Chem 321L is a one-credit laboratory course covering the procedures for classical volumetric, gravimetric, electrochemical, chromatographic and spectroscopic analyses. Students learn how to make accurate and precise measurements. Particular attention is given to data analysis and evaluation of data. Students are introduced to, and are expected to use, advanced data handling and error treatment methods.
The lab manual is available at the bookstore. (required)
Tu 9:35 - 12:25
MWF 10-11, 3-4 T 1-2, or by appointment
Byrd Center 315 304-876-5430 email@example.com
web page: http://WEBPAGES.SHEPHERD.EDU/DDILELLA/
CHEM 321 should be taken concurrently. Computer skills are not a prerequisite but students who do not know how to do basic computer spreadsheet operations should see the instructor as soon as possible to get special tutoring in these skills. With the aid of a computer spreadsheet program, the time required to do the lab reports will be significantly reduced.
Students are expected to attend all laboratory sessions. Students must get their lab notebooks signed during each period. Makeup labs will not be administered without a valid written excuse. Labs that are missed with a valid excuse may be made up at a time determined by the instructor. Students may NEVER work in a lab without permission of the instructor.
All data should be entered in a bound lab notebook. Before each lab the student should outline the work that will be done. The outline should include plans for preparing all solutions and a plan for the order in which the parts of the experiment will be performed. Notebook entries should be complete and neat. Your outline will be graded for each lab. Your notebook should be signed by the instructor in each lab period.
Reports are due one week after the completion of the experimental work. 2 points will be deducted from the score for every day that the report is late. The use of computer spreadsheets for data tabulation, analysis and creation of graphs is strongly recommended. A properly annotated printout of a spreadsheet is sufficient for the lab report.
Reports should include the following:
The first page should include your name, the title and number of the experiment, the name of your partner if applicable, and the dates on which the experiment was performed and submitted.
ALL data collected must be recorded in your notebook and must be included in the report.
All data should appear in tables.
All tables should include a title.
All columns in tables should include headings.
All table entries should have units unless the quantity is unit-less
Estimated uncertainties should be given for all measured quantities.
All plots should have titles.
The axes on plots should be labeled and the dimensions (units) of all quantities should be indicated.
All plots should be computer generated. Plots should be constructed so that they can be read to the maximum possible precision. Adjust the x and y ranges so that they are slightly larger than those needed to contain all of the data points.
A sample calculation showing every step used to treat the raw data should be presented. It is neither necessary nor desirable to show repeated examples of the same basic calculation. Describe the purpose of each step and indicate clearly the source of every quantity which you use in the calculation. Appropriate units should be used throughout the calculation. The sample calculations can be included on the spreadsheet printout. Be sure that purpose of each is clearly indicated.
For every measurement include an experimental uncertainty. The best time to determine the uncertainties is while you are doing the experiment. For example, if you measure a 10 mL volume that you believe to be accurate to 0.01 mL you record the measurement in your notebook as 10.00 ± 0.01 mL. Alternately, indicate in your notebook the type of volumetric glassware used so that you can look up the uncertainty later. Tolerances for volumetric glassware are tabulated in many textbooks and are usually posted in the lab.
For most of the experiments in this course multiple determinations will be made. The proper procedure in these cases is to calculate the standard deviation and 95 % confidence interval.
Deductions will be taken as follows
missing or improper units - 5 pts
missing data - 5 pts
missing sample calculations - 5 pts
The final grades are based on the lab reports and on the notebook. There are no tests or quizzes. Reports are graded on a scale from 0 to 100 and all have equal weight. The score on a report depends on the accuracy of your determination of the unknown and the clarity and completeness of the report. Typically the unknown is worth 20% of the grade but in a few cases, it is worth more. The instructor will give details as the experiments are done.
Grading for Course
The final grade will be based on the following scale
A 90 % to 100 %
B 80 % to 89+ %
C 70 % to 79+ %
D 60 % to 69+ %
The experiments have been designed with safety as a major consideration. However, the equipment and procedures will be unfamiliar to you and mistakes can and will happen. Be sure that you understand the hazards associated with the equipment and reagents before starting an experiment. Do not be afraid to ask questions. SAFETY GOGGLES OR GLASSES MUST BE WORN AT ALL TIMES. STUDENTS MAY NEVER WORK ALONE IN A LAB.