Laboratory Information Chemistry 141 Laboratory Information

Lab Books Get a lab book with prenumbered carbonless copy pages. Write your name on the front of the lab book. All data in the lab book must be written in blue or black ink. Do not tear any original pages out of the book, unless you are turning them in!!

Lab Books Be sure to write all data in your lab book in black or blue ink when you take the data. The only exception will be for data collected by the computer. Any data recorded on stray pieces of paper will be confiscated! No writeovers 375.788g No obliterations 639.824g No Erasing Cross out once and rewrite. 4.932g 5.382g 636

Lab Books Title Objective Procedure Safety Waste Treatment For the prelab: Complete the header Write a title, objective, procedure reference, safety, and waste treatment. Get is signed off before beginning your experiment. Everyone will do the entire lab on their own, but you may want to work with someone else to compare your results. Title e.g. Experiment 1 – Standard Deviation Lab Objective Procedure Safety Waste Treatment Exp. No. 1 Experiment Measuring Density with Different Types of Glassware Date 08/27/07 Name Jane Doe Lab Partner John Smith Locker No. 14B Course & Section No. Chem 141 & 5399 BeN FrON Instructor Signature Jane Doe Date 08/29/07 Witness/TA John Smith

Lab Books Write the objective of the experiment. Why are you doing this experiment? Objective: To determine the accuracy and precision of glassware and to calculate the standard deviation. To determine the density of…

Lab Books If you followed the procedure outlined in the handout provided in lab then reference the procedure, leave space for changes note any safety precautions note the waste treatment Procedure: Lehman, J. et al (2012). “Experiment 1: Measuring Density with Different Types of Glassware”, Grossmont College, Chemistry 141 Laboratory Manual (6th Edition, pp 1-12) El Cajon, California. Part B Procedure (You will make up your own, but sure to note it here). Safety: Wear safety glasses Waste Treatment: n/a

Lab Books Data and Observations: This should be a log of what you saw along with any tables of data that may be necessary. Another student should be able to pick up your lab notebook and repeat your experiment. Be sure to draw and label the equipment used. Table 1: Beaker Mass Measurements Trial Mass beaker + water Mass beaker after pouring water out Mass Water delivered by beaker 1 2 3 Uncertainty of beaker ± 1 mL Temperature of water 23.8 °C Density of water from CRC Handbook 82nd edition of 0.9973485 g/mL. Used Balance Number 1376 I filled the beaker to the 50 mL line with an eyedropper. It was very difficult to determine when the water level reached the line on the beaker. Etc…

Lab Books Copper sulfide precipitate was filtered and left in lab drawer to dry. The precipitate was a very fine black powder. BeN FrON Instructor Exp. No. 7 Experiment Copper Reactions Date 09/15/07 Name Jane Doe Lab Partner n/a Locker No. 14B Course & Section No. Chem 141 & 5399 At the end of the lab period, sign and date your lab book after your last data entry and get an instructor stamp. Exp. No. 1 Experiment Measuring Density with Different Types of Glassware Date 08/27/07 Name Jane Doe Lab Partner John Smith Locker No. 14B Course & Section No. Chem 141 & 5399 Signature Jane Doe Date 09/15/07 Witness/TA John Smith

Lab Reports Title Page Objective Introduction Procedure Results and Calculations Discussion Conclusion Questions Typewritten reports documenting your experimental results. Some reports will be abbreviated as noted in write-up instructions. Be sure to clearly label each section!

Lab Reports: Title Page Standard Deviation Experiment Fun with Glassware! Jane Doe Lab Partner: John Smith Chemistry 141 Section 5399 Instructor: BeN FrON August 29, 2007 completed September 7, 2007 turned in This will identify the experiment, you, the course, your class, your instructor, and the date(s) the experiment was performed. Very important so I can keep track of what you are handing in!

Lab Reports: Objective To determine the accuracy and precision of laboratory glassware and to learn how a standard deviation is calculated. To determine the density… Restate objective from lab book, but make sure to update it to make it more specific is something was left out.

Lab Reports: Introduction This section tells a little bit about the theory of the experiment and how it will be done. Be sure to give each equation and/or reaction it’s own line and label is eq. 1, eq. 2, rxn 1, rxn 2, etc…so that you can refer back to then by number later in your report. Introduction: When doing scientific experiments it is always necessary to minimize the error where possible. Unfortunately, however, it is impossible to completely avoid error. In experiments there are several types of error. They are random error, systematic error, and gross error. Random error is---

Lab Reports: Procedure Reference the procedure used and note any deviations from the published procedure. Procedure Followed procedure from handout: Lehman, J. et al (2012). “Experiment 1: Measuring Density with Different Types of Glassware”, Grossmont College, Chemistry 141 Laboratory Manual (6th Edition, pp 1-12) El Cajon, California. Part B: Density of Coke and Diet Coke Selected most accurate and precise piece of glassware the… … Note any changes e.g. In this experiment the liquid used for the density determinations was an isopropanol/water mixture.

Lab Reports: Results and Calculations A table summarizing major data like the one shown. For non numerical labs, summarize the data generated. Results and Calculations Table 1: Accuracy and Precision of Glassware Instrument Uncertainty Average volume Standard Deviation Precision (good, fair, poor) True Value %Error Accuracy (good, fair, poor) Beaker ±1 mL 50 mL Graduated Cylinder ± 0.1 mL 10.0 mL Pipet ± 0.02 mL 10.00 mL

Lab Reports: Results and Calculations The minor data is on the spreadsheet, which will also be turned in: Found at www.grossmont.edu/dianavance Show sample calculations for each type of calculation. (These may be hand written.) Results and Calculations Table 2: Beaker Mass Measurements and Calculations Trial Mass beaker + liquid (g) Mass beaker after dispensing liquid(g) Mass liquid(g) Average mass liquid deviation Standard deviation 1 xx.x xx. .xx 2 3 x.x Sample Calculation for mass liquid: xxx.xxg-xx.xxg=xx.xxg

Lab Reports: Discussion This is where you get to explain your results. Be sure to include quantitative numerical data where appropriate. e.g. average mass/volume, standard deviation, true value, percent error Be sure to include qualitative descriptions where appropriate. e.g. precipitate was a fine, white powder. Evaluate your data e.g. precision and accuracy Your sources of experimental error in your discussion must be supported by your running log in your data and observations section in your lab notebook. Discussion: The average mass of water held by the beaker was 43.2 g with a standard deviation of 0.1 g. This was less than expected based on the marking on the beaker which have an uncertainty of ± 1mL. The mass of water held was probably low because I filled my beaker to the bottom of the line and it may have been designed to fill to the top of the line. I also noticed that…

Lab Reports: Conclusion This is where you give the final result and evaluate your objective. This is essentially the punch line-- Conclusion The beaker held 53.4 grams of water with a standard deviation of 0.7 g with good precision and a percent error of 6.8%, so fair accuracy. The graduated cylinder…

Lab Reports: Questions Answer any questions posed in the lab here or on the sheet(s) provided in the lab manual.