Lab Skills Mastery Check

No Pre-lab Questions! No Results Questions! Just you playing around in lab! :)

NOTE: This exercise is a chance for you to demonstrate your ability to complete some fundamental lab skills that will be incredibly valuable to you in future science lab courses. You will be able to repeat these lab skills, under the supervision of your instructor, until both you and the instructor feel you have a mastery of the all of them. The lab skills that you will demonstrate mastery of are:

• Follow appropriate safety guidelines while in lab, such as wearing appropriate personal protective equipment (PPE) and following proper waste disposal and glassware cleaning protocols.

• Use a balance properly to precisely mass out a solid sample.

• Use volumetric glassware to precisely and accurately create a specific dilution of a solution

• Use Sheets/Excel to perform a linear regression analysis on data that obey a linear relationship.

Background

Throughout the semester, you have been performing several lab techniques that are critical to your success in future lab courses. For example, in our CHEM 205 labs, you will be preparing very precise solutions and dilutions using volumetric glassware. In our Biochemistry labs, one of the first labs you perform requires you to create a dilution. To ensure you have the confidence to perform those skills, we will work with you until you feel comfortable performing these skills.

Instructions

Your instructor will give you a time to show up to lab to perform the following lab skills. Please arrive on time (or early!), as many students will need to complete the lab skills in a short period of time (one 3.5-hour lab period) and your instructor will not be able to accommodate you if you are late. Please feel free to ask your instructor any questions throughout this lab, but ideally, try to come to lab well-prepared. Our overall goal is for you to leave this lab with a sense of mastery over these fundamental chemistry lab techniques. This is NOT a "lab practical/test!" Everyone who attends this lab will complete this exercise as long as you are willing to learn from your mistakes to improve your overall lab skills. That said, successful completion of this exercise is required to pass the course. Your instructor may give you a handout to complete as you go through each lab skill. Please turn it into your instructor upon completion of the lab skills.

Please make sure to begin and end each lab skill using the proper lab safety guidelines and glassware cleaning protocols that we have been using all semester in our lab.

Lab Skill #1: Weighing by difference
You will be given a small stock vial of solid sodium chloride. Please mass out, by difference, approximately 0.1 grams of the solid into the numbered white-capped vial supplied to you by your instructor. Please write your vial number and the exact mass to FOUR significant figures that ended up in your numbered vial on the handout supplied to you by your instructor. Please submit your full, numbered white-capped vial into your instructor. At that point, the instructor will determine if you have precisely and accurately added the amount stated on your paper.

Lab Skill #2: Creating a precise dilution of a solution
Your instructor will give you a dilution factor (e.g., 1/2) and final volume of the diluted solution (e.g., 10.00 mL) that they would like you to create as precisely and accurately as possible using the available glassware in our lab. On the handout, please note the glassware you want to use to create your assigned diluted solution and check with your instructor to make sure you are using the correct glassware. Once your instructor approves your glassware choices, please proceed to make your dilute solution with your instructor present.

Lab Skill #3: Using Sheets/Excel to create linear regression plot
On the handout supplied by your instructor, you will be given some lab data, similar to what we used in our previous labs, and be asked to create a linear regression plot. Your plot should display the appropriate plot and axis titles, as well as the equation of the line and the regression factor (R²). Please show/share your plot with your instructor.

Lab Skill #4: Safety
Your instructor will be taking note of whether you are wearing appropriate PPE while conducting all experiments and lab skills, and properly dispose of your waste and clean up your glassware once you are finished. :)

Before leaving lab, please check with your instructor to confirm that you have successfully completed all lab skills.