chemicals and equipment to be used in the experiment. Follow with the step-by-step procedure you would use to conduct the study. The procedure should evolve from your theoretical hypothesis proposed method defined in the background. Part I: Chemicals, Equipment and Supplies needed for study: Equipment, Instruments and Supplies Needed Chemicals to be used in the Study* *MSDS documents are included in the Appendix II Part II: Experimental Procedure for conducting study: There are numerous ways to outline procedures. They should be sufficiently detailed about pre-lab preparation (cleaning and calibration of equipment), set-up and/or construction of apparatus (Diagrams and figures should be included if needed to assist reader in set-up of equipment. This is usually included in an appendix at the end of the write-up. Example: [Step (#): See figures A E Appendix I] Also, it should be understood that this section well be very flexible in the experimental process. As you (the experimentalist) progress through the study, the procedure will most likely be modified several times in order to obtain reliable results. Once a reliable procedure has been developed, then this will be the best experimental process for the study. In the process of scientific discovery, the initial procedures outlined rarely are acceptable and require modification to achieve reliable data trends. Step

3 Data and Data Tables: Data is generated in two forms, Raw (or, natural) Data and Derived Data. Raw Data is what is generated by the natural character of the object of interest. Such are results of direct observer interaction using ones 5 senses or for more accuracy, instrumental analysis. Typically, one of the variables is a Independent Variable ; i.e., something the experimentalist varies, and another a Dependent Variable ; i.e., the outcome of the experimental variation. Examples: Measured Radioactive Decay as a function of time Rate of candle burn as a function of time Weight as a function of Volume Bulb Brightness as a function of Applied Current Derived Data is the result of applying the Raw Data to an equation that defines a physical or chemical property of the object of interest. Density is Mass per unit Volume ( D = M/V). The Raw Data is the Mass values and Volume values measured, and the calculated density is the Derived Data. Derived Data also correlates trends in raw data expressed in graph form. Typically, experimental trends are represented in the form of a two dimensional Cartesian Graph with the Independent Variable. on the x-axis and the Dependent Variable on the y-axis. Most experimentalists combine the Raw Data and the Derived Data in one table that is filled in as the experimental results are generated. The Derived Data results are easily computed in sequence as the data is entered. Table 1: Determination of %Water in a Hydrate Salt Data Trial # Exp 1 Exp 2 Exp 3 Exp 4 Exp 5 A = Crucible (Empty) gms B = Crucible + Hydrate (Before Heating) gms C = Crucible + Hydrate (After Heating) gms Target* C C C C D = Wt H 2O removed = C Before Heating C After Heating = (B C) E = Wt Hydrate Salt = [(Crucible + Hydrate) (Crucible Empty)] gms = (B A) %H 2O in Hydrate = [Wt H 2O removed/ Wt Hydrate Salt] x 100% = (D/E) x 100% *Target Wt After Heating = [(B) 0.36(B) (A)] % 35.93% 34.95% 37.01% 35.88%

4 Table 2: Statistical Analysis of %Water in a Hydrate Salt Exp # %Water in Hydrate Salt Average %HOH 35.95% Standard Deviation 0.73% Confidence Interval* CI = 2(STDEV) = 1.46% Range of Reliability Avg ±CI = ± 1.46% CI = 2(STDEV) for n-trials 10 CI = STDEV for n-trials > 10 Graphic Trends: Graphs are figures that illustrate (typically in two dimensions) the variation of a dependent variable as a function of an independent variable. The graph figures should contain the following: Figure number Title of the relationship trend A molecular-form reaction if applicable Labeling of x and y axis Annotations of important elements in the trend Eample: ph vs Volume of Base in a typical Acid/Base Titration:

5 Conclusions: A conclusion is a pragmatic statement of objective outcomes. Experimental objectives were defined at the beginning of the project and outcomes are defined in the conclusions. Typically, an average of multiple trials with an error analysis is emphasized. This is in the form of Average ± Confidence interval if the number of trials is 10 or, Average ± Standard Deviation is the number of trials > 10. The Confidence Interval and Standard Deviation values are statistical probabilities that if one follows the procedures defined in this study, there is a defined probability of reproducing the results and outcomes of the study. If Confidence Interval is used for 10 or less trials, there is ~ 90% probability of reproducing the outcomes, and if the number of trials is greater than 10 trials then the Standard Deviation is approximately equal to the Confidence Interval and the reproducibility is ~70% or greater. Example: Conclusion of a study for determination of the density of CO 2 gas: The density of CO 2 gas at 25 o C and 755 mmhg was found to be 1.72 ± 0.15 gms/liter giving a Range of Reliability of 1.57 gms/l to 1.87 gms/l. This represents a %Error of 3.4% below the accepted value of 1.78 gms/l at the same conditions of temperature and pressure. Discussion: The Discussion is a review of factors and issues that directly affect the outcomes of the experiment. Typically, they are limited to the variables used in calculated results based upon the definition of a physical or chemical property of matter. Example, density is mass per unit volume ( D = M/V). The discussion should be limited to reviewing the issues (if any) related to collection of mass values and volume values used to calculate the density values. The statements made in this are direct without excess embellishments and should be made in the impersonal tense of the dialog. Example: The determination of mass values using the Veritas M Series Analytical Balance were found to be accurate to 4 decimal places ± gram. If several analytical balances are accessible for the experiment, it is recommended that data be collected using only one of the available instruments. Such will significantly increase reproducibility through the data collection process. Volume values were collected by displacement of water in an inverted graduated cylinder as the CO 2 gas is generated. The cylinder volume measurements were accurate only to ±0.10 ml limiting the experimental outcomes to the same degree of error. Caution is also suggested when changing apparatus that no external contamination of the equipment occurs. Due to the 4-digit accuracy of the analytical balance, the error in this instance can be significant if caution is not observed.